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HOW NEW FTC HI-FI RULES AFFECT YOU
WORDS LARGEST SELLING LIECTRONICS MAGAZINE
NOVEMBER 1974/604
What's New in 1975 Color TV Receivers
I
s_a
Muitimeter Range Extender
artier Opportunities for Tech Reps
Direct-Conversion AM/SSB Project
Reps
Pioneer SX-636 Stereo Receiver
Pickering OA-3 Stereo Headphores
American Circuits & Systems MK1Function Generator
Royce 1-600 CB Mobile Transceiver
Drake SPR-4 Communications Receiver
ZOZ
4
tsi;Nrr
1
ya
V10t13
3,01
S
3dC h
;:',0
El
T60401600 SSS 11024.173
"
9lptllltlIIIP1
speed while a record is playing. Both of
these sophisticated units are even
equipped with a
strobe light directed
at the strobe marks
for easy viewing.
Pioneer's engineers
really think of
everything.
Electronic speed adjustment for each speed
Automatic features without
automatic drawbacks
ble that's right for you.
PL-A45D
PL-51A
PL -71
Belt
4 -pole synch.
Direct
DC Servo
Direct
DC Servo
±2%
±2%
lore than 47dB More than 55dB More than 60dB
0.05% (WRMS)
Static Bal. "S-
8'1/16"
0.06% (WRMS)
Static Bal. "S"
81i/if"
12"
121/4"
121/4,
static Bal.
2
"S"
lbs. 3 oz.
$169.95
3
lbs. oz.
$249.95
1
mu,
lin'r,ages to p-ovide the necessary tun'_.:
cycling moticn, tee PL -A45D uses a
separate, precision gear motor just to 7,101:e
the tonearm n accordance with your
instructions. Its other 4 -pole synchrorDus
motor is free
only the
12 -inch aluminum
alloy die -cast platter
without interruption
or change of torque
and speed.
If you prefer to let your tonearm and
turntable do all the work, consider Pioneer's
all new PL -A45D. With it you can play your
records without ever touching the tonearm.
Unlike other single play automatics which
depend upon complicated mechanical
).1% (WRMS)
II
83/41P
3 lbs- 8 oz.
5299.95
Automatic ope-ationmanual orecisi *)n
Superb S- Shaped tonearms
for better tracking
Ths tonearm of every
Pioneer turntable system
the 'Sst pee"
design, for aptirnurn
groove tracking. Al are
s3atically balarced and
all use adjustable counter u'eights Nita direct read cut of tracking force. All
t ave adjus-. able
anti- s'sate control and
cil- damped cuing for
t7near:n
t're gentlest application
(Of ideal racking
c'f sty`us tip to record
groove. t u nt'' elp at }slug in e;artr dco shells
'insure positive siect!icai contact nn,d
optimum stylus position and angle for io,ve;'
disstorticn f-nd red'aced record varan_
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The tradition of unexcelled
performance
Still, all of these features and refinements alone do not guarantee the per`ormance specifications of Pioneer's new
turntables. Each tonearm and turntable
platter combination is shock mounted in
its specially designed natural grain cabinet
(with hinged dust cover). Precision machining of all rotational parts of each unit, plus
a program of continuous quality control
insure that each Pioneer turntable wi l meet
or exceed its published specifications -a time honored tradition with all Pioneer
components.
Manual turntables- choice o'
the professionals
Engineers, experts and enthusiasts
,rgree: to get the best performance, you
need a manual turntable. And to get the best
manual turntable, you need a Pioneer.
Every Pioneer manual turntable offers a
level of precision and performance unparalleled in its price range. And every
one is a total system
complete wit) dust
cover and base -- and designed 'or
years -of professional trouble -free scund
-
reproduction.
For the
best manual turntable
get a Pioneer.
The manual turntable is rapidly
becoming the first choice of hi -fi enthusiasts
everywhe-e. The reason why is quite simple.
Todaa's enthusiasts are more knowledge able, more sophisticated and rrore involved
with their music. And only the manual
turntable can provide the involvement
End performance they demand
Al Pioneer, this trend comes as no
surprse. We have long recognized the
superiority of the manual turntable. And
long recognized a simple fact: a record
changer in no way improves pe-formance.
I, can detract from it.
As a result, we now offer the finest and
most complete lme of manual turntables
availaole. Manua turntables that are
designed with the needs of today's hi -fi
enthusiast bn mind. Turntables that are
engineered for precision resporse.
When yOL get right down to it. good
cord playing equipment really has only
two requirements: uniform rotation of a
turntable, and accurate tracing of a record
groove by a tonearm and its cartridge.
P'cneer s engineers have long recognized that these requirements are best met
by single -play turntables and precision
engineered tenearms. Our five new belt drive and direct -drive turntable systems
mean you needn't settle for the higher wow
r
and flutter and the poorer signal -to -noise
ratios (rumble) of record changers. Whether
you've budgeted $1C0 or $300 for this vital
element of your high fidelity system. there's
a Pioneer turnable tnat outperforms any
record changer in its price class.
Consider the performance advantages
Belt -drive, featjred in Pioneer's PL -10.
PL -12D and PL -A45D, means smoother,
more uniform platter rotation than can be
achieved witt typica idler -wheel /pulley
arrangemems normally found in record
changers. Even chargers equipped with
synchronous mo "ors transmit
vibration to the turntable platter. This is
picked up as low-frequency rumble by the
tonearm and cartridge. By driving the platter
with a precision- finished belt, vibration
is effectively absorbed before it can be
translated to aud'ble rumble.
^..
j
''
fr
ße!t-drive
rumble -free
r.
tetic
i
,
.i,
. '._
/
L'irect -drive motor
reduces friction
Pioneer's direct -drive models, PL -51A
and PL -71 go even a step further in achieving noise -free. precision planter rotation.
The DC electronically controlled servomotors used in these models rotate at
exactly the required 331/3 or 45 rpm platter
speed. Their shafts are directly connected
to the center of the turntable, with no intermediate pulleys or other speed reduction
devices. This means no extra frictionproducing bearing surfaces.
Because of the unique technology
embodied in these new, direE.t -drive motors,
it's possible to control their speed electronically. This is more precise tl an any
mechanical drive system. Both our PL -51A
and PL -71 offer irdividua.l pitch control for
both 331/3 and 45 rpm speeds. Their turntable platters are edge -fitted with st -oboscopic marks, so you can adjust precise
Choose tIe Pioneer turntz
Pt --12D
PL -10
Model
Belt
Belt
Drive system
4 -pole synch.
4 -pole synch.
Drive motor
Speed control
More than 47dB More than 47dB
S/ N (Rumble)
0.1% (WRMS)
Wow & Flutter
0.1% (WRMS)
Tonearm Type
Static Bal. "S" Static Bal. "S"
811/,6"
8%v"
Tonearm Length
Turntable
12"
Diameter
12"
Turntable
2 lbs. 3 oz.
Weight
2 lbs. 3 oz.
Price:
$1'9.95
$99.95
-
-
ti
r
For the
best performance,
get a manual
turntable.
when you want something t ettE r
U.S. Pioneer Electronics Corp., 75 Oxford Drive, Moonachie, New Jersey C7074
1500 G-eenleaf, Elk Grove Village, Ill. 60007 /Canada S.H. ParkEr Co.
/Midwest:
Los
)0248
Angeles
West: 13300 S. Estrella,
CIRCLE NO. 41 ON READERS SERVICE CARD
Pickering cartridges feature low frequency
tracking and high frequency tracing ability*
Pickering offers you The Best of Both
Worlds" in discrete 4- channel and in
stereo cartridges. These cartridges have
been specifical y designed and engineered
to peak specification and performance
characteristics. They possess traceAbility,
vital for both stereo and discrete playback.
For example, take the case of discrete
(B)
(C)
playback. Ycu are looking at a model of a
discrete groove, magnified 3,000 times
(figure A). You can see it is made up of
complex groove undulations. This makes
the demands on the cartridge and its
stylus much greater than ever before. The
left side of the groove possesses all of the
information recorded on the left side of the
room, and the right side likewise. The
stereo signals for the front speakers are
represented by the broad sweeps (figure
B), and the special discrete high frequency tone carrier is represented by the
wiggles on the same groove walls (figure
C). This high frequency carrier centered
at 30,000 Hz, demands a superior stylus
assembly (and shape of the tip) which we
call our QuadrahedralTM another Pickering
exclusive wh ch makes it possible for the
stylus to trace both the stereo and discrete signals in the groove.
So, the QuadrahedralTM stylus picks up
(A)
all 4 signals, which the computerized demodulator sorts for the amplifier, which in
turn transmits the sound to the proper
speaker.
So, whether you look forward to the
fabulous reality of discrete 4- channel
sound in your home, or the finest stereo
to satisfy your listening taste
depend on
the traceAbility of Pickering cartridges to
make possible "The Best of Both Worlds ".
the world of stereo and matrix, and
the world of discrete 4- channel.
-
.
.
.
For further information write to
Pickering & Co., Inc., Dept. PE
Sunnyside Blvd., Plainview, New York 11803
PICKERING
'for those who can hear the difference"
TM- PICKERING TRADEMARK
CIRCLE NO. 30 ON READERS SERVICE CARD
2
POPULAR ELECTRONICS
NOVEMBER 1974 VOLUME 6, NUMBER
5
Popular Electronics
WORLD'S LARGEST- SELLING ELECTRONICS MAGAZINE
FEATURE ARTICLES
HOW THE NEW FTC HI -FI RULES AFFECT YOU!
The buyer must still be wary of power claims.
WHAT'S NEW IN COLOR TV RECEIVERS FOR 1975
Leonard Feldman
39
Art Margolis
41
46
NEW DOLBY -ENCODED FM BROADCASTS
How new FCC rules affect FM reception
Forrest M. Mims
BASIC DIGITAL LOGIC COURSE
Part 2: Concepts and circuits
CAREER OPPORTUNITIES FOR THE TECH REP
COMPUTER TERMINALS ARE COMING
Edward Roberts
57
Allan C. Stover
Leslie Solomon
69
Roger Legge
79
John
Frye
88
Joseph O'Donnell
32
Jim White
48
Hollabaugh
52
& H.
78
Time savers for the home and small business
ENGLISH LANGUAGE SHORTWAVE BROADCASTS
November to February
THE SIMPLEST TEST GEAR
T.
Test probes can solve many service problems
CONSTRUCTION STORIES
Giancarlo Punis
BUILD A LASER TV SYSTEM
Transmit and receive B/W pictures on
a
&
laser beam
BUILD A DIRECT -CONVERSION COMMUNICATION RECEIVER
Good performance at
a
fraction of the cost of
a
superhet
MEASURE LOW MILLIVOLTS WITH A MULTIMETER
John
F.
Range expander increases sensitivity by X10 or X100
Thomas R. Fox 54
BUILD A VERSATILE DIGITAL LED THERMOMETER
COLUMNS
HOBBY SCENE
STEREO SCENE
Editorial Stall
17
Ralph Hodges
22
Glenn Hauser
80
Len Buckwalter
86
Lou Garner
90
Blazing speakers
DX LISTENING
"Secret" shortwave stations
CB SCENE
CB to the rescue
SOLID STATE
Circuits using field -effect transistors
PRODUCT TEST REPORTS
59
60
PIONEER MODEL SX -636 AM /STEREO FM RECEIVER
ROYCE MODEL 1 -600 MOBILE CB TRANSCEIVER
PICKERING MODEL OA-3 STEREO HEADPHONES
DRAKE MODEL SPR-4 COMMUNICATIONS RECEIVER
AMERICAN CIRCUITS & SYSTEMS MODEL MK1 FUNCTION GENERATOR
61
66
68
DEPARTMENTS
Art Salsberg
EDITORIAL
4
Run lt Up The Flagpole
LETTERS
NEW PRODUCTS
NEW LITERATURE
NEWS HIGHLIGHTS
POPULAR ELECTRONICS. November 1974, Volume 6. Number 5 Published monthly at One Park Avenue. New York. NY 10016. One year subscription rate for U S.. Possessions and Canada, $6.98. all other countries.
$8 98. Second class Postage paid at New York. NY and at additional
mailing offices. Authorized as second class mail by the Post Office Department, Ottawa, Canada and for payment of postage in cash. Subscription service and Forms 3579. P.O. Box 2774. Boulder. CO 80302.
POPULAR ELECTRONICS Including ELECTRONICS WORLD. Trade
Mark Registered. Indexed in the Reader's Guide to Periodical Literature.
COPYRIGHT c. 1974 BY ZIFF-DAVIS PUBLISHING COMPANY. ALL
RIGHTS RESERVED.
NOVEMBER 1974
6
12
16
27
Ziff -Davis also publishes Boating. Car and Driver. Cycle. Flying. Modem Bride. Popular Photography. Skiing and Stereo Review.
Forms 3579 and all subscription correspondence should be addressed
to POPULAR ELECTRONICS. Circulation Dept.. P. O. Box 2774, Boulder,
CO 80302. Please allow at least eight weeks for change of address. Include your old address. as well as new-enclosing. if possible. an address label from a recent issue.
Editorial contributions must be accompanied by return postage and
will be handled with reasonable care: however publisher assumes no
responsibility for return or safety of art work, photographs. models. or
manuscripts.
3
Popular Electronics
EDGAR W. HOPPER
Publisher
ARTHUR P. SALSBERG
Editorial Director
LESLIE SOLOMON
Technical Editor
Editorial
JOHN R. RIGGS
Managing Editor
EDWARD I. BUXBAUM
Art Director
ALEXANDER W. BURAWA
Associate Editor
JOHN McVEIGH
Assistant Editor
ANDRE DUZANT
Technical Illustrator
ELLEN S. FINKELSTEIN
Editorial Assistant
LEN BUCKWALTER
LOU GARNER
JULIAN D. HIRSCH
RALPH HODGES
WALTER G. JUNG
MILTON S. SNITZER
Contributing Editors
JOSEPH E. HALLORAN
Advertising Director
JOHN J. CORTON
Advertising Sales
LINDA BLUM
Advertising Service Manager
PEGI McENEANEY
Executive Assistant
STANLEY NEUFELD
Associate Publisher
FURMAN H. HEBB
Group VP, Electronics d& Photo
ZIFF -DAVIS PUBLISHING COMPANY
Popular Electronics
Editorial and Executive Offices
One Park Avenue New York, New York 10016
212 -725 -3500
William Ziff, President
W. Bradford Briggs, Executive Vice President
Hershel B. Sarbin, Senior Vice President,
Secretary, and Treasurer
Philip Sine, Senior Vice President
Phillip T. Heffernan, Vice President, Marketing
Frank Pomerantz, Vice President, Creative Services
Arthur W. Butzow, Vice President, Production
Edward D. Muhlfeld, Vice President, Aviation
and Automotive Divisions
George Morrissey, Vice President
Sydney H. Rogers, Vice President
Sidney Holtz, Vice President
Lawrence Sporn, Vice President, Circulation
Edgar W. Hopper. Vice President. Electronics Div.
Midwestern Office
The Pettis Group, 4761 West Touhy Ave.,
Lincolnwood, Illinois 60644, 312 679 -1100
GERALD E. WOLFE, GEORGE B. MANNION
Western Office
9025 Wilshire Boulevard, Beverly Hills, CA 90211
213 273 -8050; BRadshaw 2 -1161
Western Advertising Manager, BUD DEAN
Japan: James Yagi
Oji Palace Aoyama; 6-25, Minami Aoyama
Chome, Minato -Ku, Tokyo 407 -193016821,
582 -2851
6
RUN IT UP THE FLAGPOLE
As some readers know, a Notice of Proposed Rule Making by the FCC
is simply the Commission's public pronouncement that it is considering
a change in Rules and Regulations. Of course, some proposals never
come to fruition, while others are severely modified before adoption,
depending on comments received by interested persons and groups.
For example, the FCC created a furor almost two years ago when it
invited comments on its proposal to transfer the 220 -MHz amateur radio
band to CB to relieve congestion. We haven't heard a word since, and
suspect that hamdom's vociferous outcry against it has shelved it for a
while. Now there are some startling, new proposals concerning CB, plus
some action. To keep you abreast of what's going on, here are some
current developments.
In the action area, CB'ers can now use omnidirectional antennas and
support structures that are 60 feet above ground! (Present 20 -foot restrictions on directional antennas remain.)
On the proposal side, the FCC proposes to allocate the 27.230 -MHz to
27.540 -MHz band to the Class D Citizens Radio Service as a means of
relieving congestion. This would add 47 channels to the existing 23
channels if eventually adopted. Further, the Commission is toying with
the idea of allowing hobby -type activities to be communicated via CB so
long as it doesn't relate to use of the radiotelephone equipment
considering deletion or modification of rules on relaying messages by
licensees ... reducing the age requirement from 18 years to 16 years
using Channel 11 (27.085 MHz) as a calling channel to establish contact
for communicating on another channel ... reducing the communications silent period from five minutes to one minute (that's five on and one
off) ... and modifying the requirement of a transmitting station to use
both its call sign and that of the station being contacted to the sender's
call sign only, among other proposals issued.
In another recent proposal, the FCC admits its failure to eliminate
extensive use of r -f power amplifiers (those illegal "linears ") by Class D
stations. As a consequence, the Commission wishes to prohibit sale or
lease of linears in the 20- to 40 -MHz band, excepting multiband equipment for use in the Amateur Radio Service and single -band amplifiers
made on a single-unit basis. Until further clarification, presume that the
latter allows one to build his own linear. Under any circumstance, of
course, linears cannot be used legally for Class D communications.
It's clear from the proposed major rule amendments that the Commission intends to enhance two -way short -range radio communications for
individual citizens. Offhand, we like some of the proposals and have
reservations on others. Nonetheless, we're pleased to learn of some
positive FCC action concerning CB. Ignored, however, was a way to
compel CB'ers to obtain a license and to use call signs.
Running such proposals up the flagpole provides the FCC with input
from a variety of public sources. Therefore, proposals generally take
considerable time to finalize, if acted upon at all. And should additional
channels actually be added at some future time, you can be sure that
manufacturers will be delighted to sell you an add -on adapter to expand
your radio service. So go ahead and buy that CB rig, if that's what you're
planning to do. It's the same suggestion offered here when Class E, now
apparently dormant, was proposed. And it proved to be a sound one.
.
.
.
.
I
F'DAVif
?
ShiqG
Member Audit Bureau
of Circulations
The publisher has no knowledge of any proprietary
rights which will be violated by the making or using of any
items disclosed in this issue.
4
NOVEMBER 1974
Earn
an extra
$2000
per year
Find out how you can earn an
extra $2000 or more per year restoring only a few color and black
and white tubes per week. Full
color brochure shows you how
to make more money and satisfy more customers on almost every call. Write to-
day!
New
467 CRT
Restorer /Analyzer
$279*
With the profit restorer!
Profit in the home. After replacing a component
you've often noticed a less than perfect picture. It's
almost always due to a weak picture tube. The few
minutes you spend with the 467 Restorer will give
your customer brilliance and sharpness that will make
her pleased to pay for the improved picture.
TriDynamic true test. The B & K TriDynamic method
tests all three guns simultaneously. It measures true
beam current that passes through G1 aperture, unlike
other testers that measure meaningless cathode to GI
current. Leakage indication even includes cathode to- cathode and there's an exclusive B & K focus continuity test.
Profit in the shop. "Sixty -five dollars and the picture
still doesn't look as good as it used to!" How many
times have your customers said that to you? You need
not hear it again! Use the 467 Restorer on every major
job and your customer will thank you for returning his
set working like new.
Simplest operation. Exclusive integrated circuitry
lets you test all picture tubes with the same, defined on- the -front -panel procedure ... including "in- line
Trinitron and tubes with common G1 and G2. See your
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distributor or write Dynascan.
optional sockets also shown.
Most -Powerful Rejuvenation, but most gentle too.
There's only one CRT Restorer that restores the picture to like new and analyzes tube condition so accurately that you can safely guarantee restoration for
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PRODUCTS Of
DYIVASCAIZI
1801 W. Belle Plaine Ave.
Chicago, IL 60613
stripping.
CIRCLE NO.
NOVEMBER 1974
6 ON
READERS SERVICE CARD
(312) 327 -7270
5
í=
Letters
S
IT TAKES TECHNICAL KNOW -HOW
What gives Johnson CB two -way
radios their "extra sock" for longer range? Built-in
Electronic Speech Compression, that's what! It's the
kind of engineering you expect from U.S. -made
Johnson radios
backed by a full 1 -year parts and
labor warranty with over 700 service centers nationwidle.
...
The implication in "How to Set Up a Home TV Service Shop"
(August 1974) that anyone with a small amount of electronics
knowledge and an investment in the neighborhood of $50 can
start his own business in color TV servicing is ridiculous. Although am not aware of author Margolis' competence or history
in color TV servicing, challenge his statement that only a small
percentage of TV troubles require great skill and expensive test
equipment. On the contrary, it has been my experience and the
experience of my associates with whom have discussed this
article that a correct statement of fact would be that only a small
percentage of TV troubles are simple and easy to repair.
EWELL A. FERGUSON, JR., CET, Executive Director
North Carolina Electronic Technicians Assoc. Inc.
I
I
I
PRICES START AT UNDER $100!
SEND COUPON FOR FREE CATALOG!
F. F. Johnson Co
Dept. PE
Waseca, Minn. 56093
Name
Address
City
State
Zip-
In Canada: A. C. Simmonds & Sons. Ltd.
CIRCLE NO. 33 ON READERS SERVICE CARD
YTIIING
YOa:`::'::{}.
WANTED TO KN
ABOUT CD IGNITION_.>
SYSTEMS BUT DIDN'T::
KNOW WI-IOM TO ASK.
Send for FREE Tiger booklet (20
pages) which answers all your
questions.
Name
Address
City
State
Zip
CLIP OUT THIS AD AND SEND
TO-
TRI-STAR CORP.
0. Box 1727 Dept.
Grand Junction, Colo.
P.
E
81501
CIRCLE NO. 39 ON READERS SERVICE CARD
6
The article did not focus on color TV servicing only nor even
solid -state receivers only. We know service technicians who have
started with as little as $50, though they continually added to their
parts inventory and test equipment. The article was directed to
readers who have a good technical knowledge of TV receiver
circuits, are presently employed in another area of electronics,
and who yearn for their own business. (We apologize if our reader
target was not clear.) For these skilled people, most TV troubles
are easy to isolate and correct. For untrained persons, this is, of
course, untrue.
LEGALITY OF CB "PHONE PATCHES"
The Commission's (FCC) Rules contain no prohibition against
the manual interconnection of a Citizens Class D radio station to
commercial telephone facilities under conditions whereby a
properly authorized operator is available to monitor and control
the operation of the Citizens Radio station. Particular attention
should be given to the provisions of Paragraph (d) of Section
95.119 which prohibits remote control of a Class D station and
Section 95.87 (a) which requires a licensee to maintain control at
all times over the transmitters operated under his license. "Phone
patch" devices which permit telephone calls to automatically
actuate a Class D station are in violation of both stated sections.
Messages from a commercial telephone can be fed directly into a
Citizens Class D transmitter through a phone patch only if an
authorized operator had direct manual control of the transmitter.
Attention should also be given to Section 95.83(a)(14) of the
FCC Rules which states in essence that a Citizens radio station
shall not be used foi relaying messages or transmitting communications for a person other than the licensee or members of
his immediate family.
The connection of a phone patch to the telephone lines for
interstate and intrastate communication is governed by tariff
regulations filed by the telephone companies with the FCC and
the state regulatory agencies. Generally, these regulations permit
the connection of customer -provided communications systems.
Connection by acoustic /inductive means is subject to the condition that certain "minimum protection criteria" regarding signal
input power are met. Local telephone companies will explain
these criteria to interested licensees and operators. On the other
hand, direct electrical connection can be made only through a
connecting arrangement provided by the telephone company.
CHARLES A. HIGGINBOTHAM
Chief, Safety & Special Radio Services Bureau,
Federal Communications Commission, Washington, D.C.
POPULAR ELECTRONICS
Ampzilla
FEEDBACK ON DOUBLE -SIDED PC BOARDS
The process detailed in "How To Make
Double-Sided PC Boards" (June 1974) can
be simplified in the following manner:
First, photo- reverse the exposure masks.
Use IC-pad holes as references to align the
reversed films, and tape the edges together
along three sides. Punch holes through
both films in unused areas (preferably in
each corner) of the layout.
In a safe -lighted area, slide the pc blank
between the films and apply small squares
of transparent tape over the punched holes
to secure the film to both sides of the blank.
Expose the board, one side at a time, using
a photographic contact printer with foam
backing. Finally, remove the tape and develop and etch the blank.
is here...
Why spend $750 to $1200 dollars for
an
amplifier? The Great
American Sound Company
with a full comple.nentary series connected out .ì put for much less. In short
¡AMPZILLA is here. In the
September 1974 Popular Elecronics, Hirsch -Houck Labs
lys '... solidly in the audio
nonster amplifier class
THD was less
using 8 ohm loads
up
than 0.01% for all power levels
all in
.. '(per channel)'
to 200 watts
all we cannot imagine a less expensive way of obtaining several hundred watts.' Yes, we, your friendly GAS company, have the goods
complete with a fan for ultra cool operation. Available with direct reading power meters in kit ($375) or fully assembled ($5251. Also the
same amp but no meters in kit ($340) and assembled ($475). Write us
for complete specs, or read Popular Electronics, September 1974.
sells one
GERALD G. GRAMM
.
Quantico, Va.
.
feel must criticize Mr. Burawa's statement that "If you can trace a circuit, you
can design any type of pc board." am
afraid that many readers are going to get
themselves into difficulties if they follow
this advice. Pc boards are not a toy for the
unskilled. Having been in the pc -board design field since its inception, can attest
that it takes many hours of training to acquire the design knowledge required for
making pc boards.
Also lacking in the article was any mention of the fact that pads or land areas are
chosen in relation to the hole size for the
component lead or that there are strict
rules on clearances between components
and the foil conductors. The greater the
packaging density, the more problems will
be encountered and the more you must rely
upon the rules that govern pc designs.
Hence, without a formal education in design, expensive trial and error are going to
cause short tempers.
I
.
I
I
Crown Point, N.Y.
"I do not deny that formal training would
better prepare the experimenter for tackling pc board design and fabrication. But I
also feel that it is not absolutely necessary
in the great majority of cases. I contend
that if you can trace a circuit, you can design just about any type of pc board. I
would only add that good layout procedures be practiced in high -gain, r -f, and
other critical designs to avoid crosstalk,
-Author
feedback, etc.
LINEARS ON CB ARE
A
NO -NO
would very much appreciate any information you can pass on with regard to
using a linear amplifier with my CB transceiver.
Name Withheld
I
.
.
...
...
.
Available directly from
I
RICHARD MAYER
.
THE GREAT AMERICAN SOUND COMPANY, INC.
8780 Shoreham Drive, West Hollywood, California 90069
CIRCLE NO. 18 ON READERS SERVICE CARD
The New
Electronics
Book
Sophisticated Electronics For Fun
By Joe R. Urschel
A totally new step by step guide to the "how to" of
modern electronics, with 190 illustrations in this big
8 1/2" X 11" book.
Sophisticated
Electronics
For Fun
Ouick
s
C°°11
Plus
What is
tat Iwo
New
Free
Now, whether you're a novice or an expert you can benefit from this fact filled,
easy to read book. Plus how to use TTL logic, in a non -academic approach to
analog and digital electronics.
Special Bonus
two electronic slot machines
Complete tried and proved plans to build
electronic clock with chimes juke box with no moving parts computer game.
Available in the Chicago area at Kroch's & Brentano's bookstores.
Order Today
r
9
29 S. Wabash Ave., Chicago, IL 60603
copies of Sophisticated Electronics For Fun, $6.95 each. If not
may return the book(s) within ten days for credit or refund.
KROCH'S & BRENTANO'S
Please send me
completely satisfied,
I
PE
Name
Address
City/State /Zip
The best information we can pass on is
don't. The use of a linear power amplifier
with a CB transceiver is forbidden by the
FCC rules.
NOVEMBER 1974
enclosed
Payment in amount of $
Charge my K & B account
Expiration date
Charge my Master Charge or Bank Americard
Illinois residents add 5% tax. Free delivery in Chicago and suburbs. Elsewhere add 400 per book mailing &
handling charge. Sorry. no C.O.D.'s.
CIRCLE NO. 23 ON READERS SERVICE CARD
J
7
Whete do
the pms geit their
training?
Almost half of the successful TV servicemen have
home study training and among them, it's NRI 2 to
It's a fact! Among men actually making their living repairing
TV and audio equipment, more have taken training from NRI
than any other home study school. More than twice as many!
1 e
8
POPULAR ELECTRONICS
Not only that, but a national
survey* performed by an
independent research
organization, showed that the
pros named NRI most often as
a recommended school and as
the first choice by far among
those who had taken home
study courses from any school.
Why? Perhaps NRI's 60-year
record with over a million
students...the solid training
and value built into every NRI
course... and the designed-forlearning equipment originated
by NRI provide the answer.
But send for your free NRI
catalog and decide for yourself.
Two Famous Educators...
NRI and McGraw -Hill.
NRI is a part of McGraw -Hill,
world's largest publishers of
educational material.
Together, they give you the
kind of training that's geared
for success...practical know how aimed at giving you a real
shot at a better job or a
business of your own. You
learn at home at your
convenience, with "bite- size"
lessons that ease learning and
speed comprehension. Kits
designed to give you practical
bench experience also become
first -class professional
instruments you'll use in your
work.
*Summary of survey results upon request.
NOVEMBER 1974
25" Diagonal Color TV...
Professional Instruments
As a part of NRI's Master
Course in TV /Audio servicing,
you build a big-screen solid
state color TV with every
modern feature for
great reception and
performance. As you
build it, you perform
stage-by -stage
experiments designed
to give you actual
bench experience
while demonstrating
the interaction of
various stages of the
circuitry. And your
TV comes complete
with console cabinet,
an optional extra
with other schools.
Likewise, NRI's
instruments are a cut above
the average, including a 31/2
digit precision digital
multimeter, triggered sweep 5"
oscilloscope, and integrated
circuit TV pattern generator.
They're top professional
quality, designed to give
you years of reliable service.
You can pay up to $800 more
for a similar course and not get
a nickel's worth extra in
training and equipment.
V
I;
,RI
Widest Choice of
Courses and Careers.
NRI doesn't stop with just one
course in TV/Audio servicing.
You can pick from five
different courses (including an
advanced color course for
practicing technicians) so you
can fit your training to your
needs and your budget. Or,
you can go into Computer
Technology, learning on a real,
digital computer you build
yourself. Communications
with famous Johnson
transceiver. Aircraft or Marine
Electronics. Mobile radio,
and more.
Free Catalog...
No Salesman Will Call.
Send the postage -paid card
for our free color catalog
showing details on all NRI
electronics courses. Lesson
plans, equipment, and career
opportunities are fully
described. Check card for
information on G.I. benefits.
No obligation, no salesman
will call. Mail today and see
for yourself why the pros
select NRI two to one!
If card is missing, write to:
NRI SCHOOLS
A
McGraw -Hill Continuing Education Center
ri
3939 Wisconsin Avenue,
Washington, D.C. 20016
11
channels. A noise -cancelling microphone,
mobile mounting bracket, and external
power cord are supplied with the transceiver.
Igot
it free!
y1Me
too.
CIRCLE NO. 71 ON READER SERVICE CARD
JBL DECADE SERIES SPEAKER SYSTEM
New Products
Additional information on new products
covered in this section is available from
the manufacturers. Either circle the item's
code number on the Reader Service Card
inside the back cover or write to the manufacturer at the address given.
FISHER 4- CHANNEL RECEIVER
I, Dick Blake, sent off to the
Warehouse Sound Co. and quickly
received a full-color catalog of stereo
components and complete music sys-
tems. I testify that they carry every
major brand and offer super discounts! Furthermore, if you'll include $1 for postage, those great
people will also send either one of the
following: their new 64 -page catalog
of professional products for musicians, or the 1975 edition of the Music
Machine Almanac, which is a 185 -page
institutional guide to stereo equipment, complete with photos, prices,
and specifications for over 40 brands!
Sells on the newsstands for $1.95
so
it's a good deal. Do it today!
-
WAREHOUSE SOUND CO.
BOX S SAN LUIS OBISPO
CA. 93405 (805) 543 -2330
:1R
óV
-5I.NLD
C
Railroad Square, Box S
San Luis Obispo, CA. 93405
(805) 543 -2330
name
address
city /state
zip
The Fisher Studio Standard Model 334
4- channel receiver boasts 40 watts
rms /channel with all channels driven into
8 -ohm loads and an IHF power bandwidth
of 30 to 22,000 Hz at 1 percent IM and 0.8
percent THD. It features built -in SC) and
The Model L36 is a moderately -priced
three -way speaker system that incorporates some of the hardware that comprises
the JBL Century L100 and professional
Model 4311 Studio Monitor systems. The
L36 contains a 10 -in. (25.4-cm) woofer with
a 2.5 -lb (about
-kg) magnet, 5 -in.
(12.7 -cm) midrange driver, and a 1.4 -in.
(3.56 -cm) tweeter. Crossover frequencies
are at 1500 and 6000 Hz. Nominal impedance of the system is 8 ohms. Power
capacity is rated at 50 watts rms of con1
tinuous program material, requiring
10
watts rms minimum drive power. The enclosure uses a ducted -port design and
comes finished in natural oak with fabric
color options. The system measures 24 in.
by 13% in. by 131/2 in. (61 x 34.6 x 34.3 cm)
and weighs 45 Ibs (20.5 kg). Retail price is
$198.
CIRCLE NO. 72 ON READER SERVICE CARD
TECHNICS SPEAKER SYSTEM
Technics by Panasonic has introduced
series of speaker systems that includes bookshelf and floor- standing models. The top -of- the -line Model T -500 is a
a new
CD -4 decoding circuitry. Besides husky
power rating, the receiver also has a "joystick" channel -balance control, loudness
contour that is automatically disengaged
when the output level is raised, and a sensitive (2 -pV) tuner. If stereo operation is desired, the amplifiers can be "strapped" to
double the power per channel. Other fea-
tures include Baxandall -type tone controls, FM muting, tape monitoring circuitry,
output jacks for 4- channel recorders, tuning meter with Fisher's "Stereo Beacon,"
and an AM tuner.
CIRCLE NO 70 ON READER SERVICE CARD
PEARCE -SIMPSON CB TRANSCEIVER
The Puma 23B is a 23- channel AM mobile
CB rig (crystals supplied) from Pearce Simpson. Its S /r -f meter glows amber on
receive, red on transmit, and flashes bright
red when fully modulated. A switch permits
selection of r-f or PA output. The transmitter operates at the legal power limit. A
dual- conversion receiver with 0.5 -pV sensitivity, with a crystal filter for selectivity
and an automatic noise limiter, simplify the
task of receiving signals on the crowded
four -way, seven -driver system that features
a frequency response of 35 to 20,000 Hz
±3 dB and handles between 10 watts
minimum and 100 watts maximum program power. Frequencies up to 2000 Hz are
covered by two 10 -in. (25.4-cm) woofers, a
5 -in. (12.7 -cm) driver handles the midrange, and a pair of wide- dispersion tweeters take care of the highs. Frequencies
above 8000 Hz are reproduced by an angled super tweeter assembly composed of
two 2 -in. (5.1 -cm) transducers with a 180°
dispersion angle. Two -position level controls are provided for the midrange and
tweeter.
CIRCLE NO. 73 ON READER SERVICE CARD
Also enclosed
(check one)
is
$1.00 for:
CONWAY MASTERANGER
Professional Products Catalog
01975
Music Machine Almanac
K -2
12
The Model 639 Masteranger from Conway
is an unusually versatile multimeter that
covers 93 ranges and 11 parameters. It features a FET front end for dc volts, 100POPULAR ELECTRONICS
CMOS
40004E
40014E
40024E
40044E
40064E
40074E
40084E
40094E
40104E
40114E
40124E
40134E
40144E
40154E
40164E
40174E
40184E
40194E
40204E
40214E
40224E
40234E
40244E
40254E
40264E
40274E
40284E
40294E
40304E
40354E
40374E
40404E
40414E
40424E
40434E
40444E
40484E
40494E
40504E
40514E
40564E
40604E
40694E
40764E
Warebrm Generator Kit
XR205K Only $28.00
Here's a highly versatile lab
instrument at a fraction of
the cost of conventional unit.
Kit includes two XR205 IC's,
data & applications, PC board
(etched & drilled, ready for
55
S
.55
.60
5.90
3.90
.65
3.60
.95
1.20
.55
.55
1.40
3.80
3.80
1.15
2.95
3.20
1.30
4.20
3.80
2.95
.55
2.30
.55
9.90
1.85
2.95
5.40
1.25
1.80
4.00
4.70
3.35
2.95
assembly) and detailed instructions.
Audio Amps
LM3527. 6-15V, 1.151/V. 8E2
1.60
LM354A: 6 -27V, 2.80W, 8E2
TAA611812. 6-15V, 1.15W, 852
TAA621412: 6.27V, 1.40W. 8:2
T84641811: 6-18V, 2.20W, 452
764800: 5.30V, 4.70W. 852
TBA810AS. 4.20V. 2.50W 4R
TBA820: 3-16V, 0.75W. 422
TCA830. 5-20V, 2.00W, 4E2
TCA940. 6 -24V, 6.50W, 852
2.50
Power
SI -1010Y
SI -1025E
SI -1050E
ss
Schottky
ss
$.80
.80
SN74S02N
.80
SN74SO3N
SN74SO4N
.80
.80
SN74S08N
SN74S1ON
.80
.80
SN74S11N
SN74S2ON
.80
SN74S3ON
.80
.80
SN74S32N
SN74S4ON
.80
SN74S41N
.80
.80
SN74S64N
1.30
SN74S74N
SN74S85N
6.10
2.90
SN74S86N
SN74S112N 2.50
SN74S113N 1.50
SN74S133N 1.00
SN74S138N 4.50
SN74S139N 4.20
SN74S140N 1.00
SN74S151N 3.30
SN74S153N 3.30
SN74S154N 3.40
SN74S157N 3.00
SN74S158N 3.00
SN74S160N 6.60
SN74S161N 6.60
SN74S174N 4.75
SN74S175N 5.00
SN74S181N 12.50
SN74S189N 5.10
SN74S194N 4.40
SN74S195N 4.40
SN74S251N 4.20
SN74S253N 4.20
SN74S275N 3.20
SN74S258N 3.70
.90
SN74S260N
SN74S280N 5.70
SN74S289N 5.00
6.80
93510
6.80
93S16
3.50
93S21
3.20
93S22
3.70
93S48
NIGIi
SPEED TTL
74H00N
74H01N
74H04N
74H05N
74H08N
74H10N
74H11N
74H15N
74H2ON
74H40N
74H74N
.34
.49
.36
.38
.44
.44
.44
.38
.39
.36
1.70
2.20
4.40
LM331 N:
I! ßó
1UOmmVn4
lb1B 2000nA
Noise
52 20
1.5d8
=
FM Stereo
Demodulator
$3.90
HYBRID
Qe'E'AMPLIFIERS
1.35
1.35
SN74SOON
2.00
3.00
2.20
3.00
oP AMP
XR1310
2.95
2.95
1.50
5.40
3.50
4.95
.90
4.30
1.60
DUAL LOW
NOISE
RMS
10W
25W
50W
IHF
25W
65W
120W
Price
$
6.40
18.00
25.40
LED's
Voltage
.125 "dia.
RegulatOIS
LM100H
LM104H
LM105H
LM105F
LM109H
LM109K
LM200H
LM204H
LM205H
LM209H
LM209K
$
LM300N
LM304H
LM305H
LM305AH
LM305N
LM309H
LM309K
LM335
LM336
LM340-05K
LM340-06K
LM340 -081(
LM340.12K
LM340 -15K
LM340 -18K
LM723D
LM723CH
LM723CN
L129
L130
L131
5.50
6.50
5.10
8.50
9.50
6.30
3.80
4.70
3.00
3.50
3.70
.90
1.40
1.40
1.10
1.40
1.20
1.75
1.95
2.30
2.40
2.40
2.60
2.60
2.60
2.60
2.60
2.60
2.60
209
Watch
with liquid crystal display.
Beautiful, reliable & accurate. $149.00 plus $2.50
for shipping & handling.
$7.00
8.50
8.50
P2102
16.00
5.50
P3101
5.50
P31014
5.00
MM6560N
5.00
MM6561N
5.00
DM8599N
5.00
93403
3.90
.80
.75
1.50
1.50
1.50
Decoded Read
Write RAM
P1103
$7.50
I
iy
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ANCRONA CORPORATION.
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7400N
.18
.27
7401N
.23
7402N
.23
7403N
7404N
.25
7405N
.29
7406N
.42
7407N
.49
7408N
.24
7409N
.54
7410N
.24
7411N
.29
7412N
.51
7413N
.79
7414N
2.81
7416N
.47
7417N
.64
7420N
.25
7421N
.51
7423N
.49
7425N
.49
7426N
.49
7427N
.54
7428N
.51
7430N
.23
7432N
.29
7433N
.61
7437N
.49
7438N
.49
1.01
7439N
7440N
.23
7441AN 1.16
.99
7442N
1.14
7445N
7447N
1.39
7448N
1.29
7450N
.23
7451N
.29
7453N
.26
7454N
.26
7460N
.24
7470N
.31
7472N
.39
7473N
.47
7474N
.47
IJ
7475N
7476N
7480N
7481N
7482N
7483N
7484N
7485N
7486N
7489N
7490N
7491N
7492N
7493N
7493AN
7494N
7495N
7495AN
7496N
7497N
74100N
74105N
74107N
74108N
74109N
74110N
74111N
74114N
74115N
74118N
74119N
74121N
74122N
74123N
74125N
74126N
74128N
74132N
74136N
74141N
74145N
74147N
74148N
74150N
74151N
74152N
74153N
74154N
74155N
74156N
74157N
2.49 74158N
.49 74160N
2.99 74161N
.79 74162N
1.29
74163N
.84 74164N
.84 74165N
.86 74166N
1.29 74170N
.99 74173N
1.51
74174N
1.09 74175N
1.51
74176N
1.65 74177N
.54 74180N
.49 74181N
.91
74182N
.91
74184N
.71
74185N
.91
74190N
.91
74191N
.91
74192N
.91
74193N
.81
74194N
.59 74195N
.89 74196N
.96 74197N
1.39 74198N
1.39 74199N
1.21
74200N
2.05 74221N
.91
74251N
1.89 74278N
1.79 74279N
2.95 74293N
3.55 74298N
.79
.59
.66
1.21
1.01
1.01
3.01
1.14
.89
2.25
1.12
1.64
1.49
1.49
1.26
1.54
1.89
1.59
2.05
1.59
1.89
1.89
1.98
2.55
1.79
1.52
1.92
1.69
1.69
2.49
3.85
1.19
2.89
2.29
2.89
2.89
1.49
1.39
1.89
.99
2.39
2.39
2.59
4.48
5.05
1.75
1.75
2.95
.92
.92
2.55
NI
I
,i
LOW
34
.34
.39
.39
.34
.39
1.62
1.62
.34
.74
.89
1.62
1.74
1.62
1.50
1.60
3.40
1.80
2.80
4.20
1.80
1.70
3.20
3.50
1.50
1.80
2.80
3.70
INr'T£RFYraE
4.00
DM8820N
DM8820AN 6.50
4.50
DM8830N
5.00
DM8831N
5.00
DM8832N
1.30
9600
9621
2.00
3.00
3.00
4.50
3.00
3.50
3.00
.2O
Red
Power Regulators
LM335K: 5V, 600mA
LM336K: 12V, 500mA
LM337K: 15V, 450mA
2.40
3.50
3.60
Power Transistors
BU204
BU205
BU206
BÚ207
BÚ208
BU209
1300V
1500V
1700V
1300V
1500V
1700V
4.14
4.95
5.94
5.85
6.93
8.64
TECHNICAL LITERATURE
S.50 per item
Contains literature for all products
ANCRONA
City, CA. 90230
di
Yellow
.25
.30
.30
Green
Displa%s
SLA1
SLA11
SLA21
SLA2
SLA12
2.25
4.25
4.25
Red
2.25
Green 2.25
2.25
7.50
Red
7.50
Red
Red
Green
±1
±1
SLA22
SLA3
SLA4
Optoisolator
MCT2
1.45
Linear ICs
LM301A
LM301AM
LM301AN
LM302H
LM302N
LM306H
LM307H
LM307M
LM306H
LM308AH
LM310H
LM311H
LM318H
LM555CM
LM709CH
LM709CN
LM71OCH
LM71OCN
LM725CH
LM733CH
LM733CN
LM741CH
LM741CM
LM747CH
LM747CN
LM748CN
LM3046CN
LM3054CN
5.90
TO -5
Mini -dip
Dip
.75
1.10
.95
1.40
Dip
TO -5
2.80
TO -5
.90
Mini -dip
.90
TO -5
1.20
5.00
TO -5
1.40
TO.5
1.70
TO -5
TO -5
2.50
Mini -dip
.95
TO -5
.45
.45
Dip
TO -5
.60
.75
Dip
5.00
TO -5
1.50
TO-5
1.50
Dip
TO -5
.45
.44
Mini -dip
1.90
TO -5
.90
Dip
.40
Dip
.95
Dip
1.50
Dip
TO -5
Phase Locked Loops
Mini-dip 2.00
IC sockets
8
Interdesign 1101: 0.111z-2MHz,
0-5V Output, var. width, line or
battery operation. $159.00.
SALES TAX: California residents add 6 %; Canadian
residents add 12% federal sales tax, and add 5% in B.C.
O. Box 2208P, Culver
Green
LM567CM
PULSE GENERATOR
4.00
4.20
6.50
6.50
3.00
2.70
MIN. ORDER
$10.00
1.30
9601
9602
9614
9615
9616
9617
9620
SEND CHECK OR MONEY ORDER (NO. C.O.D.) TO:
P.
tt
COMPVT£R
POWER TTL
74L00N
74L02N
74L03N
74L04N
74L10N
74L20N
74L42N
74L47N
74L51N
74L73N
74L74N
74L90N
74L93N
74L95N
93L00
93L01
93L08
93L09
93L10
93L 11
93L12
93L14
93L16
93L18
93L21
93L22
93L24
93L28
93L34
93L 38
93L40
93L41
93L60
93L66
f
`1
.25
.30
.30
Red
Yellow
220
220
220
Memories
P11014
P110141
P14024
a
/TINI TTL
216
216
216
Digital
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TO -5
TO -5
TO-5
TO
.55
.65
.90
1.10
1.40
5
Shift Registers
1402A
1403A
1404A
1405A
1406
1407
1506
1507
2505K
2512K
2524V
2525V
2807
2808
TMS3114
MM5055N
MM5056H
MM5057N
S
8.50
6.00
6.00
4.50
6.00
6.00
3.00
3.00
4.00
5.50
4.00
5.50
4.00
5.50
8.20
5.00
5.00
5.00
.69
NOVEMBER 1974
13
In
d
ible.
How else would you describe a
preamplifier with:
A Peak Unlimiter that restores
dynamics lost in recording to
closely approximate the original.
A Downward Expander that reads
"gain riding" and expands
dynamics down to precisely the
intended level.
An AutoCorrelatbr that makes
record /tape hiss and FM broadcast
noise virtually vanish without
affecting musical content.
Plus an Active Equalizer that gives
you flat energy distribution over
the full audio spectrum, Joystick
Balance and Step Tone Controls
that allow precise music tailoring
to your listening environment and
SQ* and Phase Linear differential
logic for Quad Sound.
megohms input impedance, and an exceptionally large mirrored meter movement
scale. Although the instrument is designed
to be battery operated, an accessory power
supply permits line operation. With optional probes, ranges are further extended,
and they permit r-f voltage and temperature to be measured. A zero scale permits
null detection and galvanometer operation. The tester can also be used for incircuit resistance checks on semiconductors without damaging them. Accuracy is claimed to range from -±1.5 percent
for ac and dc voltages up to 1500 volts to ±5
percent for r -f. R -f, HV, and peak -to -peak
probes, external high- current shunt, ac
power supply, capacitive HF voltage divider, and temperature probe are available
as optional accessories.
CIRCLE NO. 74 ON READER SERVICE CARD
JERMYN DUAL-TRACE 10 -MHZ SCOPE
The dual -trace Scopex Model 4D -10 oscilloscope from Jermyn features 10 mV /cm
sensitivity and a dc to 10 -MHz bandwidth.
The all- solid -state circuitry includes MOS
devices. Direct calibration is in V /cm and
LAFAYETTE DOLBY CASSETTE DECK
Lafayette Radio Electronics' new No.
99- 16156W stereo cassette deck features
built-in Dolby noise reduction circuitry.
A
three -position bias switch is provided for
adjusting equalization for standard and
high- output ferric -oxide and chromium dioxide tape formulations. Other features
include dual VU meters, slide controls for
microphone and line inputs and line outputs, three -digit tape counter with reset
button, memory rewind, and total automatic mechanism shutoff. The deck is capable
of performing sound -with -sound mixing.
Frequency response is 30- 12,000 Hz ±3 dB
at 20 dB below 0 VU. S/N is rated at 49 dB
(59dBwith Dolby circuit switched in). Wow
and flutter is 0.12 percent. Retail price is
$239.95.
CIRCLE NO. 76 ON READER SERVICE CARD
LECTROTECH COLOR SIGNAL GENERATOR
The compact Model BG -10 color signal
generator from Lectrotech, Inc., is small
enough to fit into a shirt pocket. Yet, it is a
full- function instrument that provides
s /cm. A
The 4000 is an advanced stereo
preamp that actually puts back in
what recording studios take out ...
lets your music (at last) reach life-like
levels without distortion ... lets you
(for the first time) hear your music
from a silent background. It is, in a
word, incredible. Ask your dealer
for an audition.
Price: $599
Cabinet: $37
Warranty: 3 years, parts & labor.
THE POWERFUL DIFFERENCE
PHASE LINEAR CORPORATION
P.O. Box 1335 Lynnwood, Wash.
98036
*SQ is a trademark of CBS Labs, Inc.
CIRCLE NO. 45 ON READERS SERVICE CARD
14
horizontal control incorporates a
x5 expansion function that holds the trace
under observation in the display when activated. Triggering is regulated by a single
control that governs both level and polarity. In the absence of a trigger signal, the
trace operates in the free-running mode.
All other controls are pushbutton and chop
modes, external trigger, and ac and dc
coupling. Price of the scope is $450.
crosshatch, dots, single horizontal /vertical
lines, center -screen dot, and three- and
10 -bar color test patterns. The 10 -oz
(283.5-g) instrument employs CMOS LSI
chips for all counting functions for minimal
drain from inexpensive 9-volt transistor
batteries. The generator's r-f output is on
TV Channel 4 or 5. Overall size is 51/2 in. by 3
in. by 11/B in. (14 x 7.6 x 2.9 cm). List price is
$89.50.
CIRCLE NO. 77 ON READER SERVICE CARD
CIRCLE NO. 75 ON READER SERVICE CARD
INSTANT BREADBOARDING
HEATH TELEPHONE AMPLIFIER
The Heathkit Model GD -1024 telephone
amplifier kit makes it possible to carry on a
conversation without being tied to the
phone or to conduct "conference" calls
with many individuals participating in one
location. The amplifier operates with virtually any type of telephone instrument. To
use it, the handset of the telephone instrument is placed on the amplifier's cradle.
The incoming signal is then acoustically
coupled to the amplifier where it undergoes amplification and is reproduced by
the amplifier's speaker. Volume can be adjusted to suit the listening area. Other features include all solid -state circuitry for low
no- signal load, 8 -ft (2.44 -m) speaker cord
to reduce feedback, and low -cost battery
operation. Mail -order price is $14.95.
CIRCLE NO.
5 ON
READER SERVICE CARD
Instant Instruments, Inc., has developed
Instant Circuit Breadboarding for the designer who requires a fast, simple, low -cost
method of transferring his ideas from
paper to wired electronics. This simple
breadboarding method is said to allow instant assembly of a prototype circuit without drilling or insertion of components,
cutting pc boards, or installing jumpers as
required in conventional systems. The designer solders to pre- etched component
pads. Both boards and components are
easily salvaged for reuse. Four basic patterns are available for discrete components and IC's. All have pre -punched front
panels. All patterns are solder -plated to
prevent oxidation and to give good
copper -to- solder connection bonds.
Prices range from $2 to $8.60.
CIRCLE NO. 78 ON READER SERVICE CARD
POPULAR ELECTRONICS
MARK TEN
B,
THE GAS SAVING, PLUG SAVING,
TUNE-UP SAVING, ELECTRONIC.
IGNITION FROM DELTA.
NOW AS LOW AS $49.95.
Years of testing
and use by race
ca- drivers in all
categories have
proven Delta's
Mark Ten B the
most advanced
ignition system
on the market today.
Prove it to yourself. Give you car vr0000m!
With a Mark Ten B Capacitive Discharge Ignition System under -he hood of your ca- great
things will happen ... like reducing costly
tune -ups by as much as 75 %. Further, you get
beaer all- weather starts, quicker acceleration
and better mileage.
Many operatioral problems caused by
emission control devices, poo- manifolding or
improper fuel miXtures disappear. Delta's
Mark Ten B even mproves the performance
of brand -new factory installed elec -ronic
igr itions (Chrysler and Ford). Factory systems
merely eliminate points and condenser, but
the Delta Mark Ten B combines the advantaces of capacitive discharge with solid state
electronics to
give real performance and
increased
energy.
Are you a doit- yourselfer''
BLild your own
Mark Ten B... it's
available in low -cos:
kit form. Or, if you prefer,
get the complete ready -to- install
unit. Either way, you can install is
ycurself in minutes with no rewiring, even
oNer Chrysler and Ford systems.
Mail the coupon today and discover how to
er joy happy motoring with Delta's Mark Ten
B. The do- it- yourselfer's dream that really
pays off.
19
DELTA
UD
P.O. Box 1147. Dept. PE
303 -242 -9000
C,
INC.
Grand Junction. Colo. 81501
Please send me free literature.
Mark Ten B assemEnclosed is $
Ship C.C.D. Please send:
Ship ppd.
_
StanMark Ten B Kit @ $49.95 ppd. (12 volt negative ground only
bled @ $64.95 ppd.
12 Volt: Specify
__ 6 Volt: Neg. Ground Only
dard Mark Ten assembled, @ $49.95 ppd.
Pos. Ground
Neg. Ground
Standard Mark Ten DeltakitR @ $34.95 ppd.
(12 Volt Positive or Negative Ground Only)
i
Car Year
Make
Name
Address
City /State
NOVEMBER 1974
Zip
CIRCLE NIO. 12 ON READERS SERVICE CARD
15
Incomparable!
Incomparable is not
New Literature
a
term to take lightly. In test
after test the Mark IB
Stereo Preamplifier and
Mark IIICM Stereo Power
Amplifier have led the industry in every respect. At
SAE, engineering excellence is not a goal, it's a
reality! See the Mark IB
and Mark IIICM at your
nearest SAE authorized
dealer.
ALTEC ENCLOSURE DESIGN MANUAL
"Loudspeaker Enclosures-Their Design
and Use" is a well -illustrated 32-page publication for the do- it-yourself audio enthusiast. It is a rich source of information to
aid in the design and construction of systems of predictable and satisfactory performance. Topics include the function of
the enclosure, loudspeaker design theory,
and types of enclosures-from infinite baffles to base reflex enclosures to tuning the
bass reflex port. Details on selection of
materials are abundant -types of board,
acoustic damping material, stiffeners, and
grille material. Other useful information includes a chart of common sound pressure
levels, frequency ranges of musical instruments, and a glossary of audio terms.
Available for $2 from Altec Corp, 1515 S.
Manchester, Anaheim, CA 92803.
n
SAE, Inc., Dept. PE 11/74
P.O. Box 60271, Termina Annex,
Los Angeles, California 90060
Gentlemen:
Please rush free information on the Mark IB Stereo
Preamplifier and Mark 111CM Stereo Power Amplifier by
return mail.
Name
Address
City
Zip
State
ELPA TAPE RECORDER TESTING BOOKLET
CIRCLE NO. 34 ON READERS SERVICE CARD
Inside each of our 4- channel cartridges
AT12S
AT15S $100.00
$64.95
AT2OSL
$'75.:0
AT14S
$75.00
"Tape Recorder Clinic Procedures" offered by Elpa Marketing is a 21 -page booklet that describes the step -by-step methods
for conducting a tape -recorder test clinic
using the Ferrograph Ferrotester. The
booklet lists sources from which test tapes
are available and includes a sample Tape
Recorder Clinic Test Report sheet. Address: Elpa Marketing Industries, Inc., Tho rens & Atlantic Aves., New Hyde Park, NY
11040.
VACTEC PHOTOTRANSISTOR
BULLETIN
A bulletin featuring the company's com-
lurks a Dual Magnet stereo cartridge
waiting to please you.
Our sophisticated four -channel
cartridges* are also stereo cartridges
at heart. Very good ones. With ruler
flat response, outstanding stereo separation (especially above kHz where
1
it counts), and truly impressive high
frequency tracking.
All these advantages are as important
to good stereo as they are essential
to CD -4. And they can be achieved
only by pay ng very close attention to
detail. And .sing only the best. Like a
genuine St batat stylus. Nothing less.
The results are good for any reco-d ..
whether stereo. matrix, or discrete 4channeL But you should really hear
for yourself. Write today for our dealer
list. No natter how many channels
you wart to hear best.
16
CIRCLE NO.
3
33
63043.
.
"J.S. Pat. Nos: 3,720,796; 3,761,647
fSiibata stylus Pat. No. 3,774,918
audio technica.
AUDIO -TECHNICA U.S., INC., Dept.
In Canada: Superior Electronics, Inc.
plete line of phototransistors and photo Darlingtons is available from Vactec. The
8 -page No. VTTA-1 bulletin describes the
two basic chip sizes and various packaging
configurations. In addition to mechanical
data, it also covers electro- optical
parameters and provides 24 graphs of
characteristics and environmental information. Address: Vactec, Inc., 2423 North line Industrial Blvd., Maryland Hts., MO
Shiawassee Ava. Fairlarn, Ohio 44313
ON READERS SERVICE CARD
STANCOR TRANSFORMER CATALOG
The new Stancor Transformer Catalog (No.
407) available from Essex Controls, lists
1600 standard transformers and gives full
technical data;mounting dimensions, and
other specifications on the company's
complete line of audio and power transformers and chokes and inductors. Address: Essex Int'I., Inc., Controls Div., Stan cor Prods., 3501 W. Addison St., Chicago,
IL 60618.
POPULAR ELECTRONICS
INCREASE GAS MILEAGE
iryA Hobby Scene
Voltage Warning Device
like some type of warning
device that will alert me in the event
the dc voltage from my bench power
supply exceeds some predetermined
level. I am looking for something simple that can be put together quickly.
Q.1 would
A. The circuit shown here is a zenercontrolled relay. Select the zener
10 -20%
INSTALL A
BAY
CAPACITIVE
DISCHARGE
IGNITION
SYSTEM!
$23.88
$28.88 with
By.Pass Switch as Pictured
switch is closed and power is applied
to the system, the capacitor starts to
charge through the 1- megohm resistor. When the voltage at the emitter of
the UJT reaches the firing potential of
the UJT used, a positive spike will appear at the gate of the SCR, at which
point the SCR fires. Because the circuit employs only dc voltages, the
SCR will remain conducting until the
power switch is opened.
FIELD-TESTED FOR 5 YEARS!
Increase Engine Power
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Instant Starting in Ali Climates
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NO FINER CD SYSTEM AVAILABLE!
Completely wired, readtoinstall not a kit
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Distributor points last lifetime of car
Spark Plugs last 3 to 10 limes longer
For 12-von negative ground systems only
-year written guarantee
1
Write For Quantity Purchase Prices
rally
PRODUCTS Division of V.1 Products, Inc.
P.O. BOX 9562, HOUSTON. TEXAS 77011
Electronic Door Bell
Model 115 CD ignd no
Please send
Systems with By-Pass Switch @ 528.88
Sw10l CD ignitwn
Please send
_ Model
Systems without By Pass Switch @ 523.88
Enclosed is S
plus SI per und
for shipping.
repaired my front doorbell
so many times that I'm getting fed up
with it. Isn't there some simple electronic substitute for the mechanical
buzzer?
Q. I have
diode for the maximum voltage you
want from your power supply. Then
A. There are many oscillator circuits
use a relay whose coil current is simithat will deliver a pleasant sounding
lar to the zener current of the diode.
When the voltage is below the zener
7'9-f/SY
point, nothing happens. But when the
voltage exceeds the zener diode's
breakdown voltage, the relay will
energize and trigger on the external rF
alarm connected across the relay's
20K
contacts. The relay will remain on for
all voltages above the zener point, and
will immediately drop out at voltages
0/ID/Y/01/AL TOMES)
below the zener point.
Name
Address
City/ State
zip
CIRCLE NO. 43 ON READERS SERVICE CARD
/K
OISOn
Catalog
Alarm Delay Circuit
circuit for my
car that will arm an intruder alarm a
minute or so after I leave the vehicle.
It must work on dc and use a minimum
Q.1 need a time -delay
of parts.
WITH
VALUE PACKED OF
THOUSANDS
BARGAINS
ELECTRONIC
68K
We Will Send You The
Next 7 Issues FREE!
A. The simple timer circuit shown here
should suit your needs. When the
You'll Find The Best
Of the Name Brands
Plus Exclusive
Olson Products at
Low, Low Prices!
tone when a switch is closed. The one
shown here uses a pair of transistors
and as many switches as you wish.
Each switch is associated with its own
tone -control potentiometer so you
can adjust each one differently. If you
don't have a high- impedance speaker,
try an ordinary transistor output transformer and speaker. Any general purpose transistors can be used.
NOVEMBER 1974
FREE
Send
Today
Olson Electronics Dept. iz
260 S. Forge St., Akron. Ohio 44327
Name
Street
City
State
\
Zip
Apt. No
CIRCLE NO. 29 ON READERS SERVICE CARD
17
It you can use
any of these
toois
You can gain exciting new skills
ls
an electronics troubleshooter in
Bell & Howell Schools' fascinating learn-at -home program that
includes building and experimenting
with the new generation color IV.
You may already have some of
the skills you need.
Most of us at one time or another
have put a screwdriver, a pair of pliers or
some other basic tool to work. Fixing a
bicycle wheel, tightening a window latch,
putting up a bookshelf, or what have you.
But here's a thought.
Using these same simple tools as
a starting point, you can develop the
ability to put them to work for you in far
more ways than you ever dreamed of. And
Bell & Howell Schools' fascinating home
learning adventure in electronics will show
you how.
These days when it seems like
there's an "electronic everything," it
makes good sense to have occupational
skills in the servicing and repair of such
products as TV's and other home electronic
equipment. If you're a person who
recognizes a future in this field, Bell &Howell
Schools is ready to help you develop
the specialized ability you need to
become an electronics troubleshooter.
While no assurance of income or
employment can be offered, we can
assure you that no better at -home training
in electronics is available anywhere.
We have an exciting way for you
to pick up these specialized skills in your
spare time.
Don't think for a moment that we
want you to spend your off -hours just
reading a bunch of "how -to" books. That
would bore anyone after awhile. What we at
Bell & Howell Schools offer is the modern
way to learn ... a very different approach
from the way you've been used to.
18
POPULAR ELECTRONICS
First of all, we believe that when
you're exploring a field as fascinating as
electronics, reading about it is just not
enough. That's why throughout this
learning adventure you'll get lots of "hands
on" experience with some of the latest
electronic training tools available today.
You'll test and experiment with them and
gain exciting new skills all along the way.
Once you've completed this
program a number of directions are open
to you:
1. Use your training to seek out a job in
the electronics industry.
2. Use your training to upgrade your
current job.
3. Use your training as a foundation for
advanced programs in electronics.
4. Use your training in a business of your
own -a few of our graduates are even
doing this now!
No electronics background
necessary.
That's one of the many attractions
of this program. We start you off with the
basics and help you work your way up one
step at a time. As a matter of fact, with your
very first lesson you receive a special Lab
Starter Kit to give you immediate working
experience on equipment as you are picking
up the fundamentals.
to home entertainment.
You'll probe into the technology
behind all- electronic tuning and into the
digital circuitry of channel numbers that
You'll build and perform exciting
appear big and clear, right on the screen!
experiments with Bell & Howell's ElectroYou'll also build -in a
Lab electronics training
remarkable on- the -screen
system.
digital clock, that will flash
You build the
the time in hours, minutes
Electro -Lab step-by -step,
and seconds. Your new skills
too. First, the design
will enable you to
console. After you assemble
he
men
Channel number, that fl.l.
program a special autoit, you'll be able to set up
matic channel selector to
and examine circuits
skip over "dead" channels
without having to solder
and go directly to the
them in place.
Next, you'll enjoy
channels of your choice.
You'll also gain a
building a digital multimeter.
On-screen ägrt.i
better understanding of the
This important instrument
exceptional color clarity of
measures voltage, current
the Black Matrix picture
and resistance and displays
tube, as well as a working
its findings in big, clear
knowledge of "state of the
numbers like on a digital
art" integrated circuitry and
clock. Far easier to read
the 100% solid -state chassis.
than "needle pointer"
Automatic We -set channel selector
Having actually
meters.
built and experimented with this TV, you'll
Then comes the solid -state
come away equipped with the kinds of
"triggered sweep" oscilloscope which is
skills that could put you ahead of the field
similar in principle to the kind used in
in electronics know -how.
hospital operating rooms to monitor
heartbeats. You'll use it to analyze tiny
We try to give more personal
integrated circuits. The "triggered sweep"
attention than other learn -at -home
feature locks in signals for easier
programs.
observation.
1. Toll -free phone -in assistance. The
You'll actually build and
program is designed so that you can
work with Bell & Howell's new
proceed through it smoothly, step -bygeneration color TV...
step. However, should you ever run into
investigating features you've
a rough spot, we'll be there to help.
probably never seen before!
Many schools make you mail in all your
This 25" diagonal color
questions. We have a toll -free line you
TV has digital features that are
can call when you have a question that
likely to appear on all TV's of the
can't wait.
future. Features made possible
2. In- person "help sessions." These are
by the applications
held in 50 major cities at various times
of digital electronics
throughout the year where you can
talk shop with your instructors and
fellow students.
Why wait?
Find out more on how you
can pick up new skills in electronics
troubleshooting as you work with Bell &
Howell's new generation color TV. You've
got the tools to do it!
It makes the learning process faster and
certainly a lot more interesting.
ArwaimmemstalmesseaseemoNIMIMMINIF
Mail the postage -paid card today
for full details, free!
Taken for vocational purposes,
this program is approved by the state
approval agency for Veterans Benefits.
If card has been removed, please write to:
An Electronics Home Study School
DEVRV InSTITUTE OF TECHfOLOGV
BELL
Ei
HOWELL SCHOOLS
i,.a.t,,,.11Va<k.,on,al in
fk91
r. Howell t-rxnikan,
NOVEMBER 1974
21
cirri
.
This is what evidently takes place.
An amplifier called upon to operate at
its limits much of the time will clip frequently, squaring off the tops and bottoms of any waveforms it can't pass.
Stereo Scene
By Ralph Hodges
BLAZING SPEAKERS
HAVE you blown out any good
loudspeakers lately? The ques-
tion is not frivolous, because the factory return rates for many high -quality
speaker systems, certified safe for
loud home listening, are apparently on
the rise. Manufacturers have even
begun encouraging the press to print
more stories about loudspeaker failure, presumably in the hope of educating the consumer and forestalling disaster. The trouble is, such stories have
a way of growing into "pageants," to
use the word of one company
spokesman. Although most speaker
blow -outs result from
causation -an attempt
a
simple
on the
speaker's part to absorb more electrical energy than is good for it
is next
to impossible to be both exhaustive
and concise about all the ways in
which this can happen. There are
-it
FUNDAMENTAL
THIRD HARMONIC
FIFTH HARMONIC
more, it seems, than meet the eye
(figuratively) or the ear (literally).
Big Amps and Small.
One cause of
speaker failure is obvious, you'd think:
the proliferation of super -power amplifiers. And yes, I'm sure there are and
will continue to be those who overpower their systems into occasional
attacks of silence, although the likelihood is that this comes about most
often through accidental signals
loose ground connection, a severe
-a
switching transient, a dropped tone
arm, or even (as used to plague rock
groups when setting up) a sudden
outbreak of acoustic feedback to the
microphones when no one can get to
the controls in time to save the situation. Now and again someone does
destroy a speaker by playing loud
music through it. But since the
speaker almost certainly exhibited
audible signs of distress before succumbing, he usually can't say that he
wasn't warned.
Excessive amplifier power isn't always to blame, however. From the
latest reports, one of the serious and
growing problems is the blowing out
of speakers by under-powered amplifiers. This was first brought to my attention in an article by Peter Mitchell,
who among other distinctions is the
president of the Boston Audio Society.
His written explanation was so plausible in a theoretical sense that was
first tempted to think the whole business was just that: a theoretical possibility that doesn't occur much in real
life. A few phone calls to manufacturers set me straight. It's not a rarity.
Naturally, the resulting customer unhappiness is worse, as a rule, than
when one of the super -power afficionados does his direful deed. The
under-powered customer, you see,
thought he was taking pains to stay
within the power limitations specified
by the speaker manufacturer, and yet
he still got into trouble.
According to waveform analysis,
these flat tops and bottoms represent
odd -order harmonics of a sine-wave
fundamental: i.e., spurious high frequencies of significant amplitude (see
Figs. 1 and 2). These harmonics -and
some of them can be very high in
frequency-get routed to the tweeter,
which has to cope with them in some
way. If clipping is frequent, the tweeter
has an almost continuous input of distortion products to handle. In time its
relatively fragile voice coil, given no
chance to cool off, shorts, or opens
up, and that's it.
The putative problem here is that
there's more (and more frequent)
high- frequency energy in the clipping
distortion than in most music, and
therefore more energy than the
tweeter's designer anticipated its having to take. Of course, you wouldn't
expect the distortion to sound too
good. But perhaps, if it were high
enough in frequency, and if the recording had a typically hard, wiry top
end and a continuous background of
high -hat cymbal, it wouldn't be especially annoying. In any case, it evidently happens, as the man says, and
audiophiles are advised to give a close
listen to the high frequencies
whenever they run their systems up
near maximum levels to make sure
things don't sound worse than they
should. This is a particularly good idea
with pop music having heavily compressed dynamics, since a constant
level means constant clipping when
the amplifier is operating at its design
limits.
I
w
RESULTANT
I-
a
á
3
5
FREQUENCY IN OCTAVES
Fig. 1. Sine -wave fundamental
with two harmonics results
in a waveform approaching a
square wave, which ideally
would have an infinite series
of odd-order harmonids.
22
FREQUENCY
IN
OCTAVES
Fig. 2. Part of the spectrum
for a perfect square wave.
POPULAR ELECTRONICS
r
Monitor 9 or any
channel you choose
Scan Alert signals you
when there is
transmission on channel
9 (can be field- modified
to any channel), then
lets you immediately
transmit on 9 without
CB /PA switch
lets you drive a
PA horn
changing channel selector
Switchable Noise Blanking
or Noise Limiting
CuBR
NB
Transmit
light shows
you're on the
air
28
PA
SCAN
e
CB
G`e
EMERGENCY CH
Channel 9
signal light
Volume control
Squelch control with threshold
adjustable below 1;,V
MAXIMUM LEGAL
POWER PLUS...
Convenient plug -in microphone,
output for extension speaker and
the rugged quality and precision
that COBRA is famous for! Send
for your copy of our detailed full
color brochure today!
PRODUCT OF DYNASCAN CORPORATION
HOLD
Illuminated
meter
Large
illuminated
channel
selector
Delta Tune helps
you tune in off frequency signals
cobra 28
1801 W. Belle Plaine
Chicago, Ill. 60613
o
CIRCLE NO. 9 ON READERS SERVICE CARD
NOVEMBER 1974
23
COLLECTORS!
Here's how to enjoy
Old-Time Radios -
A
fascinating hobby!
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COLLECTORS!
Bandwidth.
If excessive amplifier
power is sometimes a problem, excessive amplifier frequency response
(bandwidth) can be worse. Now and
again a speaker manufacturer will
refer nostalgically to the carefree days
when amplifiers had output transformers, those wonderful low -pass filters that blocked dc and never let anything much higher in frequency than
the ear could hear (and sometimes not
even that much) get through to the
speakers.
Today it almost seems as if many
transistorized amplifiers have power
responses from dc to practically infinity. Occasionally a defective unit is
found with so much ultrasonic oscillation running around inside that it almost violates the FCC's regulations on
illegal r -f radiation. Ultrasonic stuff,
particularly when it's a constant,
steady -state signal, is extremely hard
on tweeters. At some high frequency
the mass of any tweeter will prevent
it-or at least parts of it -from moving
in response to the signal. This means
that the entire input is converted into
heat; being unable to move, the voice
coil doesn't even have the benefit of
the circulating currents of cooling air
that are set up to some extent during
normal operation. Recently, heard of
a case in which an amplifier so afflicted, when hooked up to speakers of
extremely high power -handling capability, wiped out all the tweeters before
the music even had a chance to start.
The preventive measure you should
take here-and I've been observing it
ever since the big, wide -bandwidth
amplifiers started to arrive -is to connect up the oscilloscope before you
connect up the speakers. This will enable one to check for ultrasonic output, and also to inspect any low frequency turn -on pulses. It's best to
have the rest of the system hooked up
too, since certain combinations of
components seem occasionally able
to set up oscillations that other combinations avoid.
Most woofers today are quite sturdy,
physically and electronically. You've
got to be in a position to deliver really
brutal amounts of power to them before they'll sustain much damage.
Still, this is a possibility that must be
considered. have not heard lately of
any woofers being hurt by record
warps and such perturbations, although the amount of subsonic
energy they can generate is sometimes startling. But amplifier misbehavior is another subject.
I
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Any decent amplifier should be stable within the limits of its power output capabilities, and even beyond
them. And yet stories persist about
certain designs that are believed to
produce horrendous, speaker -destroying pulses of subsonic energy
when overdriven, presented with an
unfortunate type of speaker load, or
otherwise mistreated. True enough,
some early amplifiers were subsonic ally unstable, and probably the remembrance of them feeds the fires of
suspicion about modern units. Furthermore, there are undoubtedly
numerous cases of amplifier defects
that have caused strange, unpredictable signals to appear at the outputs.
But from what I've been able to learn,
no such misbehavior can clearly be
attributed to any of the modern, popular models. Speakers are returned to
their manufacturers daily with the
woofer voice coils torn out by the
roots, among other sorts of mayhem.
But it's rarely possible to tell whether
the blame lies with the amplifier or the
user.
Needless to say, an amplifier would
have to be a big one to destroy a
woofer in such dramatic fashion.
Cautionary notes are always in order
with high -power amplifiers. Whether
he suspects trouble or not, it's probably a good idea for any owner of one to
spend an evening listening with the
speaker grilles off, just to familiarize
himself with the degrees of excursion
the woofer cones routinely go
through.
Another point worth discussing is
the matter of dc voltages (or dc "offsets") that may appear at the output
capacitors. In a paper presented several years ago, Kerry Gaulder, who
has served in design and engineering
capacities with several major companies, treated this subject at length.
An amplifier with dc offset will, of
course, produce a constant current
through the woofer voice coil. But this
source of voice -coil heating is rarely of
sufficient magnitude to concern anyone. What is problematic, according
to Gaulder, is the possibility of serious woofer -cone offset. In other
words, the dc current displaces the
voice coil in the magnetic gap (either
forward or back, depending on polarity), so that it is approaching the limits
of its excursion in one direction, even
when it's not reproducing any sound
and is presumably at rest.
If this theoretical possibility is true,
acoustic -suspension woofers might
CIRCLE NO. 28 ON READERS SERVICE CARD
24
POPULAR ELECTRONICS
be more susceptible to this effect than
others. Whereas other woofers have
relatively springy mechanical suspen-
sions that resist offset, acoustic suspension designs depend largely on
the air cushion within their sealed enclosures to restore the voice coil to its
proper "rest" position. Slow leaks in
the enclosure could cause air pressures within and without the enclosures to be equalized, after a time, for
any position the woofer cone cares to
assume, and that becomes the new
"rest" position. But theory aside,
have no in- practice facts to support
such a supposition.
Avoice coil offset significantly in the
rearward direction is in danger of
striking the bottom of the magnetic
gap with even moderate low -frequency signals. Aside from the distortion and noise generated, this may
do no immediate harm. But in time the
edge of the voice -coil former (usually
cardboard) may become flattened or
turned over so that it can no longer
clear the magnetic gap freely. An offset in the forward direction may
launch the voice coil out of the gap
entirely when a strong signal comes
along, and a safe return cannot be
guaranteed. Both these mishaps may
I
a woofer is overpowerful amplifier, but
driven
voice -coil offset greatly increases the
probability.
Intrigued by Gaulder's paper, managed to dig up a direct -coupled amplifier with a relatively high dc offset on
one channel. (Gaulder suggests 25
millivolts as the maximum permissible
value.) After letting it work over an
acoustic -suspension speaker with
some pipe -organ music for about an
hour, measured the offset as 0.16 volt
also occur when
by a
I
I
across 4 ohms (the dc resistance of
the speaker system). Despite this unacceptable voltage was unable to detect any displacement of the woofer
cone after the ordeal, which may
prove something or nothing. My inclination is to defer to Gaulder's greater
experience in this area, and so suggest you pay some attention to dc
voltages when present. Many amplifier manufacturers now routinely
specify permissible offset values, and
others would probably give you the
figures they allow if requested.
I
I
TIM. Some investigations are curnew type of
amplifier distortion -"new" in the
sense that it hasn't been seriously
rently being made into
a
studied or quantified up to now. It
goes by the name of transient intermodulation distortion or TIM. Its
cause appears to be lateness of the
negative feedback signal in getting
back to its assigned earlier stage of
amplification and engaging properly
the signal being processed. The effect
is too brief to be detected by conven-
tional distortion measuring techniques with steady -state test signals, it
is said. But, in effect, what happens is
that the initial onset of an abrupt new
signal within the amplifier (a transient,
in other words) gets through without
being correctly processed by negative
feedback. This results not only in the
feedback's failing to do its distortion compensating job, but also in possible
overload of subsequent amplifier
stages.
don't understand all the aspects of
TIM, or even whether it is the problem
it's been trumped up to be. But if it is,
indications point to the generation of
I
large amounts of high- frequency
energy and the existence of frequent
overload conditions within the amplifier. (Perhaps should point out here
that some amplifiers are considered to
be more subject to TIM than others.)
I
There's really no reason to suspect
OttiC
(
le
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CIRCLE NO. 42 ON READERS SERVICE CARD
NOVEMBER 1974
25
that it's directly responsible for any
kind of speaker failure, since its duration is so brief. However, all the results
are not in as yet. Readers interested in
pursuing the subject further should
consult the papers by Dr. Matti Otala in
past issues of the Journal of the Audio
Engineering Society.
The Stitch in Time. The readiest
protection you can give a speaker
from excesses of the amplifier is a
fuse -preferably a fast -blow instrument fuse of the correct value inserted
in series with the speaker. But what is
the correct value? The individual drivers in a multi -way speaker system are
not likely to have the same powerhandling capacity. Nor should they. A
few speaker manufacturers are now
fusing some of the drivers in their systems individually, which is a great
help. But in all frankness should mention that hear frequent complaints
about blown fuses from people who
religiously follow manufacturer's fusing recommendations. Probably the
manufacturers, with worst -case situations uppermost in their minds, have
tended to be a little conservative. Still,
their advice is the best you can get for
your particular speakers.
I
I
For over a year have used 1 /ramp
fuses in my speaker lines and have
never (fortunately) lost a speaker. do
lose fuses however- sometimes as
many as three sets a month, although
have never blown a fuse on music
signals except on one occasion when
was asking for it. This is not, emphasize, a recommendation, and if
you blow out a speaker following my
practice you can't sue. But if you have
no idea on how to go about fusing
your speaker, this may be a good way
to start. Pay no attention to the nominal impedance of your speaker system, because it is in most cases "nomI
1
I
I
I
I
NEW
final," having little or nothing to do
with the impedance over most of its
frequency range.
There are on the market a few electronic speaker- protection devices that
work very well, if you can accept the
way in which they work. Usually
they're connected in parallel with the
power amplifier, so that they can
sense the amplifier output and limit
the amplifier input when a certain level
is exceeded. Their thresholds are adjustable, with very approximate calibrations provided. But what they do, in
fact, is convert your 100 -watt amplifier
into a 50 -watt amplifier, or a 10- or
1 -watt amplifier. This is because they
act so fast -faster than a fuse, which
will usually pass high -level signals of a
brief, transient nature. (The comparative slowness of fuses is a controversial issue when speaker safety is considered, but it definitely makes more
sense musically.)
More sophisticated devices are also
available. Several years ago SAE
began equipping some speakers with
active, transistorized "black boxes"
that electronically disconnected the
amplifier when hostile signals appeared. (This made sense because the
tweeters in these systems were electrostatics and had to be plugged into a
wall socket anyway.)
An elaborate protective mechanism
operating at the amplifier is the
"Dynaguard" circuit built into the
Dynaco Stereo 400 power amp. It is
adjustable to limit the steady -state
output of the amplifier from anything
from 20 to 200 watts per channel in five
steps. But its attack time is slow
enough to permit short, "safe" signal
peaks to get through. Perhaps more
important, its action, which affects
only the signal peaks, does not lop off
the tops and bottoms of waveforms
but merely rounds them, curtailing the
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generation of high- frequency distortion products (see Fig. 3). The circuit,
by the way, is rarely obvious to the ear
in operation.
Finally, relays that disconnect the
speakers in the presence of dc or
/I\\mo,
.,m ,r4
Fig. 3. Lower waveform shows effect
of Dynaguard action on sine wave
and lack of high-order harmonics.
strong subsonic signals are being incorporated in some amplifiers now.
Basically they function to prevent
"thumps" and other noises from the
speakers when the equipment is
turned on, but they will also serve in a
protective capacity, blocking other
hazardous signals that might be generated any time during operation.
Small Comforts. Articles
on
speaker failure always risk stirring up
a lot of anxiety that is frequently unjustified. Speaker systems are rugged
devices, and have to be. It is understood that they'll be used hard by anyone enthusiastic about music listening, and thus they're generally designed to hold together under any
drive conditions capable of producing
an undistorted, listenable output. If in
spite of this they begin failing chronically, then manufacturers have to
begin considering every possibility,
since consumers are frequently not
competent to diagnose what went
wrong, and sometimes their complaint reports are not honest for fear of
falling outside warranty terms. This is
why the list of potential hazards has
grown so long.
This discussion concentrates on the
relatively obscure hazards -the ones
that can't readily be heard or otherwise detected, and which therefore
can't be prevented with a little bit of
common sense. It's possible, even
likely, that not one in a thousand of
you will ever encounter a single one of
them. But if someone, somewhere is
helped by the above to discover a
problem in time, or tipped off as to the
cause of a mishap that has already occurred, then perhaps the telling of this
grisly tale is worthwhile.
POPULAR ELECTRONICS
nears
HIGHLIGHTS
Computer Pen
A new type of data input device that utilizes a special
ballpoint pen and recognition circuitry that immediately
translates hand -printed data into computer language
has been announced by the Stanford Research Institute. The Alphabec-70 system, developed at SRI, is
being introduced by Xebec Systems, a California company in computer peripheral equipment. Using the
Alphabec -70, it will be possible to instantaneously enter
hand -printed data into a processing system. In remote
locations, the data can be recorded for later transmission to the data processing center.... The first
Alphabec -70 system will have a 16- character capability
(10 digits and six control characters). A company
spokesman estimates that the system will replace many
of the 700,000 or so keyboard entry devices now in use.
The pen system eliminates keyboard -based procedures
in data entry-and with them, document re- transcription, a source of human error, delay, and expense. It is
expected to expedite field data collection in such applications as utility meter reading and sales order entry by
routemen. The system is also applicable to banking,
telephone-call logging, inventory control, and industrial
data collection.
Purchase Only 53% of TV Receiver Cost
According to a study released by MIT, the purchase
price of a color TV receiver accounts for only 53 percent
of the total amount spent on the receiver during its
useful life. Servicing accounts for 35 percent, and electrical power required for the receiver's operation claims
12 percent over the estimated 10 -year lifetime of the
receiver. "This means that the owner of a $400 color TV
[receiver] can expect to spend another $400 during its
usable life," according to the study. These figures do
not take into consideration future inflation; so, the total
cost of ownership could go progressively higher. .. .The
purpose of the study was to "examine alternatives for
increasing appliance service productivity in the context
of what the consumer pays for a product during its usable life." The study notes a substantial increase in product reliability as evidenced by a 50- percent decline in
the need for color receiver servicing during the last
eight years. However, service costs have increased so
greatly as to offset what would have been a sharply
reduced life -cycle cost.
UA Releases 10-in. 78 -rpm Disc
In keeping with the present popularity of "nostalgia,"
United Artists has released a 78 -rpm disc containing two
selections from its Golden Age of the Hollywood Musical
album. "We're in the Money" and "Lullaby of Broadway"
(both from Busby Berkeley film musicals of the 1930's)
were pressed on a 10-in. mold and fitted with record
labels that mirror the typographic and design style of the
period. This necessitated the retooling of UA's pressing
plant since 10 -in., 78 -rpm discs had not been pressed
there in more than a decade and there was only one
10 -in. die to be found in all of Los Angeles. ...The
reported vinyl shortage did not hamper progress on the
project because 78 -rpm discs are composed mainly of
`shellac and filler materials.
Good time
capfuls.
Saving fleeting moments requires a quality tape
recorder. But, just as a camera can be no better
than its lens, tapes can be no better than the microphone. Whether it costs $200, $500 -even $1,000
a tape recorder can be significantly improved by
the addition of a Shure unidirectional microphone
mike that can be "aimed" so that only the target sounds will be recorded. Microphone misers
who ignore this will never hear the true sound of
recorded music lessons, parties, classes, speech
-
-a
therapy, sound movies
and rehearsals. With
Shure microphones,
creating tomorrow's treasures is today's pleasure.
Shure Brothers Inc.
222 Hartrey Ave.,
Evanston, Ill. 60204
In
Canada: A. C. Simmonds
Limited
& Sons
SHURE
Manufacturers of high fidelity components, microphones, sound systems and related circuiry.
CIRCLE NO. 46 ON READERS SERVICE CARD
NOVEMBER 1974
27
Whya Sylvania home training program may be
your best investment
for a rewarding
career in electronics
28
POPULAR ELECTRONICS
LEADER IN ELECTRONICS
TRAINING
Over the years, Sylvania Resident
Schools have trained thousands of
men and women for key positions in
the electronics field. Now, through
Sylvania Home Training, you can
receive the same high -quality career
training at home. In your spare time.
While you hold your present job.
Remember, this training is designed
with one purpose in mind
to give
you the background you need to land
the electronics job you really want!
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Sylvania, is the proven step -by -step
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you learn the basics of electronics
quickly and easily.
3
CASSETTE SYSTEM
This innovative learning -by- hearing
approach is a special option that adds
an extra dimension toAUTOTEXT. It's
almost like having an instructor in
your own home. As you play the
cassette tapes, you'll have an instructor guiding you through your
AUTOTEXT lessons. Explaining the
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schematics with you, reinforcing the
basic electricity and electronics study
materials with you. Everything you
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towards a highly regarded position as
an electronics technician
all in an
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For those already working in electronics or with previous training,
Sylvania offers advanced courses.
You can start on a hig her level without
wasting time on work you already
know.
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construct an oscilloscope which
yours to keep and use on the job.
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To give practical application to your
studies, a variety of valuable kits are
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In the Master TV /Radio Servicing Program,
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NOVEMBER 1974
CIRCLE NO. 17 ON READERS SERVICE CARD
31
Popular Electronics
NOVEMBER 1974
-VER since we
published coostruc
riot plans for the world's first hobbyist experimenter's laser in December of 1969, POPULAF ELECTRONICS has kept readers abreasi
of .laserdevelopments.Forexample.
in January 1970, we gave details
on now to use the laser for making-
three -dimensional
holocrams.
Then, in May 1970. we publishes
plans for assembling a rase- voice
communicator (which, incidentally
was featured for several weeks in
the Smithsonian Institution)
Now. we have another break
through -plans for building the
world's first experimenter's laser
video (TV) system for a moderate
S150. (The TV camera and receiver
are extra items.)
.
THE
POPULAR
ELECTRONICS
laser TV system gives you an
advance look at a communication
system of the future. There are two
key devices in the system. One is
the composite laser tube video
modulator "transmitter" thatworks
in conjunction with a low -cost TV
camera. The other is the
detector,'r-f modulator "receiver"
that feeds an ordinary TV receiver.
(See box on Class -1 requirements.)
32
The helium -neon laser tube used
employs the latest
in the System
channel 3 or channel 4,
whichever is not in use in your
TV
aluminum cathode design. The
tube is used in conjunction with
solid -state rrodulation and detection circuits.
With the Laser TV system, you
can expect a range up to 50 ft without special optics. For extended
range, ycu can use a telescope
and /or a converging lens. More
about range later in the article.
area.
The output of the r -f modulator is
an amplitude -modulated (AM)
signal that is adjustable from 0 to 5
mV rms. This signal can be fed into
an ordinary TV receiver through its
vhf antenna terminals by means of
300 -ohm twin -lead cable.
Overall System. The block dia-
shown schematically in =ig. 2, T1.
C5 -C8, and D9 -D14 are ar-anged in
gram of the overall laser TV system
is shown in Fig. 1. The videc (or
audio, not both simultaneously)
output signalfrom the TV camera is
typically on the order of 1 volt
peak -to- peak. This signal is fed to
the laser modulator, which is designed to provide a gain of 2
mA /volt Hen,e, the 1 -volt p -p v deo
output signal from the camera,
after passing through the modulator, is converted to a 2 -mA p -p
signal teat current- drives the laser
tube.
The gain of the laser tube is
about 0-1 mW /mA, while the laser
detector has a gain of 1.25 mA /mW.
The r -f oscillator in the detector is
tunable over a 60- to 72 -MHz range
to permit the system to operate on
Laser/Modulator Circuit. In the
laser /modulator power supply,
voltage doubler conf guration
that serves as the main high a
voltage supply. This supply delivers about 1700 volts to the laser
tube. Diodes Dl -D8 and capacitors
C1 -C4 form two more voltage doublers that are "stacked" on top of
the main high -voltage supply for
ionizing the gas in the laser tube.
As soon as ionization is complete,
current starts to flow through the
laser tube. However, the values of
C1 -C4 are too low to su3port the
5 -mA tube current. So, the starting
voltage collapses and only the
main sustaining voltage remains.
Transformer T2 and its associated rectifiers (D15 -018) and
filter capacitors (C9 -C14) make up
POPULAF ELECTRONICS
ANOTHER
EXCLUSIVE
BUILD A
Laser
TV
Sgstem
BY GIANCARLO PUNIS
AND JOSEPH O'DONNELL
he low-vo tage supply that de ivers the - 20- anc 20 -volt lines for
he low -voltage portions of the
modulator.
High- impedance amplifier Q1
preamplities low-level microphcne
signals of about 0.1 volt p -p to the
I-volt p -p level required to drive Q2
-o obtain tie full 15- percent mod Jlation. (See Fig. 3 fcr the mod -
ilator schematic diagram.) The
sigh -level
J2 and the
.ac- couplet
Now you can
transmit and
receive black and white
TV pictures over
a substantial
distance with a
license free
laser beam
video link
-volt p -p video input at
collector of Q1 are both
I
to the base of Q2 aid,
-herefore, to each other. Hen :e,
when usi-rj either of the J1 (aucio)
3r J2 ( video) inputs it will be
iecessary to d sconnect the inised input. This is important to
3revent in-erference between -he
:wo signals as well as to prevent
oading C1's collector.
Transistors Q2 -Q4 each prov de
some gain at the lower =requenc es
and one stage eaci of high `requency boost, starting at about
250 kHz and ending at about 1 M-fz.
The boost characteristics are
achieved I:y the RC networks used
as emitter oads for the transistc rs.
n addition, there are -wo broadly
-uned traps consisting of
C24 /L1 /R1E and C25/L21R22 cen-ered at 160 kHz and 330 kHz.
i
response of the
The frequen,
Fig. 4A.
laser tube only is sl-own
The strong peak at 170 kHz would
cause severe cvershoots and rinai-rg on the fas- edces of TV sync
pulses or any sharp white -to -black
transitions. In addiion, U-e --3 -d3
bandwidth is oily 250 kHz wide,
with corresponding y poor picture
resolution. So, :o smooth out the
f-equency response and t3 extent
i_ beyond 500 kHz, the modulator
combines boost circuitry and traps
to yield the compensating response shown in Fig. 4B. Combiriig the A and B response curves,
tie
overall laser tube /modulator
system has the frequency response characteristic s-town i-t
Fig. 4C, which i ;adequate for most
applications.
The frequency- compensated
signal is coupled to 05, which acts
as a current so,.rce for bosh the d.
tias (trimmed tt 5 riaA by R33) and
tie ac signal cm -rents for the lases
Labe. Except for a s-nall amount cf
current through R27 and R28, the
current sources by Q5 also flows
tirough Q6 and Q7, oallast resistor
F26, and the lasertLbe. Each rate]
at 300 volts, OE and Q7 are cascaded to act as one transistor wits
a 600 -volt break -down rat ng.
33
LASER
PHOTO
-
AMPLIFIER
DETECTOR
BEAM
LOCAL
OSC
..{
TV
RECEIVER
R F
)
ANT, TERM.
Fig.
1. Block shows
the basic arrangement of
the laser video link.
Detector Circuit. Phototransistor
al
in Fig. 5 is connected as a photodiode, providing a 40 -1A p -p signal,
depending on the intensity of the laser
beam. This results in a 200 -mV video
signal at the base of Q2.
Transistor Q3 is a Hartley oscillator
stage, whose operating frequency is
determined by L1 (printed on the circuit board as part of the conductor
pattern), C7, and C8. Capacitor C7 is
adjustable to permit the circuit to operate on either the TV channel 3 or
channel 4 frequency.
TO
LASER
CATHODE
C3
N
C2
,^
1406
C4
07N
14
DII
ND6
H14
DIO
09
629
640
R30
C6
DI2
C7
+
CB
p+
D13
R3I
3
R32
014
H
DID
20V
The vhf carrier is ac- coupled to
mixer diode Dl through C6, resulting
in a video- modulated vhf signal of
about 5 mV rms with r -f level control
set for maximum output. The r -f signal
goes directly to the vhf antenna input
terminals through 300 -ohm twin -lead
antenna cable. Note, however, that
when the output of the detector circuit
is connected to the TV receiver's antenna terminals, the regular TV antenna cable must be removed.
Zener diode D2 provides a 3.6 -volt
dc bias supply for Q2 and serves as the
dc supply regulator for the Q3 oscillator circuit.
conductor power cord, held in place
with a plastic strain relief. (Or line the
hole with a rubber grommet, pass the
line cord through, and tie a knot in the
Assembling the System. Except
for the laser tube, jacks Ji and J2,
laser.
transformer Tl and power switch Si,
all components shown in Figs. 2 and 3
mount on a single printed circuit
board. The actual -size etching and
drilling guide and components
placement diagram for the laser/
modulator system are shown in Fig. 6.
To permit the etching and drilling
guide to be reproduced without reduction, it is shown in two parts. The
left edge of the lower portion butts
against the right edge of the upper
portion, with the ground bus (heavy
black areas) aligned.
When wiring the circuit board according to the diagram in Fig. 6, take
care to properly orient the components. Pay particular attention to electrolytic capacitor polarities, transistor
basing, and T2's lead routing. Bear in
mind that T2 and the laser tube mount
on the foil side of the board. Also, all
,
resistors (except R26 and R29 -R32)
and L1 and L2 mount on -end. The rest
of the components mount on the
board in the conventional manner.
Note that only C5 -C8 are axial -lead
capacitors, designed to mount flat on
the board, while all other electrolytic
capacitors are upright types.
Potentially lethal voltages are developed in the laser circuit. Consequently, it is imperative that the entire
assembly be mounted inside a rugged
preferably metal
enclosure. Use
only nylon screws when mounting
anything inside the enclosure to prevent access to any high -voltage points
in the circuit once the system is assembled. Select an enclosure that is
large enough to accommodate the
laser tube, pc board assembly, and
transformer Tl. Mount closed-circuit
miniature phone jackJl, BNCjackJ2,
and power switch S1 on the rear wall
of the enclosure. In another hole on
20V
CI-C4
001pF 2KV
R29-R32.IMEO.
C5-C8.4.70F 450V
DI
-018.164007
C9 C14IOOpF,
25V
Fig. 2. Half of high voltage
supply "drops out" when
laser starts. Lou'-voltage
supply is more conventional.
-
this wall should be the three34
cord.)
The exit hole for the laser beam
must be drilled through the
enclosure's front wall, directly in line
with the beam's travel. Use a /4 -in.
(6.35 -mm) diameter drill bit. If possible, mount a tubular flange with a ferrous outer ring as a bezel over the
hole. The ferrous ring is a convenience feature that supports the various
lenses that come mounted in circular
magnets in the event you decide to
perform other experiments using the
1
Solder push -on connectors to one
end of a red and a black 3 -in. (7.72 -cm)
or less pieces of 5 -kV test -lead cable.
Shrink tubing over the connections.
Then solder the free end of the red
cable to point A and the black cable to
point C on the foil side of the pc board.
Drill /8 -in. (3.27 -mm) holes through
the donuts marked X on the pc board.
Mount a tube mounting clamp at each
hole location. Orient the laser tube so
that its pin -connector end is toward T2
and the anode pin on the narrow neck
points toward the red cable. Set the
tube down in the clamps and anchor it
in place with rubber hold downs. Caution: Do not mount or handle the laser
tube by its narrow necks.
Slip the red cable connector onto
the anode pin of the laser tube. Then
locate the cathode pin on the opposite
side of the tube from the anode pin,
and slip the black cable's connector
1
onto it.
Solder 10-in. (25.4 -cm) long pieces
of hookup wire, preferably color
coded for easy identification, to the
remaining holes in the pc board. Slip
-in. (2.54 -cm) long pieces of heat shrinkable tubing over the wires connected to the Ti secondary points.
Then mount the board in the enclosure with nylon screws and insulated
1
spacers.
Mount Tl on the floor of the enclosure. Then locate the leads with the
shrinkable tubing on them. Route
these leads along the component side
of the board, and connect and solder
them to Ti's secondary winding,
trimming as necessary. Shrink the tubing tightly over the connections.
Complete the wiring, referring to Figs.
2, 3, and 6.
Assembling the detector is a very
simple, straightforward process. Except for phototransistor Q1 (Fig. 5),
output connector, and power switch,
POPULAR ELECTRONICS
+20V
R4
RI
220K
6.8K
CI5
CIS
ipF
IpF
R9
RB
39K
+
I6K
CIT
R12
R14
39K
12K
02
R20
6.8K
RIB
CIS
IyF
IpF
39K
+
03
2 ,44123
JI
AUDIO
R25
3.9K
R24
CI9
.IBpF
56K
04
05
2 ,44123
2 ,43908
LI
L2
IOmH
IOmH
C25I25PF
C24;IOOPF
833
5mA
IOK
ADJ.
R8
3.3K
RII
R13
8.2K 31K
3.3K
3
R18
3.3K
RI7
6.8K
R2I
RIB
IK
2.2K
R22
8.2K
R23
56K
20V
TO LASER ANODE
06
MPSU-60
-0----AAAM
R26
33K
J2
VIDEO
R27
180K
Q7
MPSU -60
R28
LASER /MODULATOR PARTS LIST
R26- 33,000-ohm, 2 -watt resistor
Cl -C4- 0.001 -p.F, 2 -kV ceramic disc
R33- 10,000 -ohm upright pc trimmer
capacitor
C5- C8- 4.7 -µF, 450 -volt axial -lead electrolytic capacitor
C9 -C14- 100 - .F, 25 -volt upright elec-
trolytic capacitor
C15- C18-1 -p.F, 50 -volt upright electrolytic capacitor
C19- 0.15 -µF disc capacitor
C20- 22-pF, 10 -volt upright
electrolytic
capacitor
C22- 200-pF, 100-volt disc capacitor
C24- 100 -pF, 100 -volt disc capacitor
C25- 25 -pF, 100 -volt disc capacitor
-A
rectifier
Dl- D18- 1000 -PIV,
C21,
C23,
1
(1N4007 or similar)
J1-Miniature
shorting -type phone jack
J2 -BNC jack
-mH choke
LI, L2
Q1-2N4124 transistor
Q2-Q4-2N4I23 transistor
Q5- 2N3906 transistor
Q6, Q7- MPSU -60 transistor (Motorola)
R1- 220,000 -ohm
R2-82,000 -ohm
R3- 10,000-ohm
R4, R17, R20-6800 -ohm
R5-390 -ohm
R6, R12, R18- 39,000 -ohm
R7, R11, R22-8200-ohm
R8, R13, R16- 3300-ohm
All resistors
R9- 15,000-ohm
RIO, R15, R21 -1000-ohm 1/2-watt, 10%
R I4- 12,000 -ohm
-l0
R19-2200-ohm
R23, R24- 56,000 -ohm
R25 -3900 -ohm
R27, R28- 180,000 -ohm
R29- R32 -1- megohm
Fig.
potentiometer
-Spst
switch
640-volt, 25 -mA power transformer
T2 -Dual 15 -volt, 25 -mA power transformer
S
I
NOVEMBER 1974
CAUTION
Tl
Misc. -Metal enclosure; printed circuit
board; laser tube No. PE719; mounting
clamps for laser tube mounting; 5 -kV
test -lead cable; three -conductor line
cord; pin connectors (2) for anode and
cathode cables; heat-shrinkable tubing;
rubber grommet or plastic cable
clamp /strain relief; nylon mounting
hardware and insulated spacers;
1000 -ohm, 1 -watt resistor (for transmitter checkout); hookup wire; solder;
etc.
Note: The following items are available
from Metrologic Instruments, Inc., 143
Harding Ave., Bellmawr, NJ 08030:
No. PE719 laser tube ($96); No. PE640
640-volt power transformer ($7); No.
PEIOI etched and drilled transmitter pc
board ($6); No. PE201 etched and drilled detector/ modulator pc board ($3);
No. PE669 complete kit of transmitter
parts, including laser tube, pc board,
transformers, metal housing, etc.
($124.50); No. PE30I complete kit of
detector/ modulator parts, including
housing ($25); No. PE500 complete kits
of transmitter and detector /modulator
parts (not including TV camera) ($148).
All prices postpaid. Canadian readers
can order from Merlan Scientific, Ltd.,
825 Lake Shore Rd., Port Credit, Ontario, Canada.
3. Frequency response of'o/deo amplifier is "tailored" to improve
laser tube's response. Resulting video modulates laser beam.
everything mounts on a small pc
board. The actual -size etching and
drilling guide and components
placement diagram for the detector
are shown in Fig. 7. Note that coil 1..1 is
part of the printed wiring.
180K
The on -board components mount in
the conventional manner. Jus: be sure
to properly polarize the electrolytic
capacitors and transistors. Transistor
Q1 mounts in a hole on one wall of the
metal enclosure, its lens "looking" to
Never look into the laser
beam proper or directly into
its reflection.
+Joao
75kHz
OdB
Oda= .ImW /mA
-10dB-18dB-
(A) LASER TUBE
+18d8-
r
+10dBOde
/
0dB2mA/V
-10dB-
(B) MODULATOR
OdB-
0da..ImV /V
I
50
(C) OVERALL
I
p
I
170kHZ
250kHZ
500 kHz
Fig. 4. Response curves of
laser tube (A) and modulator
(B) combine to provide flat
overall system, response (C).
the outside world. The phototransistor
can be held in place with a bead of
clear epoxy or plastic glue.
Install the battery on the floor of the
enclosure, under the pc board assembly, in a battery clip. And power switch
35
CI
10pF
yT
-21_
C2
005pF
R3
OK
01
MRD3050
02
294124
R2
22K
C5
50pF
+
R6
100K
RIO
81
9V
82011
D2
3.6V
,t,
C8
5pF
LI
(SEE
TEXT)
+
C3
C9I 66pF
10pF
i
R4
10K
C7
5 -30FF
o
R9
22K
03
2N3692
L2
+
C4
50pF
RI
10K
again, remove the temporary resistor
from Q5's collector circuit and reconnect Q6. Connect the anode lead to
the tube and a 0 -10 -mA meter in series
with the tube's cathode pin and the
cathode (black) lead. Make certain
that the mil liammeter and its leads are
well separated from ground and the
low- voltage circuits.
Plug in the line cord and turn on the
power. After a short lag, the gas in the
laser tube should ionize and glow
R5
27011
R7
25011.
620pM
C13
CIO
R8
33011
pF
C11
.005pF1
10pF
C12
+
.005pF
TTT
30011 LINE
DETECTOR /R -F MODULATOR PARTS LIST
BI-9-volt battery
CI, C3, CI 1-10-AF, 10 -volt electrolytic
capacitor
C2, C10, C12, C13- 0.005 -MF disc
capacitor
C4, C5-50-AF, 10 -volt electrolytic
capacitor
C6- 7.5 -pF silver-mica capacitor
C7-5 -30-pF miniature ceramic trimmer
capacitor
C8 -5 -pF silver-mica capacitor
C9 -68 -pF silver-mica capacitor
DI -1N295 diode
D2 -3.6 -volt zener diode (1N747 or similar)
LI
-f coil (etched on pc board)
L2-620 -0H choke
QI -MRD-3050 phototransistor (Motorola)
-R
Q2- 2N4I24 transistor
Q3- 2N3692 transistor
Rl, R3, R4- 10,000 -ohm
R2, R9- 22,000 -ohm
R5-270 -ohm
R6- 100,000 -ohm
All resistors
%rwatt, 10%
R8-330 -ohm
R10-820-ohm
R7 -250 -ohm vertical pc -type trimmer
potentiometer
-Spst switch (optional)
Misc.- Chassis box; printed- circuit
S1
board; battery clip: output cable connector (optional); 300-ohm twin -lead
cable; hookup wire; spacers (2); hardware; etc.
(Note: For kit information, see Laser/
Modulator Parts List.)
Fig. 5. Photodetector modulates oscillator on channel 3 or 4 to generate signal
that goes via 300 -ohnt line to television ree eiver's antenna terminals.
Si and the output cable connector
mount on the rear wall of the enclosure.
System Checkout. Before applying
any power to the laser /modulator,
double check all components for
proper installation. Check particularly
for cold solder joints and solder
bridges. If everything checks out okay,
disconnect the primary of Ti, Q6, and
the laser tube from the circuit.
Temporarily connect a 1000 -ohm,
1/2-watt resistor between Q5's collector and the -20-volt bus. Turn on the
power. Now, using a high- impedance
multimeter (a 20,000- ohms /volt VOM
will do), check to verify that +20 and
-20 volts dc is available from the
power supply. Because of the temporary collector load, Q5's collector will
be at about -15 volts. Adjust R33 for a
reading of exactly 5 volts across the
temporarily installed 1000 -ohm resis36
tor. Alternatively, insert a milliammeter in series with the resistor and adjust R33 for a reading of exactly 5 mA.
Turn off the power and disconnect the
line cord from the ac receptacle.
Wire T1 into the circuit. Before ap-
plying power, remember that potentially lethal voltages are present at the
negative end of C5 and the cathode
(black) lead. Keep the latter well away
from ground and the low- voltage circuits. The starting voltage at the top of
C3 can be checked, but the meter has
a loading effect on the circuit. So, do
not expect to read more than about 3.5
kV when making measurements on
the 5-kV range with a 20,000 -ohms/
volt meter. Turn off the power, and remove the plug from the ac receptacle.
After power is removed, do not touch
any part of the circuit for about
five minutes until the high -voltage
charges on the capacitors dissipate.
When the circuit is safe to handle
CLASS -1 TV DEVICES
There has recently been a proliferation of
electronic games designed to be used with
a conventional TV receiver. These socalled "Class -1" devices apply a modulated low -level r-f carrier signal directly
to the receiver's antenna terminals. Because they might produce interference, the
FCC has placed restrictions on the manufacture, sale, and use of Class -1 devices,
of which the laser detector /r-f modulator
in this article is one.
Class-1 TV device requirements are:
1. They must operate on a channel allocated for vhf or uhf broadcast TV.
2. They must transmit the r-f signal to
the TV receiver by wire or cable.
3. The r -f output level must be less than
6 mV rms into a 300-ohm output.
4. A transfer switch with 60 dB of isolation must be used for switching the antenna terminals between the TV antenna
and the Class-1 device.
5. The peak envelope power of any
spurious emission at frequencies 3 MHz
or more from either edge of the standard
TV channel being used must be 30 dB or
more below the peak envelope power of
the in -band signal.
6. Radiated EMI from the device must
be less than 15 MV /meter at 2.6 ft. (0.79 m)
from the detector modulator.
7. The device must be formally type approved by the FCC. In the case of a kitform Class -1 device, only the manufacturer of the kit is required to obtain type
approval.
The above list of regulations applies
only to the detector/r -f modulator portion
of the laser TV system. No specific restrictions are placed on the laser transmitter. With regard to the isolating switch, the
laser TV system has none, but removing
the TV receiver's antenna will satisfy the
requirement. (Bear in mind that it is illegal
to have the detector's output cable and the
TV antenna hooked up to the TV receiver
at the same time.)
The detector /r-f modulator has been
type approved by the FCC. However, it is
strongly urged that if you build your own
instead of buying the kit from Metrologic,
you faithfully follow the pc layout and assembly instructions presented in this article.
POPULAR ELECTRONICS
06
E
-
07
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B
C
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R26-
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TI PRIMARY
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T
CD
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R29-a
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015
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4
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LASER
CATHODE
+
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T
*
-CI l *
DI
Fig. 6. Actual -size
etching and drilling guide
for power supply and
modulator is shown in two
parts (center). The
component-placement guides
are shown above (top)
and below (left) their
respective etching guides.
Dá
Ce
+
NOVEMBER 1974
-* -
*DD
SEC
C7
-R31
1
'I
C6
DT*
D9
i
37
-
1,
n
°
+
\
Fig. 7. Actual-size etching
guide for detector /modulator
(bottom) features printed
r-f oscillator coil. Componentplacement guide is at left.
picture on the screen of the TV receiver, while video -modulating the
laser. Then adjust pot R7, and the TV
receiver's brightness and contrast
controls for the best picture quality.
Also, if the TV camera does not have a
wide agc light range, its lens should be
adjusted as well for best picture.
Setup and Use.
orange. (Caution: Never look into the
laser beam or directly into the reflected beam.) The milliammeter at
this time should indicate a 5-mA current flow. If necessary, touch up the
setting of R33 to obtain a 5 -mA reading. Then turn off the power and remove the line cord from the ac line.
Again, do not touch the assembly until
the high -voltage charges have bled off
the electrolytic capacitors. Then remove the milliammeter and reconnect
the black cable to the cathode pin on
the laser tube.
Reapply power to the system. Now,
exercising extreme caution, measure
the collector- emitter voltages on Q6
and Q7. Both transistors should have
approximately the same voltage drop.
An unequal drop indicates that something is wrong, meaning that you will
have to troubleshoot the circuit.
Since the detector employs only a
low- voltage battery supply, it is safer
to work on than the laser/modulator.
The emitter of Q1 should be at 0 volt
with no light entering the phototransistor through its lens. With the laser
beam impinging on the sensitive surface of Q1 the emitter will be at about
2 volts. (Note: A 20,000- ohms /volt
meter will load this down to about 1.6
volts.)
Connect the r -f output line to the
antenna terminals of a conventional
TV receiver, after first removing the TV
antenna cable. Adjust C7 for operation
on either channel 3 or channel 4,
whichever is not in use in your area.
Now, modulating the laser with a TV
camera, an oscilloscope should reveal
the composite video signal at the emitter of Q1 at a level of about 220 mV p -p.
(Almost any type of oscilloscope can
be used here.) The waveform at the
cathode of D1 will be the video modulated r -f signal operating at
about a 5 -mV p -p level. It may be
necessary to adjust R6 to obtain the
correct signal level.
If you do not have access to a scope,
set potentiometer R7 to the middle of
its range. Set the TV receiver to the
unused channel 3 or 4. Very slowly
adjust C7 for the clearest, sharpest
,
38
In setting up the
laser TV system, bear in mind that
adequate light must be on the subject
to be televised. Avoid subjects (pictures) that have very bright and very
dark contrasts close to each other.
Focus the camera carefully, and select
the best lens opening for the subject
to be televised.
When mounting the laser /modulator and receiver, use solid supports
to obviate vibrations and shifts that
might cause the laser beam to miss the
phototransistor in the detector and result in transmission drop -outs.
The uncollimated beam from the
laser has a 1- milliradian divergence
characteristic that causes the spot to
spread to about 1 meter in diameter at
1000 meters. So, if you plan on long distance transmission of the laser
beam, you must use collimation to
keep the beam as narrow as possible.
The collimator is simply a telescope
used backwards, with the laser beam
fed into the eye -piece and exiting
through the large end of the telescope. You can use either a reflecting
or a refracting telescope.
The greater the power of the telescope used, the greater the range you
can expect and the tighter the laser
beam. However, with increasing
range, optical alignment becomes a
critical factor. So use a solid mount for
the telescope.
Range can also be increased with a
light- gathering lens at the detector
end. This is comparable to using a
high -gain antenna for radio waves.
You can buy lightweight plastic Fresnel lenses measuring up to 11 in.
(27.94 cm) square at very reasonable
prices. Such lenses make excellent
light gatherers. They must be focused
on the sensitive surface of the photo transistor in the detector.
Long- distance alignment can be
simplified in several ways. Use a rigid
mounting system and some form of
vernier positioner (for fine adjustment) for aiming the laser. Perform the
alighment at night when the bright red
laser beam is easier to see. For night
setups, a bicycle safety reflector will
prove useful in following the beam to
the detector target.
POPULAR ELECTRONICS
HOW THE
NEW FTC
Hl-Fl RULES
AFFECT YOU!
BY LEONARD FELDMAN
EFFECTIVE November 4, 1974,
new rules governing the disclosure of the output power of audio amplifiers and receivers go into effect.
The new rules were promulgated by
the Federal Trade Commission after
several years of study. They follow a
long period of advertising abuse by
some segments of the electronic
home -entertainment industry.
Well- known "low-fi" productsclaiming output power capabilities of as
much as 100 watts "instantaneous
peak power (IPP)" have been measured by reputable laboratories and
have consistently produced no more
than a few watts of output power per
channel at best. Meaningless terms
such as IPP, peak power, peak music
power, and dynamic music power
they are to be used in the future at
all -will have to be given less typographical prominence in all advertis-
1.0
/
8
-OHM LOADS
I
-
C
Still Room for Ambiguities.
Will
the FTC rule end the confusion about
NOVEMBER 1974
i
/
0.2
A
-if
ing media.
'
ALL AMPL FIERS REFERENCED TO
10
20
30
40
50
POWER OUTPUT /CHANNEL (WATTS)
60
70
1. When all three amplifiers are measured the
same way, "lower spec" amplifier A turns out
to be the highest powered unit among the three.
Fig.
39
power ratings in the minds of all consumers? Unfortunately, the answer is
a resounding "No!" While the rule
goes a long way towards enforcing
honesty in audio equipment advertising, adherence to its requirements will
not, in and of itself, make everyone's
power specifications read like
everyone else's. The consumer can
still be thoroughly confused when
reading specification sheets describing competitive amplifiers and receivers. Here is why confusion can arise:
Henceforth, manufacturers will be
required to state continuous output
power delivered by their products into
a specified impedance, at a specified
harmonic distortion, and over a
specified power bandwidth. The
power specified in this manner must
be delivered by the amplifier or receiver when all its channels are driven
simultaneously. For a stereo receiver
or amplifier, this means that both
channels must be going at the same
time, while in a 4- channel setup, all
four amplifier channels must deliver
the rated power to all four loads at the
same time.
Let us consider the following sets of
competitive specifications, all of
which would comply with the "letter of
the law ":
AMPLIFIER A: 50 W /channel output
power into 8 ohms at 0.3 percent harmonic distortion from 20 Hz to 20,000
Hz.
AMPLIFIER B: 60 W /channel into 4
ohms at 0.5 percent harmonic distortion from 60 Hz to 400 Hz.
AMPLIFIER C: 65 W/channel into 4
ohms at 1.0 percent harmonic distortion from 60 Hz to 4000 Hz.
Reading these three descriptions,
the uninitiated consumer might conclude that Amplifier C has the greatest
output power capability. He would be
wrong. Nearly all solid -state amplifiers
produce their greatest output power
-if
u
z
03
i-
levels when connected to 4 -ohm
speaker loads. Connected to more
popular 8 -ohm speaker system, Amplifier C might well produce less than 50
watts.
Notice, too, that the rated distortion
of Amplifier C is 1.0 percent. How
much less power would it be able to
deliver-even into its 4 -ohm specified
loads
distortion were limited to 0.5
or 0.3 percent, as in the cases of Amplifiers B and A? For that matter, we
have no way of knowing from the figures given whether or not the distortion level will ever go down to the
0.3- percent level. Perhaps 1.0 percent
is the best Amplifier C can do even at
low output power levels.
The new FTC rule merely requires
that the amplifier be able to deliver its
specified power at a harmonic distortion that does not exceed the published figure. Doing some hypothetical calculation based on typical
measurements observed with "real"
amplifiers, Fig. 1 plots power versus
distortion curves for our three fictitious amplifiers. The parameters were
changed so that each amplifier was
operated into 8 -ohm loads, and all
three were permitted to reach a distortion level of 1.0 percent, so that the
comparison would be fair.
As you can see, the results are just
the reverse of what is implied by an
uninformed reading of the specification listings given earlier. Amplifier A
produced 68 watts under these conditions, Amplifier B produced 50 watts,
while the amplifier with the highest
"published" power rating -Amplifier
C- produced only 48 watts.
In the example, we were dealing
with only a single middle-of- the -band
audio frequency. However, the FTC
rule requires that the power bandwidth over which the rated power can
be developed at rated (or less) distortion must be specified as well. Refer-
ALL AMPLIFIERS MEASURED AT 50-WATTS/CH.,
Ó 2,\5D
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2. D
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A
100
K
FREQUENCY
- Hz
IOK
Fig. 2. Again, amplifier A proves to be much
lower in distortion than amplifiers B and C, in
spite of its more conservative published spec.
40
ring again to the "published" specifications given above, each manufacturer has complied with this requirement. The maker of Amplifier C has
honestly stated that his amplifier will
deliver 65 watts at any frequency between 400 and 3000 Hz. But most of us
know that the real test of a good amplifier is its ability to deliver maximum
power at the frequency extremes. This
is particularly important at low bass
frequencies where musical energy
demands are usually greatest. The
thundering beat of a bass drum calls
for more power than is required when
reproducing the sounds of instruments and voices in the midrange register.
Reading the specifications of Amplifier C, we have no way of knowing
how much power the product can deliver (if any) at40Hz and lowerfrequencies, or at what level of distortion. The
curves in Fig. 2 show what the distortion of each of our fictitious amplifiers
might look like even if we were to
use 50 watts /channel as a reference
power level. Again, contrary to first
impressions, Amplifier A comes up
the winner as far as distortion is concerned.
Buyer Beware -Still. So, while the
new FTC rule may alleviate some of
the worst abuses of the industry, it
does not entirely correct them. In fact,
many consumers may falsely conclude that, with the FTC in the act, all
product specification sheets are
going to read the same-that they will
be comparing apples to apples.
You can be sure that manufacturers
who have reason to "gimmick" their
specifications will still find enough
ways to obscure the facts. The component manufacturers who have always sought to tell the true performance story of their products did not
have to wait for federal legislation to
adhere to truth -in- advertising doctrines. They have been specifying continuous power over the entire audio
range, from 20 Hz to 20,000 Hz, at low
distortion levels and with all impedances defined since long before the
FTC ever heard about watts, decibels,
and THD.
The Institute of High Fidelity (IHF)
hopes, before long, to publish more
complete measurement standards for
amplifiers. If adhered to, the new
standards would help to eliminate the
many ambiguities that still remain
prevalent, even in the face of the new
FTC requirements.
POPULAR ELECTRONICS
ov1V
c915
VAC»
MANUFACTURERS of TV receivers unveiled many innovations
in their 1975 models. For example,
major moves have been made toward
providing brighter, sharper color pictures; tuning is getting closer to the
one -button concept; power -supply
designs indicate a trend toward compensation for anticipated voltage fluctuations caused by power shortages;
and serviceability has been improved
with modular designs and other
niceties. Here are details on what each
major color TV manufacturer is offering in their 1975 all- solid -state chassis
lines.
Admiral.
The latest in Admiral's line
of color TV receivers is the Touch
Tuning M25 chassis. Its main feature
is a tuning system programmed with
toothed cards. Six printed- circuit
cards are used to program uhf channel number readouts. A seventh is for
programming the remote control
channel selector to go to the next
higher active channel, bypassing all
inactive channels. The cards are prepared for individual viewing situations
with the aid of longnose pliers.
Once the cards are prepared, they
are inserted into connectors in the
tuner. This permits the viewer to select
a channel from the keyboard or the
remote control transmitter. The channel appears on the screen, and a separate readout indicator displays the
channel number.
In the companion M30 chassis, a
special transformer provides voltage
regulation. The transformer is wound
in such a way that its secondary pro NOVEMBER 1974
BY ART MARGOLIS
duces fixed -amplitude square waves,
with the transformer operated at saturation. The transformer is tuned to
resonate at the line frequency with the
aid of a capacitor.
When the input voltage is nominally
117 volts ac, the clipped output voltage is a fixed -amplitude square wave.
Should the line voltage vary (within
±10 percent of nominal), any change
produces an inverse change in the
clipping action. The peak -to -peak
square wave applied to the rectifiers
then remains at about the same amplitude.
While the Admiral chassis does not
tilt (it is horizontal), it does slide out for
easy servicing.
General Electric.
MB, MC, QB, and
YA are the designations given by General Electric to its 1975 chassis. The
stress is on reliability, quality, and performance. For 1975, GE is introducing
the third generation of its Quadline
color picture tube. In -line gun arrangements are featured in the
Porta -Color 13- and 15 -in. picture
tubes. The tubes have short necks and
90° deflection angles. The necks are
up to 2 in. shorter than comparable
tubes with triangular gun arrangements, which eliminates the bump on
the rear of the cabinet. Also, the in -line
arrangement reduces from 12 to 8 the
number of convergence adjustments
that must be made.
In addition to manual and preset
color, tint, and brightness controls,
there is a Custom Picture Control.
Coupled to the contrast, color, and
brightness circuits, it adjusts all three
parameters simultaneously to maintain a balanced ratio.
A One-Touch Color system incorporates tint lock, avc, and the preset
color tint and brightness. The tint lock
widens the demodulation angle by
cross-coupling B -Y and G -Y at the
output of the chroma demodulator IC.
The seven models in the YA series
have chassis that accommodate about
90 percent of all the electrical components. Off -the -module components
are overrated to increase reliability.
More than 95 percent of component
failures are claimed to be repairable
by module replacement, and all IC's
plug in for easier servicing. To further
endear itself to the serviceman, GE
has a lot of the service information
pasted on the inside of the cabi net and
printed on the circuit boards. This includes layouts, catalog part numbers,
detailed adjustment instructions, and
even the schematic.
In the larger chassis (like the MC
series), a high -voltage quadrupler that
develops 30 kV is used instead of the
usual tripler. Regulation of the 30 kV is
achieved with a three -winding saturable reactor circuit.
Heath Company. The latest kit marvel from Heath is its Model GR -2000
digital color TV receiver. The tuner
uses a varactor diode that eliminates
41
moving parts. An up /down counter
digital programming board has provisions for presetting up to 16 channels
in the vhf and /or uhf bands in any sequence, even repeating channels if
desired. The tuning, activated by a
front -panel control or a button on the
optional remote control transmitter,
sweeps up or down through the 16
preset channels.
The number of the channel selected
can be placed anywhere on the screen
for a preset time of up to 90 seconds,
or it can be set permanently on. The
brightness of the display is adjustable.
And the numerals can be instantly recalled at any time by tapping the
volume -down button on either the receiver or the remote control transmitter. The numeral readout is digitally
generated by
l'hilco ;Wade/ ('1922FIf1V
a
special character
generator IC on one of the receiver's
modular boards.
As icing on the readout cake, Heath
offers an optional 12/24 -hour digital
clock accessory that fits into the receiver. It generates the time in an
hours/minutes /seconds format. The
time is displayed on the screen, simultaneously with the channel number.
The receiver's plug -in IC amplifier /fixed -tuned LC filter -f strip eliminates the need for periodic sweep
alignment. Serviceability is aided by
such niceties as modular circuit
boards, built-in dot generator, slide out service drawer, and an illustrated
troubleshooting guide in one of the
manuals. A test meter also comes as a
basic part of the receiver kit.
i
Sony Model KV-1920
THE NEW
Company
Magnavox. The latest color
TV re-
ceiving system from Magnavox is
called the STAR (for Silent Tuning
At Random), which refers to its
varactor -diode tuner. The viewer can
call up any vhf or uhf channel by
punching buttons on a compact remote control transmitter. The receiver
instantly and silently tunes to the
selected channel. The tuning system
is not sequential; it goes directly to the
selected channel without having to
clunk through all the in- between
channels. A special circuit in the receiver displays the channel's number
in bright numerals on the upper left of
the screen for about 3 seconds.
Depressing the M (for mute) button
on the remote control transmitter
turns off the sound for 1 minute without disturbing the picture.
The latest in negative guard band
color picture tubes is used in the 13through 19 -in. STAR chassis. These
tubes have a black matrix surrounding
color stripes (not dots). The electron
guns are arranged in -line (rather than
in the usual triad configuration), reducing the number of convergence
adjustments that must be made. Finally, the picture tubes' necks are
shorter than usual. (The 25-in negative
guard band picture tube requires a
wide deflection angle that precludes
an in -line gun arrangement.)
The power supply employs a new
voltage -regulating transformer in a
special circuit whose output maintains relatively constant voltage during minor changes (a few percent) in
1915 ALL -SOLID -STATE TV RECEIVER CHASSIS
Tuner
Chassis
I
-F Strip
Channel
Muting
Indicator
Admiral
M25
Varactor
Transistor
MC
Varactor
IC
Selector dial
Yes
General
Electric
Digital (on
No
control panel)
Heath
Varactor
GR-2000
IC/Fixed-
On
tuned
(Time optional)
LC
Magnavox
Star
Varactor
MOSFET
Panasonic
Quatrecolor
Detent
IC
ilco
Boss
Varactor
QS -3000
Detent vhf
Ph
Quasar
IC
screen
Yes
On screen
Yes
Selector dial
No
Selector dial
No
Selector dial
Yes
Varactor uhf
RCA
Digital (on
Detent
XL-100
No
control panel)
Sony
Sylvania
Zenith
Heath Model GR.2000 with on- .screen
channel and optional time
42
Selector dial
Detent
kV series
GT-matic
II
Chroma -color
II
Varactor
Transistor
Digital
Yes
Varactor
Transistor
Selector dial
Yes
Note: All chassis are solid -state and modular and have negative guard band picture tubes, aft, audio
output jacks, automatic degaussing, and 300/75 -ohm antenna inputs. All have electronic remote
control except Zenith (see text).
POPULAR ELECTRONICS
NEGATIVE vs POSITIVE GUARD BAND
COLOR PICTURE TUBES
In a standard color picture tube, 85
percent of the screen is covered with
phosphor dots, with nothing between
Ahem but an aluminized coating that
covers the entire face of the tube. The
dots are 17 mils across, while the electron beams are 13 mils in diameter.
This means that the beams cannot
completely excite the dots. In fact, only
about half the area of each dot ever
becomes excited. The part not excited
is required as a "guard band" to pre vent degradation of color purity resulting from the beams overlapping onto
adjacent dots.
Ambient light is reflected from the
aluminized coating and tends to wash
out the picture. So, a tinted face glass
must be used to reduce glare. Tinting
works, but it also kills about half of the
light from the dots. This system is referred to as "positive guard band" because the unexcited portions of the
dots protect purity.
In the "negative guard band" sys-tem, as employed in many of the latest
color picture tubes, the dots are surrounded by an opaque black material.
The electron beams are allowed to be'come thicker than the diameter of the
;dots by increasing the sizes of the
,holes in the shadow mask. The entire
dot can now be excited, while the black
'material serves as the guard band. Tint ing is not required because ambient
light is not reflected by the black surround. Hence, a full 85 percent of the
Ilight produced by the excited dots
I comes through the picture tube's fa plate.
the line voltage. The high -impedance
MOSFET -f module gives the -f strip
improved sensitivity and reduces any
tendency to overload.
The STAR's modular design caters
to serviceability. And the vertical
chassis has 20° and 45° tilt positions.
i
i
Panasonic. Quatrecolor
is the name
of Panasonic's line. The new Quintrix
color picture tube employs a negative
guard band black matrix with an additional pre-focus lens to make the picture sharper and brighter by bunching
the electrons into a narrower beam.
The featured Q -lock one -button color
system is like the preset control systems, except that the color and tint are
adjusted on a continuous basis, while
brightness and contrast adjustments
are made via preset potentiometers
with
a
fixed control.
The electronic remote control system permits up /down channel selecNOVEMBER 1974
tion. A "vacation" switch on most
models defeats the Speed -O- Vision
instant -on feature. The vhf dipole antenna is detachable to permit it to be
moved around the room to where it
exhibits the best signal -gathering performance. This is a convenience if the
TV receiver is set into a permanent
location.
Philco. The solid -state modular color
TV receiver chassis from Philco is
called BOSS (for Best Of the Solid
States). It features a 37- to 47- percent
power saving over last year's hybrid
receiver models, tilt -out front controls, and a built in Invis -A-Tenna with
its own reception selector.
Voltage regulation and suppression
are accomplished by Picture Guard
and Surge Guard in the Philco receivers. In the event of a sudden voltage
spike, due to lightning or voltage
transients on the power line, a filter
capacitor absorbs the temporary overload.
Hands-off tuning is accomplished
by a network of automatic circuits.
The viewer engages the Philco Master
Control button and selects a channel.
When the Philcomatic COLOR Control light comes on, he pulls his hand
away and the receiver automatically
tunes itself.
Quick On replaces Instant Play to
eliminate power wastage by not having the picture tube's filaments continuously powered. The audio still
comes on immediately, while the picture follows a few seconds later.
Quasar. The "works
in a
Choosing channels on Zenith's color
TV receiver line is accomplished
with non- detented slide control
drawer"
people are featuring more serviceability, line- voltage regulation, a picture
system responsive to ambient lighting, and more simplified and reliable
modules. A special twist-lock connector is used to simplify removal of the
power supply by the serviceman. This
connector eliminates multiple wire
leads that could have been potential
trouble spots.
Quasar's Insta-Matic system employs a patented demodulator IC that
RCA XL -100 Model GT -795
a light dependent resistor. The LDR is
works in conjunction with
mounted behind a honeycomb lens
located on the front panel of the receiver where it measures the ambient
light and allows more or less current
to flow into the video -chroma circuit.
This automatically raises or lowers the
brightness, contrast, and color to suit
the light level in the viewing location.
On the remote control panel is a
Panasonic Model CT-93{
43
SYNC
TIMING
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RCA. Continuing its XL -100 color TV
Sylvania's vertical ramp and drive waveform generator
,
PART OF
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APPLIED
VOLTAGE
-
MANUAL
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CONTROL
1.
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NEW
INTEGRATED CIRCUIT
PERMITS SIMULTANEOUS
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Quasar's automatic picture
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with room lighting
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GE's MB chassis uses saturable reactor (T1704) for high -voltage regulation.
44
receiver system, RCA has shaped up
the 1975 line by installing an electronic digital display for the vhf and
uhf channel numbers. The display is
on the control panel, rather than onscreen.
There are no more tubes (except for
the latest negative guard band color
picture tube) in the RCA lineup. The
instant -on feature common in earlier
XL -100 models has been eliminated in
a move toward energy conservation.
Going all solid state and eliminating
instant-on, RCA claims an energy savings of 27.5 percent over its tube -type
receivers.
The concentration in the XL-100 line
is on the Acculine portable color TV
receivers. The deflection yoke is permanently bonded to the Acculine picture tube (which, incidentally, has an
inline electron gun arrangement) to
prevent it from shifting position.
Hence, the yoke is an integral part of
the picture tube.
Between the Acculine tube and the
bonded yoke, there are only four
dynamic convergence adjustments
instead of the usual 12 that must be
made for setting up the receiver. There
is also only one purity adjustment
-the purity magnet- instead of the
usual two. The second purity adjust-
E
PLUG
+143V
volume -step IC /LED system. Volume is
muted or varied by the differences in
brightness produced by the LED's
glow. In the receiver is a Slumber Sentry circuit. It samples the vertical and
composite sync pulses. If the receiver
is left on after the station signs off, the
Slumber Sentry detects the loss of
sync pulses. Then it automatically
shuts off the receiver following a short
delay. [Panasonic recently purchased
Quasar from Motorola -Ed]
Sony. Sony this year offers the KV
color series, featuring its Trinitron system, which uses color stripes in a
negative guard band matrix, and an
in -line gun arrangement, and the TV
transportable lifestyles line. Sony incorporates 114° wide -angle deflection
picture tubes and Econoquick instant-on features for greater viewer
pleasure and convenience. One of the
major benefits of the Trinitron system
is the elimination of costly, time consuming set -up adjustments that
conventional three -gun color systems
require.
POPULAR ELECTRONICS
The KV series features one button
control for Automatic Fine Tuning,
Color and Hue for accurate and simple
color reception adjustment. Optional
accessories for the Sony line include
rechargeable battery packs, car battery cords, sun glare filters and auto
and home antennas.
Sylvania. The new Sylvania chassis,
Quasar's
100 -percent
solid -state chassis'
modular design system
called GT -matic II, is said to add
another dimension to no- button tuning. Parroting preset adjustments, the
viewer simply turns on the power and
selects the channel. Then, the receiver
automatically sets the proper volume,
brightness, contrast, color, tint, and
other major tuning requirements. Automatic vertical and horizontal holds
and Perma Tint supplement the preset
controls. A pushbutton varactor tuner,
muting, instant -on, remote control,
and 100 -percent solid -state chassis
round out the GT -matic II's features.
The automatic vertical and horizontal holds are controlled by a six section IC that produces a synchronized horizontal and vertical scan
system. Other automatic circuits work
on reducing airplane flutter, maintaining a constant voltage, etc.
The Perma Tint circuit acts as a
monitor to maintain color at preset
levels. It attempts to reduce flesh -tone
changes. Once the hidden controls
are adjusted as desired, the Perma
Tint control can be activated, increasing the demodulation angle between
R -Y and B -Y to provide a wider
range of phase angles for determining
the actual color of the flesh tone.
The red demodulator IC gates the
Perma Tint on only when there is a
positive component of R -Y present.
This limits the effect of the increased
angle to only those colors in the flesh tone range without affecting the
yellow -green, green, cyan, and blue
colors.
Serviceability in the GT -matic II
chassis is supported by plug -in devices and modular arrangement of the
pc boards.
features an all- solid -state vertical
chassis, voltage regulation, and onebutton preset controls.
The Space Command remote control transmitter still uses a mechanical, rather than an electronic, scheme.
A tiny hammer in the transmitter
strikes a rod that then vibrates at a
specific frequency. The sound thus
produced (it's beyond human hearing)
activates the specific control channel
in the remote control receiver.
Zenith. For
1975, Zenith is introducing its Chromacolor Il receiver line. It
Z 0+25G`J
Magnavox's remote- control system
features on- screen channel
number in sewn -.segment. format.
A
FIXED
AMPLITUDE
I
0
B+TSV
TO PILOT LIGHTS
CRT
FILAMENTS
NOVEMBER 1974
Admiral's power supply system
features fixed-amplitude
outputs that minimize voltage reduction effects over a
wide range of variations.
Zenith calls its modular construction "plug -in /pull -out" Dura- Modules.
Eight modules accommodate 75 percent of the circuitry in the receiver.
Tuning in the Zenith receivers is accomplished with 14 preset channels
and a slide- switch arrangement. The
presetting need not be sequential.
In Conclusion. So it is obvious that
the consumer has many new features
to look for when buying a 1975 TV receiver. Of course, he will have to expect to pay a little more for these innovations. But, in the long run, the initial
investment may be returned to him in
the form of fewer service charges and
an increase in the life of the set. O
45
THE FCC now allows FM stations
to use a combination of Dolby
B -Type noise reduction and reduced
pre- emphasis in their signal processing. Here's why the new proposal was
accepted and how it affects the performance of your FM tuner.
For years, many responsible people
in the broadcasting field have privately or publicly suggested a reduction in pre- emphasis. This process
was introduced in the early days of
FM. It boosts the level of high frequency content by passing the
baseband signal through an RC
high -pass filter with a 75-ps time constant, a break frequency of 2.123 kHz,
and a 6 -dB /octave slope. In this way,
the S/N (signal -to- noise) ratio of the
FM channel is increased. At the receiver, de- emphasis must be introduced to balance the spectral content
of the received signal as in the original
information. The de- emphasis network is a simple low -pass RC filter,
with a -6 -dB /octave slope, a 75 -ps
time constant and 2.123 -kHz break
frequency. The time constant was
chosen at a time when there was marginal high- frequency content, by
today's standards, in recorded sound.
A low break frequency was required to
radically boost the highs to prevent
them from being lost in the high frequency noise that is characteristic
of FM.
Today, we have reached a point
where the recording media can give
much flatter frequency response.
Anyone who has compared an old and
a recent recording of a certain piece
will note a dramatic increase in high frequency content, or a more "brilliant" sound. This presents problems
to FM broadcasters, though. They are
constrained to a frequency deviation
of 75 kHz, and with increased high frequency content, they must either
lower the modulation index, or use
high- frequency limiting. Stations with
integrity will not color the sound of the
modulating signal, and thus lose some
of their potential audience to less
scrupulous, but louder competitors
who shape the spectral content of the
baseband signal to achieve higher
levels of modulation while staying
within the law.
The proposal by Dr. Dolby will redress the inequities of the situation. If
the level of pre- emphasis were reduced, using a 25 -ps time constant
and 6.36 -kHz break frequency, stations could modulate their carriers
more fully, and their signal strengths
46
duction is almost completely counterbalanced by the effects of B -type
compression. In low-to- mediumquality equipment, there is no noticeable difference, and the increase in
the highs noticed from medium -tohigh- quality equipment can be compensated for by a slight reduction of
high response of the amplifier using
the treble control(s).
NEW
DOLBYENCODED
FM
BROADCASTS
would increase an average of 4 dB.
However, the sound from the millions
of FM tuners already in use, with their
75-ps de- emphasis networks, would
be exceedingly dull. Obviously, the
FCC could not allow such incompatibility to be introduced. If FM stations
simultaneously change the time constant of their pre-emphasis networks
to 25 psand incorporate Dolby B -Type
noise reduction, an interesting situation arises.
The reduction of high- frequency
brilliance caused by pre- emphasis reFM TUNER
OUTPUT
ZIK
3900pF
75Ps
supply.
20K
The PLAY CAL controls on the noise
reduction unit should be turned to
25M$
FM CAL
Brilliance is a subjectively measured quantity, and to ascertain the effects of B -type encoding, several stations switched unannounced to the
new system. Many listeners wrote letters praising the increased quality of
the sound. Not one complaint was received.
For those with conventional receivers and no noise reduction, there will
be a reduction of high- frequency distortion, and an increase in brilliance
and program level. Listeners equipped
with 25-ps de- emphasis and Dolby BType noise reduction, as produced
now by Dolby licensees as per Dolby's
advice, will receive four benefits: improved signal to noise ratio; full program dynamic range, even at high frequencies; better reception in weak signal areas; and reduced likelihood
of SCA interference.
Some tuners and receivers are already equipped to receive the 25 -ps
Dolby encoded FM broadcasts. If a
75/25 switch is on the back of the unit
it should be set at 25 during reception
of all subsequent Dolby FM broadcasts. Otherwise, ordinary B -Type
noise reduction units can be easily
adapted to take advantage of the new
broadcast technique by installing the
FM Compensator shown in the diagram. Only one channel is illustrated;
two will be required for stereo reception. Anyone may build a compensator
for personal use or manufacture it for
resale without a license. The parts are
inexpensive and may be obtained
from any electronics supply house.
The unit does not require a power
FM
I0K
TO
FROM RECORDER"
INPUT ON NOISEREDUCTION UNIT
TAPE
RECORDER
OUTPUT
TAPE CAL
10K
FM compensator provides choice
of 75- or 25 -ps time constant.
maximum, and TAPE CAL control on the
compensator used in their place. FM
CAL should be set so that the DOLBY
TONE broadcast by the desired station
gives a DOLBY LEVEL reading on
the meters of the noise reduction
unit.
POPULAR ELECTRONICS
The perfect
gift for
anyone
For guys who like nothing better than to tackle a
challenging electronic project ... or just learn what
makes equipment "tick "...there's nothing better
than Popular Electronics.
because you're reading it!
You know that
But what about all the other people you know who
share your interest in electronics? Like the business associate who's fascinated by pocket calculators ...the neighbor who keeps refining his hi-fi
system ...the young relative who can't be parted
from his 2 -way radio. Are they getting Popular
-
who's mntö'
electronics
Electronics, too?
If they aren't, there's a way you can help them
out ... and save yourself a few dollars at the same
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at 30%
-
At that great rate, why wait? Order as many gift
and save $2.09 on
subscriptions as you like
each one! To do so, just detach the accompanying bound-in reply card. Fill in the names and addresses of the people you'd like to send Popular
Electronics to. Then just mail the card.
No need to send money now ... we'll bill you
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in your name.
OFF!
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47
Good AM- SSB -CW
performance
at a fraction of
a superhet's
cost
DIRECTCONVERSION
COMMUNICATION
BY JIM WHITE, W5LET
essential ingredient for the
neophyte in amateur radio is a
good receiver -one that is sensitive
enough to pick up signals that are
down near the noise level and selective enough to separate adjacent
signals and provide clear copy. Without such a receiver, one can only look
forward to "unanswered" CQ's and
lots of frustration. However, a good
communications receiver can cost
anywhere from $250 to $500, and most
beginners don't have that kind of
money. Even a good used receiver can
cost $150. As an alternative, a direct conversion receiver should be tried. It
performs well over a range of 3.5 to 4.3
MHz on AM, SSB, and CW and is easily
constructed at a cost near $30.
Direct conversion is a much neglected type of design that can best
be described by comparing it to the
more common system, superheterodyning. In the superhet system (Fig. 1),
the first stage is an r -f amplifier. This is
followed by a mixer where the signal is
AN
48
RECEIVER
combined with the output of a local
oscillator. The frequency of the latter
is a certain amount above or below
that of the r -f and the difference is
called the intermediate frequency.
The output of the mixer contains a
high- frequency component and a
low- frequency component.
These two signals are produced by
superheterodyning; that is, combining two signals to produce one at a
frequency equal to the sum of the frequencies of the original signals, and
one at a frequency equal to their difference. At this point we filter out the
high -frequency component and amplify the lower in a stage that has high
gain and a narrow passband, which
affords selectivity. The output of the -f
amplifier is sent to a detector, which
may be of two types: for AM reception,
it is an envelope detector (a diode followed by a low -pass filter); for SSB
and CW, a product detector, which is
really a second mixer, fed by a
beat frequency oscillator (BFO), is
i
used. The difference component of
this heterodyning process is an audio signal, which is then amplified through one or more stages and
passed on to phones or a speaker.
As you can see, there are usually
four or more stages that must be
properly tuned in conjunction with
each other for proper signal recovery
in a superhet receiver. Most quality
communications receivers have two
or three -f stages, with separate mixers, local oscillators, and tuned amplifiers for each stage. These complications drive the cost of receivers out of
the reach of a large portion of newcomers to the hobby.
The direct -conversion technique is
a much simpler process. The block
diagram of this system is shown in Fig.
1. The r-f amp supplies the mixer with
an amplified version of the signal received from the antenna. The mixer is
i
also fed an r-f signal of the same frequency as the incoming carrier from a
local oscillator whose frequency is adPOPULAR ELECTRONICS
cuits, which are the basis of the selectivity of the receiver's front end.
The other contributor of selectivity
in a direct conversion receiver is the
audio filter. This filter performs two
functions. It rejects the high -frequency component of the mixer output, passing the audio signal, and it
provides a large part of the receiver's
selectivity by virtue of its audio band pass characteristics. In this circuit, L3,
C5, C7, and C8 comprise the low pass
filter. Coil L3 is a variable TV width
coil, and the capacitors are of the
Mylar type.
Transistors Q2 and Q3 are conventional audio amplifiers, and almost
any npn silicon transistor will work
well in this circuit. Variable resistor
R10 serves as a volume control in the
standard voltage divider mode and
¡Cl serves as a high -gain audio output
amplifier. Any one of the common
audio modules furnishing 0.5 to 1 watt
output can be utilized for this purpose.
If desired, a headphone jack can be
installed as in Fig. 2.
A power supply was not incorporated into the receiver. A suitable
source supplying 500 mA at 9 volts
should be used. If you intend to use
the receiver for portable operation, or
don't wish to construct a supply, six D
cells in series will work perfectly. An
inexpensive plastic holder can be obtained for handling them. It is important to take care in observing polarities while connecting the supply. To
protect the sensitive semiconductors,
diode D2 has been incorporated. If the
wrong polarity is applied to the re-
justed by the main tuning dial. The
output of the mixer contains one
audio frequency signal and one r -f
signal at twice the frequency of the
original. The r -f signal is then filtered
out by a low -pass filter and we are left
with an audio signal. This is then amplified by one or more stages of high
gain and the output is connected to a
speaker or a pair of phones. That's all
there is to it. We have none of the
complexities of dual- or triple-conversion superhet receivers; but do
have good sensitivity, and if we use a
high -quality, narrow audio filter, we
have selectivity that will rival that of a
superhet unit costing ten to twenty
times more. The simplicity of operation is reflected in the ease of construction.
Circuit Operation. A comparison of
the block diagram (Fig. 1) and the
schematic diagram (Fig. 2) will point
out a few differences. For economy's
sake, an r -f amplifier has been omitted
from this receiver. However, the receiver is still sensitive enough to pick
up many signals that would be missed
with a cheap "communications-type"
superhet model. Signals from the antenna are coupled to the MOSFET
mixer, Q1, over the tuned LC circuit
composed of Li, C1, and C2. Transistor Q4 is the local oscillator and its
output is coupled through a small
silver mica capacitor, C28, to the second gate of Q1. The antenna coil, L1,
and the oscillator coil, L2, are wound
on small toroidal cores, which is an
effective way of attaining high Q cir-
ANTENNA
LPN -LEVEL
R -F
AMPLIFIED
DIFFERENCE
SUM RDIFFERENCE
AMPLIFIED
R
-F
COMPONENTS
AMPLIFIED
AUDIO SIGNAL
AUDIO
SPKR
LOCAL
OSC.
(A)
ANTENNA
LOW -LEVEL
R -F
SUM IR
AMPLIFIED R-F
R
-F)
DIFFERENCE(A-F)
AUDIO
-F
FILTER
AMPLI FIER
AMPLIFIED
AUDIO SIGNAL
AUDIO
AUDIO
AMPLIFIER
SPKR
LOCAL
OSC.
Fig. 1. Severn/ stages are tuned .simultaneously in superhet (A).
Direct -conversion receiver (B) is much simpler to operate.
NOVEMBER 1974
ceiver, D2 is reverse biased and will
not conduct. If this diode was not installed, the transistors and the IC
would be destroyed in the event of accidental reversal of power supply polarity. However, when incorrect polarity is applied, the receiver simply will
not work, thanks to the protective action of D2.
Construction Details. The receiver
was assembled on a 7" x 9" x 2"
aluminum chassis. Two separate circuit boards were used, and laid out on
the chassis as seen in Fig. 3. The two
cutouts for the boards should be made
following this scheme, but layout is
not critical. The use of individual
boards for the r -f and audio stages
eases troubleshooting as well as construction.
Mount the components on the audio
board first. When you have done this,
position the board in its cutout and
secure it to the chassis. Connect the
positive lead of the power supply to
the center -tap of the transformer and
the negative lead to the chassis
ground. Then connect a speaker to the
secondary of transformer T1. If you
have correctly assembled this board,
you will hear a hum or buzz from the
speaker when you touch the base lead
connection of Q3. The remaining
board can then be assembled and
mounted on the chassis. Try to keep
all leads as short as possible.
After the boards are in place, spray a
7" x 10" piece of 1/4" masonite with
aluminum paint. When it has dried,
mount the tuning dial on the panel,
and secure the panel to the chassis.
Mount the oscillator tuning capacitor,
C26, on a small bracket, and insert the
shaft of C26 into the dial drive
mechanism. After you have made sure
that the shaft is correctly lined up, fasten the bracket to the chassis. Using a
pair of pliers, turn the tuning
capacitor's shaft until the plates are
fully meshed. Then turn the dial to the
9 o'clock position and tighten the
setscrew on the shaft receptacle. You
can then log frequencies on the dial
using a crystal calibrator or an accurate VFO. The audio gain control, R10,
and the preselector capacitor, C2, are
mounted in 3/8" holes in the front of the
chassis. Drill the holes all the way
through the front panel. Three holes
must be drilled through the back of the
chassis, for the antenna and speaker
jacks, and the power supply leads. If
you choose to include a headphone
jack, it can be mounted either on the
front or the rear of the chassis.
49
R2
02
100K
C9
HEP -F2007
5pF
L3
QI
.01
C3
0
R4
R9
2.7K
2.2K
CS
RI
100
R3
0+
C4
20yF
C29
01SF
C6
+
C8
.026F
R6
3.9K
390,1
R13
47011
10jF
C16
""'"'".C19
R7
33K
TIyF
180pF
C27
50pF
_.+
014
R12
R25
33K
505F
C25
.IyF
.02yF
C30+I
.0055F
RII
39K
RIS
514
2.7 K
10011
RI9
100f).
cl5
.IyF
+ CI7
1
IO0yF
R20
21K
R SEE
.o1yh
TEXT
±
3yF +
C21
_
C22
C20
T
100
YF
IyF
T
q
C23
C1-200 -pF, 500 -V
silver mica capacitor
C2,C26- Variable 100-pF capacitor
C3-21 -pF, 50 -V disc ceramic capacitor
C4- 20 -pF, 15 -V electrolytic capacitor
C5,C8- O.02 -µF, 100-V Mylar capacitor
C6-50 -MF, 15 -V electrolytic capacitor
C7- 0.01 -pF, 100 -V electrolytic capacitor
C9, C10,C20
-pF, I5 -V electrolytic
capacitor
Cl I,C12,C13,C15,C22,C23- 0.1 -pF,
50 -V disc ceramic capacitor
C14- 10 -pF, 15 -V electrolytic capacitor
C16,C17,C18- 100 -pF, 15 -V electrolytic
capacitor
C19 -1 -pF, 15V electrolytic capacitor
C21,C29- 0.01 -pF disc capacitor
C24,C30-0.005 -µF disc capacitor
C25- 180 -pF, 500-V silver mica capacitor
C27-50 -pF, 500 -V silver mica capacitor
-5
C28
-5 -pF,
500 -V silver mica capacitor
D1 -1N914 diode
D2-Silicon power diode (100 PIV.
750
mA)
lCl-Integrated circuit (RCA CA3020)
J1- Chassis- mounting coax connector
J2-Phono jack
J3-Two -circuit phone jack (optional)
-34
from
L2 -34
turns No. 22 wire tapped 11 turns
ground end
turns No. 22 wire tapped 5 turns
from ground end
L3 -TV width coil, 10-50 mH (Miller 6319
or equivalent)
L1
Q1- Dual -gate
MOSFET (Motorola
HEPF2007)
Q2,Q3-2N3565 transistor
Q4 -JFET (Motorola MPF102)
R1-100,000-ohm
R3 -560 -ohm
J2
J3
r
.IyF
02
PARTS LIST
r°
SI
~+
9 VOLTS
R4-2200 -ohm
R5, R15, R 17, R 19 -100-oh m
R6-3300 -ohm
R7- 33,000 -ohm
All resistors
R8-390 -ohm
%-W, 10%
R9,R14- 2700 -ohm
Rl 1-39,000-ohm
R12-3900-ohm
R13 -470 -ohm
R16-470,000-ohm
R 18-4700 -ohm
R20- 27,000 -ohm
R10- 10,000 -ohm potentiometer
S1 -Spst switch (part or RIO)
TI-Transformer:
200 -ohm CT primary;
3.2 -ohm secondary (Calectro DI -729)
Note-Q1 ($1.65) and T50 -2 toroids (3 for
$1) are available from Circuit
Specialists, Box 3047, Scottsdale, AZ
85257.
Fig. 2. Receiver employs toroid- wound coils for LI and L2. QI is a dual -gate MOSFET.
Other Frequencies. The receiver
can also be used on other frequency
bands. Only the LC combination at the
input of the mixer and the tuned circuit of the local oscillator need modification.
For forty -meter operation, remove
C1. Remove L2 and replace it with 15
turns of No. 22 enamelled wire, wound
uniformly spaced on a T50-2 toroid,
and tapped 7 turns from the ground
end. Also, connect a 225 -pF silver
mica, 500 -V capacitor in parallel with
C25.
For twenty meters, remove Cl, and
wind a new oscillator coil, L2, on a
T50 -2 toroid core. It should be 71/2
turns of No. 22 enamelled wire, evenly
spaced, and tapped 21/2 turns from the
ground end. Remove the 225 -pF
capacitor across C25, if it was installed for 40 -meter operation.
50
For ten and fifteen meters, L1, the
antenna coil, must be replaced with 8
turns of No. 22 enamelled wire, wound
on a T50 -2 toroid core. Then L2 must
be replaced with 5 turns of No. 22
enamelled wire, tapped 2 turns from
the ground end. In winding both coils,
spread the turns to space them evenly
around the forms.
Alignment. Making sure that you observe correct polarities, connect a
9-volt power supply to the receiver.
Connect a speaker and antenna to
their respective jacks. Turn the audio
gain control until you feel it click, and
then advance it further until you hear
the "rushing" sound of atmospheric
noise. Rotate the preselector
capacitor, C2, slowly. At one point
there will be a noticeable increase in
sound from the speaker. Carefully ad-
just C2 for this peak. There is only one
adjustment for receiver alignment,
setting the value of inductance of L3.
This prevents any r -f components
from local oscillator feedthrough or
the heterodyne process from entering
the audio stages of the receiver. The
procedure is very simple. Adjust L3
until the tuning slug is positioned
about half -way into the coil. This completes receiver alignment.
Operating the Receiver.
As you
tune across a band, keep the front end
of the receiver resonant by adjusting
the preselector capacitor. You will
notice one basic difference in receiver
operation between the direct conversion receiver and a superhet. On the
conventional receiver, there is a mode
switch which must be adjusted for the
type of signal you want to receive.
POPULAR ELECTRONICS
Fig. 3. Etching and drilling
guides for audio and r-f
pc boards are at left and
bottom left. Component layout
guides for r-f and audio
boards are shown immediately
below and at bottom.
.1/
-4-0 F-LI-y
-s-c s
T
CHASSIS
02
D
8-C2---
OI
--R3
-0
-
S
GI
R2
-RI-4
'-'
C26.
R1
Cil
f
C24
1
SI
Jl,J3
1
CIO
02
C E
I
1
6
.R6-4
C23
-C224
-C6...
1
RI7
--05 -a
RI6
RIB
s-C3oi
--4
-C13
-
1
t
CI5
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S
R14--
R15
Î
1
+
5-C6--
03
E
----
RIO
R 13
WIPER
R5
C16
5-C14-44+
CHASSIS
NOTE
When this switch is in the SSB /CW
position, it activates the BFO and product detector. It is not possible to
properly demodulate such signals
when the switch is in the AM position,
which directs the signal to a simple
envelope detector. With the direct
NOVEMBER 1974
:
C7 MOUNTS ON LUGS
conversion receiver, no such switching is necessary and any signal (CW,
AM, SSB, or FM) is properly detected
just by adjusting the frequency of the
local oscillator, which is accomplished by turning the main tuning
dial.
Of L3
Thus, the direct- conversion receiver
provides many advantages over the
superheterodyne model. It is less expensive, easier to build, and simpler to
operate. Why not try something
different -you'll be pleasantly surprised.
51
CflNSTRUC?iON
Measure Low Millivolts
with a Multimeter
Range expander increases sensitivity by X10 or X100
HAVE you ever needed a simple
BY JOHN F. HOLLABAUGH
device that would let you expand the ranges of your multi meter so
that you could measure low- millivolt
ac and dc voltages? Perhaps you need
a small amplifier for checking out the
high -level inputs of an audio amplifier.
Well, the decade meter range expander described here will do both and
more.
The decade range expander can be
used to increase the usefulness of a
multimeter by adding ranges divided
by 10 and 100. It can also be used on
decibel scales, subtracting 20 or 40 dB
from the existing ranges in your VOM.
Use the expander as a sensitive signal
tracer to obtain quantitative measurements of the signal level at points
of interest, or to read voltage amplifier
stage gain directly in decibels on your
Owing to simplicity of circuit,
pc or perforated board
construction is equally suitable.
52
POPULAR ELECTRONICS
PARTS LIST
-9
-3
C2, C4 -1 -p.F,
AC
B1, B2
-volt battery
C1
-pF capacitor
15 -volt
ICI
-9V .41..le
electrolytic
capacitor
C3- 100 -pF capacitor
ICI -709 operational amplifier
1C2 -741 operational amplifier
J l J2-Phono jack
R1 -3900-ohm, 1/4-watt resistor
R2 -37 -ohm, 'h -watt resistor
R3- 1500 -ohm, 1 -watt resistor
R4, R11- 1-megohm,1/4-watt resistor
R5, R6- 10,000 -ohm, 1/4-watt resistor
R7- 10,000 -ohm trimmer potentiometer
R8, R9- 25,000 -ohm trimmer potentiometer
R10-100,000 -ohm potentiometer
R12- 100,000 -ohm linear potentiometer
S l -Spdt toggle or slide switch
S2 -Dpdt slide or toggle switch
S3 -Spst toggle or slide switch
S4-4- position, double -throw slide switch
Misc.-Chassis box, 9 -volt transistor battery clips, shielded cable and audio
phono plugs (for test cables). IC sockets or Molex Soldercons pc board or
perforated phenolic board and solder
clips, hookup wire, solder, hardware,
control knob, etc.
,
meter. You can even use the range
expander to measure the output voltage of a phono cartridge. Try that with
an ordinary multimeter.
About the Circuit. The range expander makes use of two operational
amplifier IC's (IC1 and IC2 in the
schematic), exploiting the particular
advantages of the types 709 and 741
op amps. A monolithic amplifier using
bipolar transistors appears to the
signal being processed as a series of
resistances and shunting capacitances. An RC system like this forms a
phase -shift network that at some frequency will cause the amplifier to oscillate.
Compensation is required to insure
low gain at the frequency at which oscillation occurs. The 741 op amp is
unconditionally compensated. (Gain
is reduced to unity at the point where
oscillation is possible.) The 709 op
amp is not internally compensated,
requiring external components to obtain the necessary compensation.
However, it can be compensated for
frequencies up to MHz, while the 741
is restricted to a top -end frequency of
about kHz by its internal compensation.
The 741 op amp has provisions for
input offset nulling, which makes it
operate well as a dc amplifier. In the
range expander, the 741 (IC2) is used
as a dc amplifier with output nulling
1
1
NOVEMBER 1974
R3
R6
10K
10K
u
ñ
..11; 91
9V
DC
51.1.- +9V
ZC2
5110.0-
-9V
id- II.
92
T9"
OU
J2
TPU
S3
DC
RI
IM
u
S2
EXP
DIR
AC
INPUT
I
R12
100K
R9
29K
-9V
Two
operational amplifiers (ICI and IC2) forra heart of expande,
and a feedback network that minimizes drift. The 741 has input over voltage protection and output short circuit protection, while the 709 has
neither. To próvide input overvoltage
and output short -circuit protection for
the 709, R1 and R2 are used.
The 709 (IC1) in the range expander
is compensated for a 40 -dB gain up to
about 200 kHz by Cl C3, and R3. It has
a feedback network consisting of R4
and R5. Both ac and dc amplifiers (IC1
and IC2) have a common vernier control (R12) that can be used where
exact values of gain are not required.
The incoming signal (or voltage) is
applied viaJl while the mode of operation (ac or dc) is selected with S2.
Switch S1 permits selection of X10 or
X100 in the dc mode, while switch S3
applies power to either the IC1 or the
IC2 circuit. The final switch, S3, permits the range expander to be bypassed when in the DIR position. In this
position, it routes the incoming signal
at J1 directly to output jack J2. (Note:
When S3 is in the DIR position, S4 can
be switched to off to conserve battery
life.)
,
,
Construction.Assemblingthe range
expander is relatively easy, owing to
the simplicity of the circuit. The entire
circuit can be easily accommodated
inside a 4 in. by 23/4 in. by 2 in. metal
utility box, with the four switches and
vernier control R12 mounted on the
.
top of the box for convenience.
You can use a printed circuit board
of your own design or perforated
phenolic board and solder clips for
mounting the ICI and IC2 amplifier
circuits inside thebox.JacksJl and J2
can be mounted at one end of the box.
When the circuit has been fully assembled and all parts are mounted in
place, use dry- transfer letters to label
the control, switches, and jacks.
Calibration. With the range expander switched to Dc (both S2 and S4 must
be set to this position) and R12 set for
maximum sensitivity, connect a multimeter set to a low- voltage range acrossJ2. Adjust R7 fora zero indication
on the multimeter's scale.
Connect a variable- output power
supply or a potentiometer in parallel
with a 1.5 -volt battery to J1 and adjust
the supply or pot for a 0.1- to 0.5 -volt
indication on the multimeter's scale.
Adjust R8 for an indication of 10 times
the reading of the input voltage level.
(Use the multimeter to monitor both
the input and output voltage levels.)
Now, decrease the output voltage of
the power supply (or battery /pot
setup) again for a meter reading of 0.1
to 0.5 volt and switch S1 to the X100
position. Adjust R9 for a reading of 10
times the previous meter reading.
With the input disconnected, recheck
the null produced by adjustment of
R7. If necessary, readjust the null. O
53
Build a
VERBAT/LE
DIGITAL LED
THERMOMETER
Low -cost, accurate device can be used as
indoor /outdoor thermometer
heater /cooler thermostat
temperature alarm
fishing thermometer
BY THOMAS R. FOX
digital thermometer described here was designed for
low cost and simplicity, as well as accuracy. If you check the semiconductor sales ads in this magazine and use
a conventional thermistor, you can
build the thermometer for about $15. If
you decide to use a precision thermistor, the cost will be about $20. Since
the thermometer operates from a
+5 -volt line, it can be used in a car,
THE
54
boat, or camper. With a line- powered
5 -volt supply, it can be used in the
home.
It is possible to use two switchable
thermistors to check temperature
differentials -such as between the
outside and inside, or between two
rooms. If a long lead is used between
the thermistor and the electronic circuit, the project can be used as a fishing thermometer.
How It Works. The frequency of the
CMOS multivibrator (Fig. 1) depends
on the resistance of thermistor TDR1,
which is determined by the ambient
temperature. Thus, if the temperature
goes up. the frequency of the multivibrator goes up, and vice versa. Trimmer potentiometer R23 is used to adjust the linearity.
The two -transistor multivibrator (Q1
and Q2) automatically resets the two
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26388
Fig.
1. Two
gates in 106 form multivibrator
whose frequency is determined by resistance
of'TDRI. Pulses (controlled by IC5, Ql, and
Q2) are counted by two- decade system IC1, IC2.
PARTS LIST
C1- 0.027 -µF silver mica capacitor
C2- 10-µF, 10 -V tantalum capacitor
C3- 320 -.iF, 10 -V electrolytic capacitor
C4- 15 -pF, 10-V electrolytic capacitor
DIS DI S2 -LED display (Monsanto
I ,
MAN -I or similar)
ICI. IC2-7490 TTL decade counter
IC3, IC4-7447 TTL decoder/7- segment
driver
105 -74121 TTL monostable multivibrator
decade counters (IC1 and IC2) and
/C5, which triggers the monostable
multivibrator. When /C5 operates, it
closes the CMOS AND gate and allows
the output of the temperature -dependent multivibrator to pass to the
counters. The length of time that IC5 is
on is determined by the value of C2
and the setting of R3.
Construction.
The circuit can be assembled on perforated board, using
sockets for the IC's and transistors.
Everything is on one board except the
power supply and thermistor.
Choose an enclosure that will accommodate the board, the power
NOVEMBER 1974
IC6 -Quad NAND gate (RCA CD4011
or similar),
JI. J2- Banana jacks
Q1, Q2-2N388, HEP641 or similar
Q3, Q4-2N404, HEP739 or similar
R1-2000-ohm. 5 %, 1/4-watt resistor
R2. R23- 5000-ohm miniature trimmer
potentiometer
R3- 50,000-ohm miniature trimmer potentiomer
R4, R7- 1500 -ohm. 1/4-watt resistor
R5- 50.000 -ohm, 1/4-watt resistor
supply, and the two readouts. Be sure
you have access to the three trimmer
potentiometers (R2, R3, and R23)
through suitable holes. If you use the
thermistor called for in the Parts List,
you can use an 1800 -ohm fixed resistor for R23. Other 1000 -ohm thermistors will require some adjustment of
R23. For stability, Cl should be silver
mica and C2 should be tantalum.
The on and off times of the display
are determined by the values of R5 /C3
and R6 /C4, respectively. These can be
varied to suit individual choice of
times.
If the temperature of more than one
area is to be measured, a simple
R6- 20.000 -ohm.
1/4-watt resistor
R8-R21 -100-ohm, 1/4 -watt resistor
R22- 22,000 -ohm. 5% 1/4 -watt resistor
TDRI -1000-ohm. negative coefficient
thermistor (USI 44004, available from
Yellow Springs Instruments, Box 279.
Yellow Springs, OH 43587)
Misc. -Suitable enclosure, flexible wire
for thermistor leads, rubber glue,
optional 9 -oz plastic jar and cover,
optional switch for two thermistors,
mounting hardware and sockets.
switching scheme can be arranged
between Ji and J2.
Carefully solder the flexible two wire cable to the thermistor and insulate the joints. If the thermistor is to be
used only indoors, coat it with some
rubber glue. If it is to be used outside,
it must be protected from the direct
rays of the sun and other weather
conditions. In this case, mount the
thermistor in a plastic jar (about 9 -oz
capacity), being sure to drill many
ventilation holes. The thermistor
(mounted through the cover) should
not come in contact with the jar. The
jar must be positioned so that it does
not get the direct rays of the sun.
55
Power Supplies. Three possible
power supplies are shown in Fig. 2.
Select the one that suits your needs.
Any 5 -volt supply that can deliver at
least 300 mA can be used. If the digital
thermometer is for fishing, use the
ac- powered circuit. In this case, omit
the transformer and diodes and use a
battery holder to mount four 1.35 -volt
mercury cells, with an spst switch to
control power.
Calibration. Connect the thermistor
to J1 and J2 and apply power to the
circuit. Allow it to warm up for at least
30 minutes. You will see a numerical
display that will "blink" as the multivibrator operates every few seconds.
Fill a glass with ice cubes and top it
off with cold water. Fill another glass
with water that is as close to 90 degrees as possible. (Use an accurate
mercury thermometer.) Set R23 to its
midpoint; and place the thermistor in
the ice water adjacent to an ice cube.
Without disturbing the glass or thermistor, adjust R3 until the display indicates 33. Place the thermistor in the
90° water. If the display shows greater
than 90, increase the value of R2 until
a reading of 90 is obtained. If the display indicates below 90, decrease the
value of R2.
Insert the thermistor back in the ice
water and touch up R3 if the reading is
less than 33. These adjustments will
have to be repeated several times to
THERMOSTAT CONTROL
will sound an alarm or turn on the
heat. Conversely, if the reference temperature is 99° and the sensed temperature rises to 101 °, Kl can sound a different type of alarm or turn on the cooling
system.
The use of a 5 -volt relay for K1 and
suitable connections for its contacts to
the heating /cooling controls produces a
state -of- the -art environmental control
K1
MODIFICATION
You can Convert the digital thermometer described in this article into a multi purpose heating /cooling thermostatic
control with a 0° to 99° F temperature
range by adding to it the circuit shown
below. Relay Kl and any alarm or circuit
connected to it can be made to trip at any
temperature selected by switches S1
through S8.
The reference temperature selected
by the switches is the sum of the closed switch designations. For example, to set
the system up for 34° F, you would close
system that eliminates troublesome
mechanical thermostats. For the most
reliable thermostatic operation, increase the value of C3 to at least 2000-pF
and change the value of R5 to 100,000
ohms. Also surround thermistor TDR1
with /4 -in. (6.35 mm) of insulating material and protect it from drafts.
S3, S5, and S6 (4° + 10° + 20° = 34 °). If
the sensed temperature falls below 34 °,
1
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AC
ADD -ON PARTS LIST
C5-0.5-pF disc capacitor
C6- 1000 -p F, 10 -volt electrolytic
itor
+5V
C7-- 3000 -pF,
20 -volt
itor
capac-
electrolytic capac-
C8- 10 -pF,
15 -volt electrolytic capacitor
D1,D2
ampere silicon diode (IN4001
or similar)
-:-
1C7,1C8-7485 magnitude comparator in-
tegrated circuit
1C9-7410 triple 3 -input NAND integrated circuit
1C10-7400 quad 2 -input NAND inter
grated circuit
IC 11 -7805 5 -volt regulator integrated circuit
Kl
-volt relay with spdt contacts
Q5 -2N388 (or similar) transistor
R24 -100-ohm, 1/2-watt resistor
Sl -S8 -Spst switch
T1- 12.6 -volt, 1- ampere filament transformer
-5
48R
+I2v
2W
IOyF
20V
_1_
+
T
JJ
3,IV
+5V
IyF
W
Fig. 2. Three typical power
sources for thermometer. Top
is for line power, other
two are for mobile operation.
56
get the readings as accurate as possible. If you encounter difficulty in attaining a linear display, adjust R23. In
general, a decrease of resistance in
R23 results in an increase in sensitivity
near the high end and a decrease in
sensitivity at the low end.
Once calibration is complete, the
digital thermometer should be within
1
degree between 0° and 90° F and
usable between -50° and 130°
F.
Al-
though this project was designed for
the 0 -90 range, it could be used to take
readings of temperatures below zero
and above 100° F. A reading of 90 on a
bitter -cold winter day would mean that
the true temperature is -(100-90) or
-10 °F. A display of 5 on a hot summer
day means the temperature is 100 + 5
or 105°
F.
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PART 2:
CONCEPTS AND CIRCUITS
of our short course in
logic, we discussed the binary number system, binary arithmetic,
and the octal number system. In Part 2,
we are concerned with logic concepts
PART
INdigital
1
and circuits.
Boolean Logic. In 1847, George
Boole, a British mathematician, published his Mathematical Analysis of
Logic. This booklet did not equate
mathematics with logic, but it did demonstrate how any logic statement can
be analyzed with basic mathematical
relationships. Boole published a much
longer and refined version of his theory
of logic in 1854. To this day, all practical digital computers and countless
other electronic digital circuits are
based on the concepts pioneered by
Boole.
Boolean logic (or algebra) makesthe
important assumption that
a
logic
statement is either true or false. Since
electronic circuits can easily be made
NOVEMBER 1974
to operate in either of two states, on or
off, it is convenient to equate "true"
with "on" and "false" with "off." Similarly, we can equate the binary 1 with
on and the binary 0 with off. With the
foregoing in mind, let us review
Boole's basic logic concepts.
The mathematical explanation of
0vr
OX/sO
logic put forth by Boole can be simplified into three basic logic functions:
AND, OR, and NOT. The AND function requires that one logic state or condition
and at least one other be true before
the entire statement is true. The OR
function requires that one logic state
or at least one other be true before the
/,tl=l
AND
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--o-+- Duz -0,..--our
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/
1. Switches are
arranged to illustrate
three basic digital
electronic functions.
Fig.
OR
NOT
57
entire statement is true. The NOT function simply reverses a stazement from
true to false, or vice versa. Electronic
NOT circuits are commonly referred to
as "inverters" because their function is
to invert the polarity of the signal.
The above definitions can be tabulated into a table such as shown in Fig.
1. Such a table is useful in showing the
relationships among Boole's three
logic functions and their electronic
and arithmetic counterparts. This type
of table is sometimes called a "truth
table" since it sets forth the various
logic conditions for which each statement is true. Generally, truth tables are
arranged in a more compact form similar to those shown for the three basic
logic functions in Fig. 2.
Truth tables can be created for any
logic function. Specification sheets for
digital logic circuits almost always include a truth table.
our
AB
ABOUT.
o /
o
0
0
0
O
/
O
/ /
I
ON: A
o 0
0 /
DUT.
0
/
/ 0 /
Our.
A O!/T.
0
/
/
O
/
I I
/
Fig. 2. AND, OR, and NOT symbols are
shown with truth tables.
Logic Symbols. Boolean logic
statements can be implemented by
simply writing them on paper, using
alphabetic symbols to correspond to
"true" and "false" conditions. Electronic logic diagrams, however, are
much easier to design and interpret if a
sort of block diagram of the circuit is
presented. For this reason, standardized logic -block symbols have been
devised for the three basic logic functions. They are shown in Fig.
2.
Compound Logic Circuits. Two circuit combinations (the
NOT -AND and the
are used so frequently that
they are treated as basic logic elements
and given their own logic symbols and
truth tables.
When the AND function is followed by
NOT -OR)
a NOT
statement, the meaning of the
function is reversed to NOT -AND,
commonly called a NAND function.
Similarly, when the OR function is folAND
lowed by a NOT statement, the meaning
of the OR statement is reversed to
NOT -OR, commonly referred to as a NOR
function. The logic symbols and truth
tables for the NAND and NOR functions
are shown in Fig. 3.
58
input B in the EXCLUSIVE OR circuit
shown
in Fig. 4. Since only one input is
OUT
B
enabled (input A), AND circuit 1 does
A B OUT.
A B OUT.
not turn on. Hence, a 0 is present at the
CARRY
output. OR circuit does turn on,
D / I
0 / O
since only one input need be present.
/ 0 0
/ 0 /
/ / 0
/ / O
Since the NOT circuit inverts the 0 from
AND
circuit 1 into a logic 1, AND circuit 1
Fig. 3. NAND and NOR symbols with
has two input signals and is therefore
associated truth tables.
turned on. The result is a logic 1 at the
suns output. (The circuit has added 0 +
DeMorgan's Theorem. About the 1 to obtain 1.)
same time Boole developed his logic
The EXCLUSIVE OR circuit is often
theories, Augustus DeMorgan was also called a "half- adder." Try verifying its
developing some fundamental operation yourself by adding 1 + 1 in
theories of logic. His most important binary.
contribution, known as DeMorgan's
Theorem, relates the AND, OR, and NOT
Practical Logic Circuits. Figure 1
functions as follows:
demonstrated how simple switching
A + B = A x B.
circuits can be used to implement each
A x B = A + B.
The arithmetic symbols + and x mean basic logic function. However, it is
OR and AND, respectively. The bar, or usually not practical to employ
vinculum, over a letter indicates the switches in real systems. Instead,
transistors, SCR's, tunnel diodes, or
NOT function. Thus A means NOT A.
The importance of DeMorgan's other solid -state switches are emTheorem is that an AND circuit contain- ployed.
The most commonly used switch in
ing a NOT at each input corresponds to
an OR circuit followed by a NOT. Simi- digital electronics is the transistor.
larly, an OR circuit with a NOT at each Relatively simple circuits that combine
input corresponds to an AND circuit fol- diodes, resistors, and transistors can
lowed by a NOT. This does not equate be used to implement the AND, OR, and
the NAND and NOR functions, but it does NOT functions. Thanks to integrated
mean that NAND circuits can be used to circuit (IC) technology, several or even
implement NOR functions, and vice dozens of individual logic circuits can
be placed on a single compact silicon
versa.
chip. Resistor -transistor logic (RTL)
Complex Logic Systems. Logic was once the most popular type of digisystems that contain three or more tal IC, but it has been largely replaced
basic logic elements are termed "com- by the more noise-immune transistor plex." One of the simplest of the com- transistor logic (TTL) type.
In recent years, field- effect transistor
plex logic systems is the EXCLUSIVE OR
(sometimes written xoR) function (FET) technology has been adapted to
shown diagramatically in Fig. 4. From integrated logic circuits of amazing
the truth table, note that this function is complexity. By insulating the gate of a
identical to the OR function with one FET with a layer of silicon dioxide, eximportant exception: A true condition tremely high impedances are made
exists only when one or the other con- possible. The result is a logic circuit
that requires microamperes or
dition, but not both, is true.
The EXCLUSIVE OR function com- nanoamperes of operating current at
pletes the connection between relatively low voltages.
Insulated -gate fabrication techniBoolean logic, the binary number system, and electronic switching circuits, ques are collectively known as MOS
for it can be used to add two binary bits. (for metal oxide semiconductor) techTo see how this is accomplished, as- nology. Since MOS transistors are unisume a logic 1 at input A and a logic Oat polar (p- or n -type) and do not require
separate p and n sections like conventional bipolar pnp and npn transistors,
MOS IC's can have a much higher
A
..r..u
CARRY
component density than most convenB
tional IC's. The result is large -scale integration (LSI). So, the next time you
read or hear the phrase "MOS LSI,"
Sv/4
you will know that it refers to a large scale integrated circuit employing
Fig. 4. Logic array for XOR circuit.
metal oxide semiconductors.
00/
00/
1
POPULAR ELECTRONICS
and AUX positions. Plugging a microphone into its jack automatically
disconnects the phono pickup and
applies a monophonic microphone
signal to the preamplifiers of both
channels. Another pushbutton switch
is for the high -cut filter, And for maximum convenience, there are two ac
outlets on the rear apron, one of which
is switched.
The Pioneer Model SX -636 AM/
stereo FM receiver comes complete
with a walnut- finished cabinet for a
fair -trade retail price of $349.95.
FM,
Product
Test Reports
PIONEER MODEL SX636 AM/STEREO FM RECEIVER
(A Hirsch -Houck Labs Report)
25- wattslchannel receiver with superlative stereo FM tuner section
Laboratory Measurements.
ROUGHLY in the middle of the
current line of stereo receivers
from Pioneer, the Model SX -636 features a tuner section that makes the
most effective use of integrated circuit
technology that we have yet seen in a
hi -fi component. The result is a level of
performance, in a moderate -priced
receiver, that in some respects sur-
passes that of most separate
components -to say nothing of far
more expensive receivers.
The receiver's audio amplifiers are
rated at 25 watts /channel over the entire audio range, with less than 0.5
percent THD. They are operated from
balanced positive and negative power
supplies and are direct -coupled to the
speakers. The preamplifier section
features tone controls with 11 lightly
detented click -stop settings, and a
balance control with a detented center setting. The phono preamplifier,
whose gain allows the rated output to
be developed with only a 2.5 -mV input,
can handle signals greater than 100
mV in amplitude without distortion.
The FM tuner section employs a
fairly conventional front end containing a FET r -f amplifier followed by a
dual ceramic -f filter featuring linear
phase characteristics. All other FM
functions are performed by a single
large-scale integrated (LSI) circuit- a
proprietary development of Pioneer,
containing circuitry that provides -f
amplification, five stages of limiting,
i
i
NOVEMBER 1974
and FM (apparently quadrature) detection. The detected signal then goes
to a phase -locked loop IC for multiplex
demodulation. The entire AM tuner
consists of only one IC, plus a handful
of external components. Consequently, Pioneer has made an AM /FM
tuner with only three IC's and a relatively small number of discrete corn ponents, the performance of which
proved quite exceptional in our
laboratory tests.
The receiver has two pushbutton
switches labelled TAPE MONITOR that
allow two tape decks to be used simultaneously, with off -the -tape monitoring from either deck and the ability to
copy tapes from one deck to the other.
The FUNCTION switch has a PHONO /MIC
position, in addition to the usual AM,
The
audio amplifiers of the Model SX -636
receiver clipped at 29.7 watts /channel
with both channels driven simultaneously at 1000 Hz into 8 -ohm loads. Into
4 ohms, the power was 36.7 watts,
while into 16 ohms, it was 20.5
watts/channel. The 1000-Hz THD was
less than 0.1 percent from 0.1 to 30
watts, typically measuring less than
0.03 percent. The IM distortion was
also less than 0.1 percent from 25
watts all the way down to less than 5
mW output.
At the rated 25 -watt output level,
and at one -half and one -tenth of rated
power, the distortion was typically
0.025 percent or less over most of the
audio -frequency range. It never exceeded 0.055 percent, this at full
'power and 20,000 Hz. At normal listening levels, the THD was about 0.01
percent. Our figures were a great deal
better than Pioneer's very conservative 0.5- percent published figure.
A 10-watt reference output level was
obtained with an input of 75 mV (Aux),
1.25 mV (PHONO), and 3.6 mV (Mlc). The
respective hum and noise levels were
81 dB, 75 dB, and 61 dB. The
inputs overloaded with
PHONO
a
100 -mV input, and the Mic input overloaded with a 275 -mV input.
The bass tone controls had a sliding
+10
MONO
----STEREO
0
I
I
I
I
I
I
I
I
I
III
AUDIO OUTPUT AT TAPE OUTPUT JACKS
O
dB =IVOLT
10
20
ÿ-J
30
W
4
ó
5
t1
60
70
80
PONEER SX -636
FM TUNER SECTION
t's
m
*
\_
*TOTAL
10
STORTION, NOISE, HUM
MOD. AT
-- -CIIPl - :i: - - L
11111111
I
-STEREO NOISE CURVE RISES ABOVE THE CURVE UNDER 205V BECAUSE WAVE
ANALYZER WAS USED TO EXCLUDE 19kHz PILOT SIGNAL
10
D
100
INPUT-MICROVOLTS OW)
NOISE
K
4K
10K
30K
59
111
o::::
mown
0.5
7.:::::
mmNNNI
PIONEER SX-636
1III
..1111 --LOW
=MOO
REFERENCE POWER
1
HALF POWER (-3tl0)
0.1
Ill
*INNII0II11
111111
NIMININNN
MNI NN
MMNIMNI_NNNNNNIMNI NNI
05
02
01
20
--
0.
11.,'11
POWER(-10EB)
1
0.2
PIONEER SX -636
-NNNN
N1I11
(25r)
%Á
11111111111
=MIMI
1'111111M1:1III
turnover frequency that allowed appreciable correction at the lower frequencies with no effect on the midrange. The treble tone control's
characteristic was hinged at about
2000 to 3000 Hz. Loudness compensation boosted both the low and the high
frequencies. The high -cut filter had a
6 -dB /octave slope, with the
-dB
point at 4700 Hz, while the RIAA
equalization was virtually perfect over
3
most of its range (less than ±0.25 dB
variation between 50 and 20,000 Hz).
There was a very slight bass roll -off
caused by the loading of the
10,000-ohm input impedance of our
graphic level recorder on the tape recording outputs where we made the
RIAA measurement. The cartridge inductance had only a moderate effect
on the equalization, about as much as
we have found on most other good
amplifiers. The microphone response
was essentially flat, within ±0.5 dB
from 25 to 6000 Hz, falling off to 1.5
dB at 10,000 Hz.
The FM tuner had an IHF usable
sensitivity of 1.8 pV in mono and 10 pV
in stereo. The 50 -dB quieting sensitivity was 3µV in mono and 100 pV in
stereo. Ultimate queting was 70 dB in
mono and 55 dB in stereo, while ultimate distortion was about 0.11 percent in mono (very low) and about 0.5
percent in stereo.
ROYCE MODEL
1 -600
111111111MIlllMEMiMIIII=W/ INIM.IIII
MIì;!111MMONMIiiC=.iliIIII
1111W
400
200
500
1kNa
Wiz
!kHz
FREQUENCY IN Hz (CYCLES PER SECOND)
10kNi
20
kH!
02
05
I
I
6
IO
PIONEER SX -636
FM STEREO
40
.y
20
50
CROSSTALK
100
10
20
50
400
200
500
IK
FREQUENCY
2K
dB at 100 Hz and 5300 Hz.
User Comment.
AVERAGE BOTH CHANNELS
SQ
5
modulator, which operate with remarkable effectiveness. The AM
tuner's frequency response was down
1
FREQUENCY RESPONSE
-60
2
CONTINUOUS AND EQU VALENT
SINE-WAVE POWER OUTPUT PER CHANNEL IN WATTS
+IO
-30
NNNINNNN
I1INNINNN 111N1I11
\NNNIN..T
NC17111MIIIININN7NIS NIIIINNINNIIMNINI111
- üiNlliìü - OII
iìü
11'lll-IM!
30
Illt.IIII
NNINNNINNNNNNNI
kHz TOTAL HARMONIC DISTORTION
14:111M DISTORTION
60/7000 Hz
CrmmLvoC7rNNNNNN.:111 1
NB-MENNO
NI
NN-_NINNN
Mi::a1111
-NN1111N
11111
.
----N1==
NNN gum
5K
IOK 20K
IN H2
The capture ratio was an impressive
0.7 dB, about the best we have ever
measured in a tuner. AM rejection was
51 dB. Image rejection was 75.5 dB,
alternate -channel selectivity was 63
dB, and muting threshold was 2.2
pV -the last low enough to exclude
noise but not any receivable signals.
Automatic mono /stereo switching occurred at 2.5 µV. The 19 -kHz pilot carrier leakage into the audio outputs
was 41 dB below full modulation.
The stereo FM frequency response
was within -±.0.25 dB from 30 to 13,500
Hz. It was down only 1.5 dB at 15,000
Hz. The channel separation was extraordinary, measuring between 50
and 53 dB over a frequency range of 30
to 2500 Hz. It reduced to 40 dB at
10,000 Hz and was still an extraordinary 31.5 dB at 15,000 Hz. Clearly, this
must be credited to the linear -phase -f
filters and the phase-locked loop dei
As the above test
data shows, the Pioneer Model SX -636
receiver merits the use of superlatives
in describing some of its characteristics. In particular, the stereo FM separation taxed the abilities of our signal
generator. In this one respect, the
system's tuner performed in a manner
that has been matched only by a component tuner that sells for $2500!
Impressive as our measurements
may appear to be, they cannot adequately describe the performance of
this receiver. It is not enough to state
that the receiver surpassed every one
of its published specifications during
our tests, even though this in itself is a
rather unusual event in our experience. The real proof is in the using.
The operation of the receiver is totally
smooth, with noise -free muting, very
accurate dial calibration, and not a
trace of switching transients or other
undesirable side effects. One can easily be lulled into taking these things for
granted, but it is surprising how many
audio components
all price
ranges -are deficient in some of these
important respects.
-in
CIRCLE NO. 65 ON READER SERVICE CARD
MOBILE CB TRANSCEIVER
Moderately priced unit features crisp speech quality
moderately price Model
-600 solid -state mobile CB
transceiver from Royce Electronics
features crystal- synthesized operation at full legal power on all 23 AM
channels. It has a meter that indicates
relative signal strength on receive and
relative output power on transmit. Additionally, the transceiver incorporates only the main essentials: adjustable squelch, a -f volume control, auTHE
1
60
tomatic noise limiting (anl), and
external- speaker jacks for receiver or
PA operation. Supplied with the trans-
ceiver are a detachable dynamic microphone and mobile mounting hardware. The rig is designed to be operated from 12- to 13.8 -volt dc, negative or positive -ground, electrical systems.
Retail price is $124.95.
The Receiver. The receiver section
POPULAR ELECTRONICS
of the transceiver employs double
conversion. The first -f is nominally at
10.6 MHz, while the second -f is at 455
i
i
kHz. The r -f stage ensures good sensitivity, which measured out at 0.3 pV
for 10 dB (S + N) /N. This is enhanced
by low -noise first and second mixers.
Six synthesizer crystals cut for frequencies between 37.600 MHz and
37.850 MHz provide heterodyning
signals for the first -conversion -f,
which occurs over a 40- kHz -wide
spread from 10.595 MHz to 10.635
MHz according to the heterodyning
crystal frequency used in relation to
the CB channel frequencies. Four
synthesizer crystals between 10.140
MHz and 10.180 MHz provide the
heterodyning signals for the second
conversion to the 455 -kHz -f.
Selectivity is obtained at the second
-f amplifier with a ceramic band -pass
filter which, together with the
receiver's a -f response, provided a
total response of 300 to 4200 Hz at the
6 -dB points.
Adjacent -channel rejection was
found to be at least 45 dB. Two
455 -kHz -f stages are used in an unusual setup that has two direct coupled transistors in lieu of the usual
transformer coupling. This permits
high gain to be obtained with good
stability.
The diode detector furnishes an agc
voltage that maintained an a -f output
within 12 dB with a 20 -dB r -f input
change (1 -10 µV) and 7 dB with a
60-dB input change (10- 10,000 µV). A
second diode provides a dc voltage in
accordance with the signal strength
i
and actuates the S meter, which registered S9 with a 100 -µV input signal.
The squelch, driven from the emitter
of the second mixer, was exceptionally smooth in operation. It eases
nicely in and out of operation without
"plopping." The squelch threshold
range was less than 0.5 pV to 1000 µV.
The a-f section consists of two cascaded stages, followed by a class -B
push -pull output stage that developed
bit more than 4 watts with 11 percent
distortion at the start of limiting when
driven by a 1000 -Hz signal into an
a
8 -ohm
load in both the receive and the
PA modes. When the a -f system is
used for PA work or for modulating the
transmitter, an extra speech amplifier
is switched into the system.
i
i
i
The Transmitter.
On transmit, one
of the four crystal signals, spotted between 10.595 MHz and 10.635 MHz, is
mixed with one of the six nominal
32.7 -MHz signals from the synthesizer
to generate the on- channel carrier. A
three -section bandpass filter at the
mixer's output minimizes spurious re-
sponses.
The rest of the transmitter consists
of an r -f amplifier, a driver, and the
power amplifier, with the two last
stages collector -modulated as usual.
A
three -section antenna -matching
network, plus a TVI trap, are incorporated into the power amplifier's output. Antenna switching is accomplished electronically. And no relay is
used for send /receive transfer.
The output power of the carrier into
a 50 -ohm dummy load measured 3.5
watts when the transceiver was operated from a 13.8 volt source. Complete
modulation of the carrier was obtained with 9.5 percent distortion at
1000 Hz. However, the positive peaks
did not reach the point where peak
power would normally be four times
the carrier power. On the other hand,
further raising the speech level extended the positive peaks to nearer
the full amount, with clipping occurring on both positive and negative
peaks to just 100 percent without
crossing over or overmodulation.
Under these conditions with the EIA
standard test tone of 2500 Hz, the
adjacent -channel splatter was 35 dB
down. With normal voice operation, it
was at least 55 dB down.
The normal overall a -f response was
300 to 4200 Hz at the 6 -dB points. The
frequency tolerance was 450 Hz or
better on any channel.
Comment. The Model
1 -600 Royce
CB transceiver is attractively styled,
with
a
wood -grain- finished control
panel and a chrome -finished bezel.
The edgewise- mounted S /power
meter is somewhat easier to read than
usual. It is illuminated in white on receive and switches to red on transmit
where it varies in brilliance in step with
the percentage of modulation.
The receiver is a relatively quiet one
which, with an effective and and crisp
speech quality on both transmit and
receive, make this transceiver well
suited for Citizens Band communication.
CIRCLE NO. 66 ON READER SERVICE CARD
PICKERING MODEL OA -3 STEREO HEADPHONES
(A Hirsch-Houck Labs Report)
Comfortable open -air phones provide "airy" sound quality
THE
Pickering Model OA -3 "openair" stereo headphones provide
little or no isolation from room
sounds. Unlike conventional isolating type phones that have air -tight seals
betweeen the ear -cups and the
listener's head, the Model OA -3
.
NOVEMBER 1974
phones are fitted with vinyl- covered
foam rings that rest lightly over the
ears. The lack of sound isolation
works in both directions. The program
being played through the phones can
be audible to others in the immediate
vicinity, as well as letting outside
sounds in.
Open -air phones have a distinctly
different sound quality than coven tional phones. The quality might be
described as "airy" or "light,"
perhaps because the normal room
ambience is not excluded from the
listener's ears (although it does not
directly interact with the musical
program as it does when listening
through loudspeakers). This type of
headphone is also exceptionally com-
fortable to wear, owing to its very light
weight of only 8.5 ounces (about 0.86
kg) and the slight pressure it exerts on
the ears and head of the person listening with them.
It is generally recognized that good
low -bass response through headphones requires a tight phone -to -ear
seal. While this statement appears to
contradict accepted acoustical theory
in the open -air design, it is not really
so. The bass response of an open -air
phone may extend down to 60 Hz or
so, but subjectively appear to go to a
much lower frequency. Since there is
little music content in the lowest octave of hearing, one is not aware of any
lack of deep bass sound when listening with good open -air headphones.
61
loin
"THE TROUBLESHOOTERS"
They get paid top salaries
for keeping today's
electronic world running
Suddenly the whole world is
going electronic! And behind the
microwave towers, push - button
phones, computers, mobile radio,
television equipment, guided
missiles, etc., stand
THE TROUBLESHOOTERS
- the men needed to inspect,
install, and service these
modern miracles. They enjoy
their work, and get well paid
for it. Here's how you can
join their privileged ranks without having to quit your job
or go to college in order
to get the necessary training.
'1+
flkfn
62
POPULAR ELECTRONICS
Just think how much in demand you would be if you
could prevent a TV station from going off the air by
repairing a transmitter ... keep a whole assembly line
moving by fixing automated production controls ... prevent a bank, an airline, or your government from making
serious mistakes by servicing a computer.
Today, whole industries depend on Electronics. When
breakdowns or emergencies occur, someone has got to
move in, take over, and keep things running. That calls
for one of a new breed of technicians The Trouble-
-
shooters.
Because they prevent expensive mistakes or delays,
and a title to match. At Xerox and
they get top pay
Philco, they're called Technical Representatives. At IBM
they're Customer Engineers. In radio or TV, they're the
Broadcast Engineers.
What do you need to break into the ranks of The
Troubleshooters ? You might think you need a college
degree, but you don't. What you need is know- how -the
kind a good TV service technician has -only lots more.
-
...
In Your Spare Time
Learn at Home
As one of The Troubleshooters, you'll have to be ready
to tackle a wide variety of electronic problems. You may
you
not be able to dismantle what you're working on
must be able to take it apart "in your head." You'll have
to know enough Electronics to understand the engineering specs, read the wiring diagrams, and calculate how
the circuits should test at any given point.
Learning all this can be much simpler than you think.
In fact, you can master it without setting foot in a classroom ... and without giving up your job!
For over 37 years, the Cleveland Institute of Electronics
has specialized in teaching Electronics at home. We've
developed special techniques that make learning easy,
even if you've had trouble studying before. Our AUTO PROGRAMMED® Lessons build your knowledge as
easily and solidly as you'd build a brick wall one brick
at a time. And our instruction is personal. Your teacher
not only grades your work, he analyzes it to make sure
you are thinking correctly. And he returns it the same
day it is received, while everything is fresh in your mind.
-
age components to let you perform 242 fascinating
electronics experiments. You learn the "how" as well as
the "why" of Electronics ... the Science of the Seventies.
Many leading companies use CIE courses to train their
own employees who are working on the latest electronic
equipment.
-
APPROVED UNDER G.I. BILL
All CIE career courses are approved for educational
benefits under the G.I. Bill. If you are a veteran or in
service now, check box for G.I. Bill information.
-
The Science of the Seventies
To keep up with the latest developments, our courses are
constantly being revised. CIE students receive lessons
in Field Effect Transistors, Digital Switching Units,
Microwave Systems, Lasers, Binary Coding and Computer Arithmetic.
In addition, CIE offers an exciting Electronics Technology with Laboratory course that includes 161 space-
-
or Your Money Back!
Get an FCC License
Two -way mobile work and many other types of troubleshooting call for a Government FCC License, and our
training is designed to get it for you. But even if your
work doesn't require a license, it's a good idea to get one.
Your FCC License will be accepted anywhere as proof
of good electronics training.
A good way to prepare for your FCC exam is to take
a licensing course from CIE. Our training is so effective
that, in a recent survey of 787 CIE graduates, better than
9 out of 10 CIE grads passed the Government FCC
License examination. That's why we can offer this
famous Money -Back Warranty : when you complete any
CIE licensing course, you'll be able to pass your FCC
exam or be entitled to a full refund of all tuition paid. This
warranty is valid during the completion time allowed
or your
for your course. You get your FCC License
money back.
Mail Card for 2 Free Books
Want to know more? Then fill out and mail reply card
or coupon today. We'll send you our two FREE books on
opportunities in Electronics. For your convenience, we
will try to have a representative call. Act now, and get a
high -paying job that much sooner.
CIE
Cleveland Institute
of Electronics, Inc.
1776 East 17th Street, Cleveland, Ohic 44114
Accredited Member National Home Study Council
r
Cleveland Institute of Electronics, Inc.
1776 East 17th Street, Cleveland, Ohio 44114
Please send me your two FREE books:
1. Your school catalog, "Succeed in Electronics."
2. Your book on "How To Get A Commercial FCC License."
Learn By Doing...
I
am especially interested
Electronics
Technology
Electronic
Communications
Electronics Technology
with Laboratory Course
teaches you the fundamentals. Using space -age
components and testing
techniques you will apply
the principles you learn
... actually analyze and
troubleshoot modern
electronics equipment.
NOVEMBER 1974
in:
First Class
FCC License
Electronics
Engineering
Broadcast
Engineering
Industrial
Electronics
Electronics Technology with Laboratory
Name
(PLEASE PRINT)
Address
State
City
Zip
Veterans and Servicemen:
Check here for G.I. Bill information.
CIRCLE NO. 7 ON READERS SERVICE CARD
PE-66
J
65
^HCKERING 0A -3 PHONES
FREQUENCY RESPONSE
FREQUENCY (Hz)
The published specifications of the
Model OA -3 phones indicate that they
are quite efficient, requiring only 0.1
volt across their nominal 15 -ohm impedance to produce a 100-dB sound
pressure level (SPL) at 1000 Hz. The
maximum rated input power is 0.2
watt /channel, but the series resistors
built into all amplifier headphone output circuits will provide adequate protection even with a high -powered amplifier. The distortion is specified at 0.5
percent for a 110 -dB SPL output.
The Pickering Model OA -3 headphones are supplied with an adapter
plug to permit them to be used with
small transistor radios and cassette
decks. Retail price of the phones is
$39.95.
Laboratory Measurements.
We
tested the frequency response of the
phones on a Koss -designed coupler,
which is a slightly modified version
of an accepted standard earphone
coupler. The measured frequency response of any headphone is closely
connected with the dimensions of the
coupler (or artificial ear) on which it is
mounted so that it is virtually impossible to compare data on different coupler designs, especially at the higher
frequencies. However, one can obtain
a reasonably valid picture of the
headphone's overall response even
though the specific peaks and dips on
the response curve may be as much a
property of the coupler as of the
phone (and would certainly be still different through the ears of any individual wearing the phones).
The measured frequency response
was relatively uniform from 100 Hz to
11,000 Hz, with a total variation of only
±5 dB over that range. The output fell
rather quickly at frequencies beyond
11,000 Hz and at a smooth 6 d B /octave
at low frequencies. The response was
measured with 1 volt applied to the
phones, producing an average 120 -dB
SPL over the measurement range,
which happens to agree exactly with
the published specifications.
Normally, one would expect distortion to be a function of frequency, but
the published specifications do not
specify the test frequency. We measured the distortion at several fre-
quencies between 200 Hz and 1000 Hz,
where the output was both strong and
smooth, at a 110 -dB SPL. The distortion was typically between 1.2 and 1.6
percent and was principally second
harmonic. In view of the high SPL
used, this amount of distortion cannot
be considered serious, even if it does
slightly exceed the published rating.
The electrical impedance of the
phones was an almost constant 20
ohms across the audio range. It gently
rose to 25 ohms at 150 Hz and underwent a slight drop to a 16 -ohm
minimum at 20 Hz.
Comment. Since our first experience
with open-air phones several years
ago, we have enjoyed their special
qualities -which eliminate many of the
objections voiced about headphone
listening (heavy weight and pressure
exerted, inability to hear desired outside sounds, such as the ring of a telephone, etc.). The Model OA -3 phones
embody all the virtues of a good
open -air headphone and have a
smooth response and the ability to
handle high volume levels without objectionable distortion.
The vinyl- coated ear cushions make
the Pickering phones a little less
"open" to outside noises than are
some other types that feature simple
foam pads. In fact, in a quiet room,one
might almost believe that the phones
are the isolating type.
The low impedance and high efficiency of the phones makes them exceptionally well suited for use with
small radio receivers and tape recorders.
CIRCLE NO. 67 ON READER SERVICE CARD
DRAKE MODEL SPR -4 COMMUNICATIONS RECEIVER
(A Hirsch -Houck Labs Report)
Versatile solid -state receiver for shortwave, amateur radio, CB
The receiver measures 121/4 in. deep
103/4 in. wide by 51/2 in. high (31.1 x
27.3x14 cm) and weighs 18 Ib (8.2 kg).
Its built -in 5-in. by 3 -in (12.7 x 7.6 -cm)
speaker is mounted on the left side of
the metal receiver cabinet. The price
of the Model SPR -4 receiver is $579.
Various crystal kits are available for
the amateur radio, marine, aeronautical, MARS, Citizens Radio, and other
special- interest bands. The external
optional speaker, 100 -kHz calibrator,
and noise blanker are priced at, respectively, $22, $20, and $65.
by
THE Drake Model SPR -4 solid -
state communications receiver
covers any 23 bands (each 100-kHz
wide) between 150 kHz and 30 MHz.
Thus, it offers the user reception of
international SW, amateur radio, and
CB radio transmissions,
others.
66
among
Technical Details. The receiver
employs a double- conversion superheterodyne design. Its first -f of 5645
i
kHz is obtained by the mixed product
of a crystal oscillator selected by the
band switch, while a stable per meability -tuned oscillator (PTO) takes
care of tlié' 4955 -kHz to 5466 -kHz
range. The PTO alone is used for the
lowest- frequency band.
Following the first mixer, selectivity
is provided by a crystal filter, and the
signal goes without further amplification to the second mixer. Here, it is
converted by a crystal oscillator (with
switched crystals for USB and LSB reception) to 50 kHz. Then a four-pole
LC filter and a tunable -notch filter
provide additional selectivity. After
two stages of -f amplification, the
signal goes to a product detector for
i
POPULAR ELECTRONICS
SSB and CW or a separate diode detector for AM. The audio amplifier is
rated at 3 watts output into a 4 -ohm
speaker load.
The PTO's dial is calibrated at 1 -kHz
intervals from 0 to 500, with about 50
kHz of "overrun" at each end. The
dial's reference mark can be shifted to
calibrate the receiver precisely to any
known frequency. At the upper center
of the receiver's front panel is a small
opening for the frequency range dial,
which is marked to indicate each of
the 10 basic bands, together with the
appropriate settings of the RANGE
switch and the PRESELECTOR control
knob. Decals are supplied for the 13
blank spaces on the dial, to be added
when other crystals are installed.
The front -panel controls include
concentric a-f and r -f gain controls,
mode switch (with positions for AM
CW, LSB and USB), and an accessory
switch. The last activates an optional
100 -kHz crystal calibrator and -f noise
blanker when they are installed. Concentric with the accessory switch is a
knob that is used to tune the rejection
notch filter through the -f passband to
,
i
i
reduce interference from heterodynes.
On the rear apron of the receiver are
phono jacks for the antenna and muting connections and an audio in /out
jack that can be used either to supply a
signal to a tape recorder, ahead of the
volume control, or to amplify an external signal through the SPR -4's amplifier. There is also a 120/240 -volt line
selector and a switch that disables the
dial lights for low battery drain (only
2.5 watts at 12 volts).
Laboratory Measurements.
The
Model SPR -4 receiver has sensitivity
ratings for a 10 -dB (S + N) /N ratio of
0.25 pV on CW and SSB and 0.5 pV for
AM at 30 percent modulation. We
measured the sensitivity at the center
of each band (except the two lowest
where the input impedance is too high
to match our signal generator). It
proved to be substantially better than
claimed and varied little from band to
band.
The CW sensitivity measured better
than 0.15 pV throughout and about 0.1
pV on most bands. The SSB sensitivity
was typically about 0.18 pV and
reached 0.22 pV on the highest and
lowest frequency bands tested. The
AM sensitivity was better than 0.35 pV
TIGER
and was typically a little better than
0.30 pV.
The agc is stated to hold the audio
level within 6 dB for an input signal
variation of 100 dB. We were able to
check it over only an 86 -dB signal
range, where it varied by only 3.2 dB.
-dB points
The -f bandwidths at the
were essentially as rated: 4.8 kHz on
AM, 2.4 kHz on SSB, and 0.4 kHz on
CW.
The dial calibration was within 1 kHz
on all bands, even without "zeroing"
the dial on each range as recommended. When we set the zero at
either end of the tuning range, the dial
was about as accurate as it could be
read -certainly within 200 Hz at all
points. And there was no discernible
6
i
drift over extended periods; the rating,
incidentally, is less than ±100 Hz.
The
S
meter is, of course,
a
relative
signal strength indicator. On the
band, an input of 1.8 pV gave an
S2 indication, while S9 was attained
7 -MHz
with only 17µV of input signal
strength. This is by any standards a
most "generous" meter. Furthermore,
a reading of S9 + 20 dB required 38
pV, which is only about 6 dB greater
than the S9 input. To reach S9 + 40
BASIC
"B"
POUTER
Now available, our latest version of the amplifier that started it all; the faithful old "Universal Tiger ". We have put
him in a fancy new chassis and added our famous complementary differential input circuit, but this is still the rugged, low distortion, economical amplifier that thousands of
you out there love so well. With a power output of 75 Watt
into an 8.0 Ohm load, or 90 Watt into 4.0 Ohms the
"Tiger B" is the ideal BASIC amplifier for all types of applications; from HiFi systems to public address work, to
instrument amplifiers; you name it. With its tremendous
frequency response, -1.0 dB at 1.0 Hz and 100KHz and
super low distortion of .05% I M at rated output, Tiger "B"
is ideal for almost any application using an audio amplifier.
TruTef
Nothing but the best components and first quality fibreglass circuit boards are used in this kit. The chassis is bronze
anodized and the perforated metal cover is standard.
275
POWER AMP
TÍ gel
For those who insist on "guilding the filly" we have an
accessory kit to add an output meter, input level control,
overheat indicator lamp, front panel power switch, etc.
Circle our reader service number for your free copy of our
latest catalog.
# 275 Amplifier Kit (single channel)
# AC -275 Accessory Kit
NOVEMBER 1974
$64.50 PPd
$ 7.90
PPd
ki-rh [-LA
Southwest Technical Products Corp.
219 W. Rhapsody,
San Antonio, Texas 78216
CIRCLE NO. 37 ON READERS SERVICE CARD
67
dB, we had to supply
a 5500 pV input,
which is actually 50 dB over the S9
input and 43dB over the S9 + 20 input.
Comment. The Drake Model SPR -4
receiver, in spite of its deceptively
simple appearance, is a highly sophisticated unit. It is not to be confused
with the many low- priced "communication receivers" directed toward the
young SWL and novice ham. It may be
simple enough to be operated by be-
ginners, but it is obviously meant
forthe advanced SWL, while also offering excellent flexibility for the intermediate and advanced operator.
The SWL in search of an elusive DX
station can set the dial to the station's
frequency with complete assurance
that he is tuned to what the dial says. In
addition, if his antenna and propagation conditions are right, he will surely
hear the station he is after-assuming,
of course, it is on the air.
If you plan to buy the Model SPR -4
receiver, we feel you should seriously
consider including the optional
crystal calibrator in your order. Without it, the receiver will probably be
tuned to within a kilohertz of the indicated frequency, but why settle for
that when it can be on the nose ?"
CIRCLE NO. 68 ON READER SERVICE CARD
AMERICAN CIRCUITS & SYSTEMS
MODEL MK1 FUNCTION GENERATOR
Sine, .square, or triangle waveforms from 6 Hz to beyond 1.25 MHz
e
0
THANKS
to low -cost integrated
circuits and new approaches in
design, a very important change is taking place in audio (and digital) signal
generators. Until fairly recently, audio
signal generators simply provided
sine and square waves that were variable in level and covered a frequency
range of about 20 Hz to 100,000 Hz.
The new "function" generators that
have begun to make their appearance,
by contrast, provide sine, square, and
triangle (or ramp) waves over a range
of about 10 Hz to 1 MHz and beyond.
One good example of a low -cost
function generator is the Model MK1
made by American Circuits & Systems,
Inc. The MK1 sells for $135 in kit form.
It is also available
factory -wired,
tested, and adjusted for $195.
The Model MK1 function generator
features sine -, square -, and triangle wave outputs that are selectable by a
WAVEFORM switch. The waveforms,
available at a pair of color -coded binding posts on the front panel, are continuously variable from 0 to 20 volts
peak -to -peak via an AMPLITUDE con-
trol.
Another
control,
labelled
can be used to provide 0,
20, or 40 dB or attenuation.
Built into the instrument is a dc
OFFSET control that permits the ac
signal to be dc biased anywhere from
+10 to 10 volt into an open circuit
( ±5 volts into 600 ohms).
Selecting a frequency is a two -step
process: First, the RANGE switch must
be set to the desired position (X10,
X100, X1K, X10K, X100K). Then, the
FREQUENCY control, calibrated in
equally spaced increments from 0.9 to
ATTENUATE,
68
11, is set for the desired frequency.
Hence, if you wanted a 50007Hz output
frequency, you would set the RANGE
switch to X1K and the FREQUENCY Control to 5. (The actual range of the MK1
is from less than 10 Hz to beyond 1.1
MHz.)
On the rear panel of the instrument
is a TTL output jack that provides a
TTL -compatible signal of the same
frequency as that at the OUTPUT binding posts on the front panel. The
logic -0 and logic -1 levels of this signal
are 0 and +5 volts, respectively.
(CMOS logic can be driven directly
from the OUTPUT binding posts.)
Also on the rear panel is a vCO input
jack that virtually doubles the versatility of the function generator. With the
appropriate inputs applied to this jack,
the output can be swept through a
range of frequencies, be frequency
modulated with tone or voice, or be
frequency shift keyed.
Within the instrument itself are six
IC's, two of which are precision voltage regulators, with the remainder
being linear devices. The power supply employs circuit -protecting fusing
and operator -protected three -conductor line cord.
Kit Details.
We selected the Model
function generator kit for our test
report. Upon opening the carton in
which it arrived, we were gratified to
note that all components were of preMK1
mium quality. Most of the resistors,
even some in noncritical parts of the
circuit, were of 5- percent tolerance,
while the trimmer potentiometers that
serve as hidden set -up controls were
of OEM quality. The large printed circuit board on which the majority of the
components are mounted is made
from G -10 epoxy fiberglass.
Assembly is simple and straightforward, guided by clear step -by -step
instructions and detailed drawings.
The only test instruments needed to
put the function generator into service
order are a multimeter (for the voltage
checks) and an oscilloscope (for dis-
tortion adjustments). A frequency
counter comes in handy, but is not
necessary, for calibration. (Three
methods of calibration are detailed in
the instructions.) Using the scope, the
sine -wave distortion can be set within
a few percent of optimum, while it can
be fully optimized with the aid of a
distortion meter.
After Assembly.
Once the function
generator was ready to be put into service, we subjected it to a few tests.
Using a precision frequency counter,
we determined that its frequency
range was from 6 Hz to 1.254 MHz in
five overlapping bands. The FREQUENCY control's dial calibration was
well within the specified ±5- percent
figure over almost the entire range.
The amplitude of the output signals
could be adjusted from 0 to slightly
more than 20 volts peak-to -peak, while
the dc offset was adjustable to its
specified ±10 -volt limits into an open
circuit. Triangle waveform linearity
was better than percent between 10
Hz and 100 kHz and about 2.8 percent
maximum from 100 kHz to 1 MHz.
Without using a distortion meter, the
distortion in the sine -wave function
averaged an excellent 6 percent.
When a distortion meter was used, the
figure could be optimized at 2.4 percent. All other specifications were met
or exceeded.
1
Comment.
The American Circuit &
Systems Model MK1 function generator is an excellent buy, particularly
in kit form. It offers a quality and versatility that should appeal to the audio or
digital experimenter and service tech-
nician.
CIRCLE NO. 69 ON READER SERVICE CARD
POPULAR ELECTRONICS
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CAREER
OPPORTUNITIES
FOR THE
TECH REP
BY ALLAN C. STOVER
'f you read an ad like the above
in the classified section of your
newspaper, you might think it was too
good to be true. However, it accurately
describes many technical representative and field engineering opportunities available in the electronics
field. On the whole, a tech rep job pays
well, offers excellent opportunities for
travel, and encompasses a number of
duties.
A tech rep is hired by an electronics
company which, in turn, sells his services where needed. The U.S. Government, private industry, and local and
foreign governments sometimes need
electronics technicians for special
projects. So, they often sign a contract
for enough tech reps to get the job
done. The contract might call for the
tech reps to do anything from teaching a Job Corps class in New Jersey to
manning a lonely tropospheric scatter
site in Thailand.
On the job, a tech rep's work varies
from assignment to assignment. On
one assignment, he might be an advisor, telling a crew of workers what to
do. On his next assignment, his job
might be to teach a group of students
or working technicians the theory and
operation of new avionics equipment.
Then again, he might operate and
maintain a communications system.
Most tech reps are called upon to do a
bit of everything. In a typical month, he
might spend a few days each at teaching a class in electronics theory and
practices, helping out on installing or
NOVEMBER 1974
renovating electronics gear, and repairing a radio or radar system.
Tech reps have been known to operate, maintain, and repair computers,
avionics equipment, radar gear, corn munications systems, test equipment,
navigational aids, and just about everything else that uses electronic circuitry. One tech rep might specialize,
his duties confined to repairing a
single complex transceiver model,
while another might be called upon to
repair a dozen or so different models
and types of equipment. Some tech
reps specialize in teaching.
An assignment might put a tech rep
in the heart of downtown Manila, right
in the midst of civilization. On the
other hand, assignment locations can
be lonely and far from the amenities of
civilization, such as in the heart of a
jungle or atop a mountain. Assignments can be almost permanent or
highly mobile, depending on the contract. Some tech reps stay in the same
location for years, while others must
pack up and move to a new location
every few months.
Most tech reps enjoy their assignments, but few find "paradise." The
Manager of International Recruiting
for Page Communications Engineers
says, "One word of caution to those
who are tempted to cast all aside and
dash off to unknown places: To the
neophyte who expects to find all the
creature comforts he is accustomed
to, my advice is to look before he
leaps. Instead of some pleasurable
off -duty relaxation in exotic Bankok,
he might find himself repairing a radio
(transmitter) on an isolated mountaintop in Iran."
Electronics companies employ
thousands of tech reps, stationing
them in every corner of the world. You
can find tech reps in almost every
state of the Union, Germany, on the
island of Crete, in Taiwan, Ethiopia,
and Iran, Vietnam and Korea, Spain,
Turkey, the Philippines. New Guinea,
Jamaica, the Arctic, and on some
Pacific islands, and aboard ships and
submarines.
RCA Service Co. Technical Services
representative works on radar unit.
s
What and Where. ITT's Federal Electric Corporation ships their tech reps
all over the world. Sometimes they include tech rep services as part of a
contract for new equipment. In December 1973, Federal Electric signed
$56- million worth of new contracts
and renewals, which gives an idea of
the size of the corporation's operations. Here are a few of the hundreds
of jobs the Federal Electric tech reps
have handled:
They have installed a microwave
communications system in South
Vietnam. (The South Vietnam government issued a stamp in their
honor.) In Italy, Germany, France, Belgium, England, and the Netherlands,
they installed a tropospheric scatter
system. For years, they have operated
and maintained DEWLine (Distant
Early Warning Line) sites ranging from
Iceland and Greenland to northern
Alaska in some of the bleakest and
frostiest locations inhabited by man.
The Federal Electric Corporation has
held this contract since 1956 -almost
two decades.
Federal Electric tech reps per-
formed operational and maintenance
services as the prime contractor on
the Air Force's Western Test Range,
where they manned range tracking
ships and stations, among other
things. They installed a computerized
reservations system in the British
Overseas Airways Corporation's offices in New York.
Tech reps from RCA Service Company have tackled hundreds of different jobs in as many different places all
over the world.
A satellite ground station was installed in the People's Republic of China.
They operated and maintained a tracking site in the Arctic, and they operated and maintained missile tracking
stations on islands in the Atlantic
Ocean for the Air Force's Eastern Test
Range.
The RCA teach reps gave technical
assistance and training to the Philippine, South Korean, Ethiopian, and
Spanish air forces.
Salaries and Extras. Most companies pay their tech reps well. Base
pay usually is on an average with a
RCA Service Co. Government Services Technician
works on Meteorological Data Handling System
Center's computer control console at the
Goddard Space Flight Center.
good technician, but "extras" can
push the total -package up to more
than what the average electronics engineer earns, from $10,500 to $19,000
per year. Overtime can run these figures even higher. The extras depend
on the company the tech rep works for
and the assignment on which he is
sent. Examples of extras include:
Per Diem: A daily allowance that is
designed to repay the tech rep for
most of his extra expenses. It covers
hotels, meals, cleaning bills, tips, and
other expenses. Per diem is usually a
flat rate; so, if a tech rep cuts corners,
he can pocket the money he saves.
The per diem rate runs from a few dollars up to and beyond $25 per day.
Some companies pay per diem for as
long as the tech rep remains on the
assignment, while others pay it for
three to six months only. Still other
companies pay per diem only when
the tech rep travels on business away
from his regular assignment. A few
companies pay the tech rep's actual
expenses instead of per diem.
Cost -of- Living Allowance (COLA): A
few companies pay COLA to cover the
difference in living costs between a
U.S. city and an overseas location. The
COLA in Tokyo, the world's most expensive city in which to live, can run
hundreds of dollars a month. One
company gives a flat 30 percent of
base pay no matter where they assign
a tech rep. Some U.S. Air Force contracts direct the local military disbursement officer to pay a COLA to
each rep. COLA can start at $7 per day
on some contracts.
Bonuses: Some companies pay a
flat bonus for overseas service. It can
be 10 percent of base pay or $125 per
month, depending on the company for
which the tech rep works. Some corn panies pay a bonus that depends on
the location of the assignment; a tech
rep who lives in a soggy tent in South
Vietnam gets a bigger bonus than one
who works in downtown Brussels.
This patchwork of pay and allowances makes it difficult to predict a
tech rep's pay package. But the average paycheck for tech reps, all extras
considered, runs from $12,000 to
$16,000 per year, with some reps receiving salaries above and other
below these figures.
The tech rep who works overseas
has an opportunity to take advantage
of one of the juiciest Internal Revenue
tax laws ever written. If he spends 510
days (about 17 months) out of 18
months outside the U.S., up to $20,000
POPULAR ELECTRONICS
of his yearly income during that period
is tax -free! If his company withholds
any taxes, the tech rep claims a refund.
Other privileges sweeten the picture
even more. Most military contracts
with overseas assignments grant the
tech rep most of the privileges of a
captain. This means that he can live in
the Bachelor Officers Quarters, eat
and drink in the Officers Club, and
shop in the PX and commissary.
The company handles the tech rep's
transportation to his assignments. In
return for paying per diem while the
man is en route to his assignments,
the company requires him to spend at
least a year on assignment. Should the
tech rep decide to terminate his employment before the year is up, he
must pay back all the company spent
on getting him to his assignment.
Becoming a Tech Rep. The qualifications for becoming. a tech rep are
surprisingly light. Only a handful of
positions call for an engineering degree. Most require only technician level electronics training and three to
five years of specialized practical experience. If you worked on a new system in the armed forces, no matter
what your rank, you stand an excellent
chance of landing a tech rep job. Many
companies train some tech reps, but
most prefer to hire the man who already has the knowledge and practical
experience to go right to work.
If you live near an electronics company that hires men for tech rep positions, apply in person. Alternatively,
you can type up a resume and mail it
to the companies that hire tech reps
and field engineers. (Consult the want
ads in your newspaper for addresses.)
If
your background fits in with
have received or earned.
Who Needs Tech Reps? Scores of
large and small companies need qualified men to serve as tech reps. As a
rule of thumb, try the large companies
first. If you think you can qualify for
the work, you might try the following
three companies first:
Federal Electric Corp., 621 Indus trial Ave., Paramus, NJ 07652. (Address correspondence to the attention
of Mr. Ridings, Director, Field Services.)
Page Communications Engineers,
Inc., Vienna, VA 22180. (Attn.: Manager, International Recuiting)
RCA Service Co., Camden, NJ
08101.
If these companies do not need your
talents, try Bendix, Philco -Ford, and
Kentron.
Walt Ostrander, Audioanalyst,
As SeenThroughTheEyes
Of His A-100X Speaker.
a
company's needs, you will receive a
job application form in the mail or be
hired on the spot. (When making up
your resume, keep it down to two
pages. Just give the facts about education and experience and some personal data.)
The personal data in your resume
should include full name, age and date
of birth, marital status, state of health,
and dates of military service, if any.
Under education, list all schools you
attended in which you received training for the type of work you are applying for. Include resident, home-study,
and military courses taken, detailing
the titles of the courses and types of
equipment you studied.
When giving details of your work
NOVEMBER 1974
experience, start with your present
position and work back in time. List
job titles, the dates you held the positions, and short descriptions of your
work duties. List the names and model
numbers of all the equipment with
which you are familiar. Also, mention
any achievements and awards you
His tortures drive drivers to drink.
d
This perfectionist believes
results justify the individual
bench testing of every single
assembly. "Unusually flat
toward the top of its price
range" says High Fidelity
of our A -100X bookshelf
speaker. We say, a SixYear
Warranty on every speaker in the Audioanalyst
line, $94 to $249.
Everyone boasts clean highs, low
bass, a better driver. Fact.The
best drivers are pretty much
alike. It's what our Audio-
analysts do with them that's different. Is there
a percentage in this kind of obsession? A sound
one to be sure.To test our speakers. simply
write to us. All we ask is that you give them what
we give them.The works.
Meet the Audioanalyst Master of Torture.
Live! At the Boston High Fidelity Music
Show -Room 412.
(Audioanalyg)
Brookfield, Conn. 96604
Monstrous About Perfection
P.O. Box 262,
CIRCLE NO. 44 ON READERS SERVICE CARD
71
There's a new Heathkit
everyone on
The Heathkit Digital Color TV is for
two kinds
of people
... those
who understand
electronics, and
those who don't
People who understand electronics
will appreciate the GR- 2000's advanced digital design, incorporating
on-screen channel readout
and optional clock. Digital
logic circuitry programs
up to 16 stations in any
sequence. Then just
press a button -you'll
never have to switch
through a "dead"
`\,1
channel again.
And our exclusive
:'
,000``
VHF /UHF varactor
tuner eliminates clunking
contacts that corrode and noisy motors that break down.
The GR -2000 also has
the industry's first
fixed -filter IF amplifier. There's no
need for instrument
IF alignment ever, so
the picture stays bright
and clear year after year. And even in
urban areas where stations
are packed closely
together, there's virtually no adjacent
channel interference.
The 100% solid -state
chassis uses 19
integrated circuitsmore than any other TV
around. You'll get
superior performance and reliability
no conventional set can match.
A built -in dot generator and test meter
make it easy to keep the GR -2000 in
peak condition without expensive
service calls. The slide -out service
drawer and hinged, swing -out chassis
-
72
put everything in easy reach. If anything ever goes wrong, an extensive
trouble- shooting guide will help you
fix it.
And people who don't understand
electronics will enjoy the best looking
picture around. Popular Electronics
said the picture on the 25" (diagonal)
screen "can only be described as superb. The Black (Negative) Matrix
CRT, the tuner and IF strip, and the structions, prefabricated wiring harvideo amplifier provide a picture equal nesses, transistor and IC sockets and
to that of many studio monitors..."
modular circuit boards greatly simEveryone likes the on-screen readout plify assembly.
that puts the channel number into the See the TV the experts are talking
picture whenever you want it. When about. Popular Electronics summed it
you change channels or touch the re- all up: "In our view, the color TV of
call button, the big, bright digits the future is here -and Heath's GRreappear. Add the optional clock 2000 is it!"
module and you'll see the time as well GR -2000 -the TV everyone can apas the channel.
preciate.
The optional wireless remote control Mail order price for chassis and tube,
makes the GR -2000 even more enjoy$669.95. Remote control, $89.95, mail
able. Change channels, adjust the volorder.
ume, set tint and color intensity and
Cabinets
turn the set on or off from across the
start at
room. And, a touch of the Volume bar
$154.95,
automatically returns the digital readmail
out to the screen momentarily. It's an
order..
amazing handful of convenience.
(Retail
Even if you don't have a lot of kit prices
building experience, you'll enjoy the slighty
higher.)
GR -2000. Illustrated step -by -step inPOPULAR ELECTRONICS
Christmas gift for
new
your list Our
Heathkit
Give your scientist, engineer or student a gift he'll use all year long.
Finger -sized keys and 8 bright 1/2" digits make it easier to use than pocket
calculators. Cumulative memory and
register exchanges virtually eliminate
scratchpad work. Performs arithmetic
plus trig and arc trig in degrees
or radians, common
and natural
logs,
Desktop
Electronic
Sliderule
Solves Your
Gift- Giving
Problems
New Heathkit Electronic
Clock/Timer for Car,
Boat or Plane
A timely
gitt-
an electronic clock and a 20 -hour rally
timer, both with quartz crystal accuracy. Bright 1/2"-tall digits dim automatically at night. 12 VDC, mounts on or
under dash. Kit GC -1093, 2 lbs., mail62.95*
able
Two Heathkit Electronic
Clocks with Standby Power
powers of e,
square roots,
inverses, pi
and exponential
functions.
Kit IC -2100, 4 lbs.,
mailable ..119.95*
New Heathkit
Aircraft Strobe
A bright idea for the pilot on your list
Unique New Heathkit
-or for anyone who needs an emergAM /FM Digital Clock Radio
ency marine or marker light. It meets
Our outstanding clock radio makes FAR 23.1401 and
even sleepy Santas happy.
assembles easily in
just one evening. For
12 VDC neg. ground.
With clear lens,
optional red
and red /clear
lenses available.
Kit OL -1155, 3 lbs.,
mailable ....54.95*
The electronic clock with snooze
alarm features a gentle "beep" with
adjustable volume. Or wake to the Learning's Fun With Our New
component -quality AM/FM radio.
Heathkit "Electronics Workshop"
Standby batteries (not included) keep
the clock on time during power inter- The JK -18A teaches kids electronics
ruptions. Kit GR -1075, 10 lbs., mail- the easy learn -by -doing way. 35 excit129.95* ing projects include light meter, sound
able
meter, transistor radios. For safety,
it's battery
powered and
requires no
soldering.
(Batteries not
included) Kit
JK -18A, 10 lbs.,
mailable ..34.95*
NOVEMBER
1974
Two beautiful gifts -the GC -1092A is
a clock with a snooze alarm; the GC1092D reads the time in 6 digits, the
month and date in 4 digits. Both have
standby power to keep the clock on
time without the display even during
temporary power interruptions. (Batteries not included.) Kit GC -1092A or
D, 5 lbs., mailable
each 82.95*
......
Time /Alarm
Time /Date
Heathkit Exhaust Analyzer
Checks Your Car's Tune Up
Make everyone's Christmas whiter and
cleaner -be sure your tune up is helping clean up the environment. Big 41/2"
meter reads
relative
combustion
efficiency,
air -fuel
ratio and
percentage
carbon monoxide.
Kit CI -1080, 6 lbs., mailable ...59.95*
75
Exciting new Heathkit
Christmas giving
new Heathkit
dual-trace DC-l5MHz scope
Compare the features:
Dual -trace with true X -Y
capability
1 mV /cm vertical sensitivity
over the full bandwidth
Post-deflection accelerated CRT
for bright trace, fast writing
Vertical amplifier delay lines for
pulse analysis capability
Digitally controlled triggering
for exceptional stability
Typically triggers up to
-
45 MHz guaranteed to
30 MHz
It offers a
lot more than
just a low price
The Heathkit 10 -4510 is your best
'scope buy for two good reasons
does more and it costs less.
Time base sweep up to 100 nsec /cm.
There's always a reference baseline,
even when there's no trigger signal.
The time base can be precisely triggered at any point along the positive
or negative slope of the trigger signal.
In automatic mode, it triggers at the
zero crossing point.
Modes of display. Either channel can
be displayed as a function of time or
both can be displayed together. In
X -Y operation, channel 1 provides
horizontal deflection and channel 2
provides vertical deflection. There are
22 calibrated time bases from 0.2 sec/
cm to 0.1 ,.sec /cm. The sweep speed
is continuously variable between
switch positions. Any speed can be
expanded five times by pulling out the
control knob.
For easy calibration, a 1 volt peak -topeak square wave is available on the
front panel. The regulated supply operates from 100 -280 -volt AC power.
Kit 10 -4510, 34 lbs., mailable 549.95*
Assembled SO -4510, factory -wired &
calibrated version of the 10 -4510, 34
750.00*
lbs., mailable
New Low -Cost Heathkit
each step. Attenuator accuracy is ±1
dB; frequency accuracy is ±3 %. Non linearity of the triangle waveform is
5% max., symmetry is within 10 %.
Sine wave THD is 3% max. from 5100k Hz. Square wave rise and fall
times are 100 nsec max. 105 -130 or
210 -260 VAC. Kit 1G -1271, 7 lbs., mail99.95*
able
Assembled SG -1271, factory-wired &
calibrated version of IG -1271, 7 lbs.,
140.00*
mailable
-it
Function Generator
A true function generator, not an oscillator, delivers sine, square and triangle waveforms from 0.1 Hz to 1
MHz. Short -proof output supplies 10
volts peak -to -peak into 50 -ohm load.
A calibrated step attenuator adjusts
from 0 -50 dB (10V to 30 mV) in 10 dB
steps. A variable control provides up
to 20 dB of additional attenuation at
76
POPULAR ELECTRONICS
projects -timed for
Coming in December...
A new
generation of
Heathkit ham
radio equipment
-
1
New Heathkit 5- Function
SB -634 station console
High-power match for the SB -104. Lowest cost
conduction cooled linear on the market. 1200
watts PEP and 1000 watts CW from less than
100 watts input. It's also rated at 400 watts input for slow-scan TV and RTTY. And absolutely
silent no blowers, no fans.
Full metering of relative power, plate current,
grid current and plate high voltage. Safety features include microswitch interlocks for top and
bottom shells, thermal shutdown, fused cathode,
on /off switch with circuit breaker for power
transformer.
On the air in 15 to 20 hours. Fast, easy assemno
bly, then check it out with an ohmmeter
alignment necessary. Kit SB -230, 40 lbs., mail319.95*
able
a 24 -hour 6 -digit
Five accessories in one
electronic clock, a ten -minute digital ID timer
with visual and /or audible alarms, RF wattmeter, SWR bridge, hybrid phone patch with manual and VOX controls. Kit SB -634, 14 lbs., mail179.95*
able
-
New Heathkit SB -104 transceiver
Years ahead in design & features the SB -104
is a complete rethinking of what a CW /SSB
transceiver should be. It utilizes the latest digital & solid -state technologies. The "104" is completely solid -state from the front end to the RF
output.
Totally broadbanded. You can switch from 3 to
30 MHz without preselector, load or tune controls.
True digital readout with 6 bright digits to indicate the frequency with accuracy to 100 Hz.
Mobile- ready. The SB -104 operates from 12
VDC, so it's ready to go mobile when you are.
Optional features include a plug -in digital noise
blanker and 400 Hz crystal filter for CW.
Just about the only things that aren't totally new
about the "104" are the quality and easy assembly that have made Heath famous. Kit SB -104,
669.95*
31 lbs., mailable
Kit SBA -104-3, 400 Hz CW crystal filter for SB104,
34.95
Ib., mailable
Kit SBA -104 -1, digital noise blanker for
Ib., mailable
SB -104,
24.95
Kit SBA -104 -2, mobile mount, 6 lbs.,
mailable
........34.95*
New Heathkit SB-230 1 kW
conduction -cooled linear
-
-
New Heathkit SB -644 remote VFO
Designed exclusive for SB -104, it provides the
ultimate in multi -mode operation with two crystal sockets for fixed frequencies. No modifications just plug the VFO into the "104" and go
VFO frequency even reads out on the 104's
digital display. Kit SB -644, 10 lbs.,
119.95*
mailable
- -
station monitor scope
New Heathkit Fixed station
AC power supply
How clean is your signal? The bright 11 x 2"
screen helps you keep your rig in peak condition. Reveals a wide variety of operating probnonlinearity, insufficient or excessive
lems
drive, carrier or sideband suppression problems,
regeneration and key clicks. Monitors AM, SSB
and CW signals up to 1 kW from 80 to 6 meters.
139.95*
Kit SB -614, 17 lbs., mailable
New Heathkit SB -604
New Heathkit SB -614
-
Powers the SB -104 from 120 or 240 VAC. Sophisticated regulation assures almost. no change
in voltage from no load to full load. Entire supply fits inside SB -604 speaker cabinet. Kit HP89.95'
1144, 28 lbs., mailable
station speaker
Response-tailored to SSB
and designed to match
the SB -104. Large enough to
house HP -1144 AC power supply.
Kit SB -604, 8 lbs., mailable ....29.95
.F
1
........
r
HEATH
Heath Company, Dept. 10 -11
Benton Harbor, Michigan 49022
Schlumberger
Send for your FREE 1975 catalog today.
Please send my free 1975 Heathkit Catalog.
Please send the merchandise checked below. I've
plus shipping, in payment.
enclosed $
,
-
HEATHKIT ELECTRONIC CENTERS
Units of Schlumberger Products Corporation
Retail prices slightly higher.
ARIZ.: Phoenix; CALIF.: Anaheim, El Cerrito, Los
Angeles, Pomona, Redwood City, San Diego (La
Mesa), Woodland Hills; COLO.: Denver; CONN.:
Hartford (Avon); FLA.: Miami (Hialeah), Tampa;
GA.: Atlanta; ILL.: Chicago, Downers Grove; IND.:
Indianapolis; KANSAS: Kansas City (Mission); KY.:
Louisville; LA.: New Orleans (Kenner); MD.: Baltimore, Rockville; MASS.: Boston (Wellesley
MICH.: Detroit; MINN.: Minneapolis (Hopkins)
MO.: St. Louis (Bridgeton); NEB.: Omaha; N.J.
Fair Lawn; N.Y.: Buffalo (Amherst), New York City
Jericho, L.I., Rochester, White Plains; OHIO: Cincinnati (Woodlawn), Cleveland, Columbus; PA.:
Philadelphia, Pittsburgh; R.I.: Providence (Warwick); TEXAS: Dallas, Houston; WASH.: Seattle;
WIS.: Milwaukee.
GR -2000 Color TV
JK -18A Junior electronics
GRA- 2000 -1 Digital
workshop
clock module
GRA -2000 -6 TV remote
GC -1092A Digital clock
with snooze alarm
control
GC-1092D Digital clock
Calculator
CI -1080 Exhaust analyzer
GR -1075 Digital
clock radio
GC-1093 Digital car
clock /timer
with date display
IC -2100
(assembled)
1G -1271 Function
generator (kit)
SB -644 Remote VFO
HP-1144 AC power supply
SB -604 Station speaker
10 -4510
Oscilloscope (kit)
Name
Address
State
City
'Mail order prices,
lip
FOB factory
Prices and specifications subject to change without notice.
L
CL-541
J
CIRCLE NO.
NOVEMBER 1974
SO -4510 Oscilloscope
SG -1271 Function
generator (assembled)
SB -104 Transceiver
SB -104 -1 Noise blanker
SB -104 -2 Mobile mount
SB -104 -3 CW crystal filter
SB -230 1 kW linear
SB -614 Monitor scope
SB -634 Station monitor
5
ON READERS SERVICE CARD
77
COMPUTER TERMINALS ARE COMING
BY LESLIE SOLOMON
Technical Editor
THE sales and complexity of electronic calculators seem to be
rising exponentially. Practically every
month, new models appear with more
functions available. Some of the new
ones are more like mini -computers
than calculators.
Where will it all end? Someday,
each of us will probably have his own
full -blown computer. For the foreseeable future, however, such a computer
would be a trifle large for the average
home; and the price would be out of
reach for almost everyone. But there is
a way of having the use of a full -blown
computer without buying your own.
All you need is a "computer terminal."
A computer terminal looks like a
desk calculator, has a typewriter
keyboard with a few extra keys, and is
equipped with alphanumeric readout.
The terminal shown in the photo is
typical of those now being made available at reasonable cost. The input/
output connections to the terminal are
made through some form of conventional telephone-line coupler. For the
unit shown here, the coupling is made
by dropping the phone into a special
cradle.
To operate a terminal, the user simply dials his local time -shared
computer company (usually found in
the Yellow Pages) and places the
phone in the cradle. The remote computer then "answers" the phone; and
after the terminal operator enters his
private billing number and the
computer verifies it, the operator is
signalled to start his entry. What can
the operator do? Just about anything
of which the expensive computer on
the other end is capable -which is
quite a bit.
Since the computer is expensive,
operating time costs would be very
high if it were not for the use of "timesharing" techniques. This means that
a number of terminals are using the
same computer but sharing its time.
The computer switches from one terminal to another so fast that it appears
that each terminal is the only one
using the computer. This lowers the
user price to between $9 and $30 per
month installation fee plus anywhere
from $2 to $8 per hour of actual computer time. The user also pays conventional telephone rates for the use of
78
the line, just as he would if he were
making a conventional call.
It might appear that the hourly use
charge is high. However, if a problem
is laid out first, it takes very little time
for it to be typed in; and then the answer should return within seconds. A
lot of information can pass through
such a system in a couple of minutes.
Then, the time used is cumulative.
That is, the user pays only for the accouple
cumulated computer time
of minutes here, a couple of minutes
later, etc. The system does not have to
be operated for an hour at a time.
What can a computer do for you?
Obviously it can provide a complete
household or business accounting
system in which all purchases, sales,
etc., are broken down into various
areas for tax purposes. A record of all
financial statements, income, expenses, material, etc., is kept in the
electronic files. With an available
memory of up to 100,000,000 words,
quite a bit of information can be stored
for future recall by the customer.
How good is security? Can some
outsider get a look at your private
files? Precautions are generally taken
-a
to prevent unauthorized readout.
Each customer has a private entry
code that he alone can use to gain
entry to his portion of the computer.
This private code is never displayed on
the alphanumeric readout so it remains a secret even if someone is
watching the operator at his console.
Some time -sharing companies have
special "programs" for their subscribers. Some companies, for example, specialize in engineering areas,
supplying subscribers with a list of
programs available. The program
might be a complete analysis of a particular problem, and all you do is insert
your own numbers. You do not have to
be familiar with the mathematics involved; the computer takes care of
that. For example, assume a transistor
amplifier is to be designed or a band pass filter using an op amp is needed.
When you call the program, the terminal readouts will "ask" certain questions regarding input, voltages, stage
gain requirements, output desired,
and so forth. Once you insert your requirements in answer to the computer, your circuit will be designed in
seconds, with all components identified. It is like having an engineering
textbook come to life, solving all the
problems and supplying all the answers.
There are educational programs for
children in which the computer takes
on the role of teacher. Children can
learn math or other subjects and ask
all the questions they want from a
teacher having infinite patience. The
computer will "talk back" when the
student does something wrong, explain the problem, or give the correct
answer.
There are also "game" programs in
which various sports or games can be
played between the computer and the
operator. This is a powerful learning
tool for students and an intellectual
exercise. There will be programs in
almost every area; and, as the library is
expanded, notification will be sent to
each subscriber.
What about cost? The MITS Corn puter 256 terminal is $595, complete
with the acoustic coupler. This particular terminal will store 256 characters with expansion to 1026. Options
to expand up to 3 pages are available.
An auto -transmit feature allows the
user to transmit data or program material line -by -line instead of typing it
directly into the computer, thus saving
actual computer use time. The terminal also has a tape play /record feature
that gives it a virtually unlimited memory capability. Almost any type of tape
recorder can be used.
If you already have a digital computer, a hard wire connector is provided
for direct connection to your own
computer. If you don't own a computer, this connector will be used for
some future add -on features to further
expand the terminal.
The MITS Comte). 256.
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DX
Listening
By Glenn Hauser
"SECRET" SW STATIONS
AS winter approaches,
static on
the 2 -3 -MHz band declines, allowing us to hear some well -known
broadcasters. Low -powered stations
in Latin America, Africa and the
Pacific inhabit the 120 -meter tropical
band (2300 -2495 kHz); high -powered
outlets in China and both Koreas
spread beyond this range.
Usually closer but offering no less a
challenge to DX are the secret shortwave stations! So secret are they that
even the people operating them are in
the dark (or if they are aware, they
hope no one will notice).
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MAIL-FROM
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Department 217S
12 East Delaware
Chicago, Illinois 60611
312-664-0020
CIRCLE NO. 20 ON READERS SERVICE CARD
80
We're talking about harmonics of
mediumwave (standard AM broadcast) stations. By combining a good
antenna and receiver system with lots
of diligent delving into the residual
noise level, you too can intercept
these secret flea -powered broadcasts.
Even in the central USA, the great
majority of harmonics heard originate
in Latin America; this speaks highly
for the harmonic -suppression standards of the FCC, probably the most
rigid in the world.
A harmonic is not just any off frequency reception of a station. It
must be an exact integral multiple of
the fundamental. Second harmonics
(twice the fundamental) are by far the
most common, since progressively
smaller amounts of power are radiated
as harmonic numbers go up.
The way to DX harmonics successfully is to know the 1.6 -3.2 -MHz band
-so you can quickly eliminate everything that isn't a DX harmonic. If you
live near a nighttime MW station, you
probably can't help but hear its second and /or third harmonic. Whether transmitted, or the result of receiver overload on the fundamental, local
harmonics are of no DX interest.
If you live near two or more nighttime MW stations, their mixing products may be audible. You can predict
where most of them will show by
summing each pair of fundamental
frequencies, and by doubling one, and
then subtracting another, in all possible combinations.
You can also eliminate any transmission not consisting of programming, such as hams, LORAN, radiolocation beeps, time signals, ship and
shore, military nets, aircraft, RTTY,
etc., etc.
This leaves the legit 120 -m broadcasters. In the evenings, you'll hear
mostly Venezuela, Brazil and Haiti;
and Mexico and Guatemala fight it out
only on 2390 kHz. Any other pro-
gramming just about has to be harmonic!
When you suspect a harmonic, divide the measured frequency by 2 or 3
to see if its fundamental matches up
with a known station. Then tune to the
fundamental frequency; chances are
you won't hear it there, but if you do, it
should be under entirely different
conditions of interference, fading and
strength. Such a check will prove that
you are receiving a transmitted harmonic, propagated on the frequency
where you find it.
Don't give up if at first you don't
succeed; the selection of harmonics is
continually changing as different stations tweak their traps. Do report your
harmonic DX to other enthusiasts, but
not to the station! Once they learn
their harmonic is getting out, they just
might be moved to eliminate it permanently. Let's keep the secret.
DX Monographs. The National
Radio Club has become quite a publisher, not only for its members but for
a wider readership. Over the past few
years, NRC has published many technical articles about antennas suitable
for mediumwave reception. Now,
they're compiled in the NRC Antenna
Book, the first of many reprint books
to be issued. You'll find everything
from the portable ferrite rod to the
mile -long Beverage wave antenna, including much ado about loops: direct
coupled, degenerate, balanced, unbalanced and box. The 60 -page book
is $2.25; and many other individual article reprints are available too. For a
list, send an SASE to NRC, Box 127,
Boonton, NJ 07005.
DX Courtesy. Back in the heyday of
radio, many MW stations went on the
air in the wee hours with special programs for DX listeners. The practice
still continues, thanks to a small band
of enthusiasts in the NRC, International Radio Club of America, and
Newark News Radio Club -the clubs
most involved in MW DX. Each has its
own "Courtesy Programs Committee"
(CPC), but they coordinate their efforts to avoid duplication. Most CPC
broadcasts occur on Monday mornings during the winter season, when
24 -hour stations take a few hours off.
But the tests are scheduled for the
most open "window," as determined
from the NRC Log's schedule section
and continually revised "condition of
frequencies" lists. Each club publishes calendars of upcoming spePOPULAR ELECTRONICS
cials. The astute late -night MW DX'er
can add stations and states he might
never hear any other way. It's all arranged by volunteers, which means
there would be more such DX specials
if there were more volunteers (hint,
hint).
Plug ìn...wire.
PAT. PENDING
Europe on Your Clock Radio?
Trans -Atlantic (TA) MW DX usually
peaks during October and November;
the exact dates depend on solar variations. Several days of low A- indices
(below 10) broadcast on WWV at 18
past the hour signal optimum conditions. You'll have a much better
chance to hear Europe on the BCB if
you're in the eastern half of the continent. Most European channels are
"split" between ours, so powerhouses
of 300 to 1200 kW can even come
through an 'all- American five' if you
tune just right. The band usually
opens from the top downward, so
check 1586 for West Germany, 1554
for France and 1466 kHz for Monaco
just after local sunset and again
around midnight. But watch out for
buzzes from nearby TV sets which also
show up on split frequencies. Later on
in November or December the socalled "Midwinter Anomaly" puts a
damper on this high -latitude MW DX.
Pings & Bursts. Before we go, some
tips for vhf people. November and December are among the best months
for meteor scatter DX'ing. High -gain
antennas on FM and TV will reveal
`pings' every few minutes on just
about any morning; the diurnal peak
of MS is at 6 a.m. local mean time.
Chances for more strong, long `bursts'
are markedly greater during the
meteor showers: Orionids, October
18 -23; Leonids, November 14 -18; and
best of all, the Geminids, December
10 -14. If you're lucky enough to catch
a burst during a test pattern or ID
break, you've bagged a new station
-even if the reception only lasts a few
seconds. This happens more often
than you might think. If you're not
equipped for this esoteriç signal
snatching, you can still look out for
winter sporadic E openings; check the
lowest open TV channels each evening, especially in December and
January. For vhf DX'ers in Gulf coastal
states, this is the time for thousand mile uhf hauls or trans -Gulf Mexican
vhf. You'll find much more on television DX'ing in the POPULAR ELECTRONICS
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marine radio and turned the CB transceiver to channel 9. Even as blindly
called for help knew it was futile. The
channel was clobbered with meaningless conversation and interference.
Seven pairs of eyes watched me work
the radio, expecting some official response that would deliver us from an
I
I
CB Scene
increasingly threatening situation.
flicked from channel 9 to explore the
rest of the band, searching for a strong
carrier of any station, but the CB
speaker emitted a persistent chorus of
squeals, static and fragmented voices.
Then, as the selector indented on
channel 11, the S -meter shot up the
scale. A strong, clear voice filled the
cabin. knew must land this station or
I
By Len Buckwalter
CB TO THE RESCUE
AFTER holding a license for
16 years it finally happened. was
saved by CB! In a remarkable boating
incident last summer, got a first -hand
look at CB's vast power to do good
and evil. Good because CB sped to the
rescue faster than the U.S. Coast
Guard. Evil because of the Neanderthal types who prowl the band tearing up communications, emergencies
included. But let's start at the beginning.
It is the end of a hot Sunday in July
on Long Island Sound, a body of water
east of New York City and between
Long Island and Connecticut. After a
weekend of cruising aboard a rented
32 -foot houseboat, two happy, tired
families gather in the bow to witness
our arrival in the harbor. The entrance
at the breakwater is alive with craft
converging on a narrow channel that
leads to a crowded anchorage over
the next two miles. As the houseboat
penetrates a few hundred yards into
the harbor the steady rumble of the
I
I
engines stutters, then weakens.
I
glance down at the tachometers just
in time to see the needle for the starboard engine flicker, then fall over and
die on zero. Not much cause for alarm
because a twin -diesel boat like ours
can easily limp home on one good engine. Ten seconds later the port engine also expires.
Late Sunday afternoon in summer is
no time to lose power near the entrance to Stamford harbor, known as
the "boating capital of the Sound." It
is home for some of the country's most
glittering corporations and boasts
more Sir Thomas Lipton types than
you'd find at the Queen's Tea. Woe
betide any craft under 40 feet that's
bobbing in the right -of -way. But there
was just enough momentum in the
houseboat's lumbering hull to swing
the craft in a semicircle and pull its
prow to the edge of the busy channel.
Luckily, the anchor bit the bottom before the wind could smash us against a
sailboat moored a few yards away.
86
Miraculously, within minutes,
a
flashy cabin cruiser glides alongside
and asks what's the matter. High on its
flying bridge a lady captain grips the
handset of a marine radiotelephone,
ready to call the harbor police, the
Coast Guard or anyone else we want.
We're so awed by this Amazonian
Marine that our grateful mumblings
are drowned by the sound of her orders barked into the handset. Within a
few seconds she triumphantly announces, "The Coast Guard is on its
way!" Worried wives breathe easier,
children return to their play and the
men stand proudly on the deck of the
crippled vessel, knowing that everyone will soon be safe at home.
Ten minutes later a rickety putt -putt
with "Coast Guard Auxiliary" hand painted on its side pulls up. It was a far
cry from the 40-foot government cutter we were expecting to take us in
tow. What's more, the two lads aboard
this brave, but hardly adequate,
launch were enroute to more serious
business offshore. A cruiser had run
out of gas and demanded immediate
assistance, which meant our rescuers
would not return for two hours.
But the surging stream of yachts,
hot -rodders and hundreds of other
Sunday drivers brushing past our bow
was clearly dangerous. In the waning
twilight there would be a sharply increased threat of collision. As the
houseboat wallowed in the wake of
passing boats, decided to try my
hand at the two radios aboard
marine two -way rig and a CB set -and
attempt to reach the owner of the boat.
Maybe he could tell me how to restart
the engines. We had already poured in
5 gallons of reserve fuel from a jerry
can with no luck.
The vhf marine radio was hopeless.
The circuits to the New York Marine
Operator were jammed with returning
boats wanting to call home, forcing
the besieged operator to put new callers on standby. It might take hours to
reach the owner.
switched off the
I
-a
I
I
I
I'd be lost.
"Break- break," said, then waited.
After monitoring this station a few
minutes, it was clear that nothing
about its operation was legal. The
communications were chit -chat, its
callsign just a contrived fake. But the
operator answered my break and
suppressed any thought of rules and
regulations. The voice, which sounded like that of a 16 -year old boy, said
he'd gladly help me out of the emergency -but then uttered the words
dreaded. The young man wanted me
to stand by while he contacted a volunteer team located closer to me. This
was the last thing I'd do. We would
almost certainly lose each other in the
nightmare of interference washing
over the band that evening. Somehow
I'd have to convince him of this.
Suddenly a third voice moved on the
frequency. "What's the emoigency ?"
it asked. Some goon had been listening to me describe our plight and
committed the cardinal sin of any distress communications; getting on the
frequency without being called and inI
I
I
terfering with communications.
I
couldn't hear what the young man replied but the goon didn't like it. He
used foul language and held his carrier steadily on to block our signals.
The young man knew what to do, He
ignored the carrier and shrewdly said
several times, "Switch to channel 12."
His powerful signal punched through
just enough so could understand the
words. It worked. We rejoined on
channel 12 and heard no more interference. Now the only problem was to
convince the young man to stay with
me and not attempt to raise a closer
station. My plan was to give him the
I
phone number of the boat's owner
and have him put through a collect
call. Somehow he balked at the idea.
By now the sun dipped below the
POPULAR ELECTRONICS
horizon and boats crossing our bow
had switched on their running lights.
The gathering darkness was adding
yet another problem, didn't want to
dock the houseboat in the dark. Even
in daylight, maneuvering this big tub
at slow speed called for plenty of engine reversing and bursts of power to
keep it from splintering the dock.
"Do not turn me over to any other
station. I'd like you to make a collect
call for me."
shot those words at the young
operator with the sting and authority
of an army drill sergeant. It was my
only hope. must have shook up the
kid because he came back on, no
longer sounding like a NASA space
communicator. assured him several
times that a long- distance telephone
call placed collect would cost him nothing.
"I have Jim on the line. He says try
the lift pump." A wave of excitement
flooded over the houseboat. The
young man had raised Jim, the boat's
owner, on the landline and the first
instructions were coming through.
"Where's the lift pump ?" asked.
Questions and answers went back and
forth over our primitive phone patch.
Jim, the owner, would say something
to the young man on the phone, and
the information was relayed to me via
CB radio. It worked well, except for
the tense moments when Jim and the
young man spoke to each other on the
landline and no carrier filled the air.
grew apprehensive at the possibility of
some other spoiler getting on the
open channel and jamming us. To
prevent it, turned on my carrier during the pauses and made blind anI
I
I
I
I
I
I
nouncements
about emergency
communications in progress.
the channel clear.
It kept
In the stern of the boat, hatches
were raised to expose the two dead
Volvo diesels. Following Jim's CBsent directions, we rammed the lift
pump up and down by foot until it
forced fuel into the starved engines.
turned the starter key and watched the
tachometer. It bounced crazily as the
engine fired, but dropped back to
zero. gripped the CB mike, shot my
next question at Jim. My words raced
over water by radio for a dozen miles,
were repeated by the young CB
operator on the phone, then travelled
by landline over 60 miles to Jim's
home.
"Keep pumping while the engine is
turning," Jim said. He was right; the
houseboat shuddered, made several
explosive sounds then throbbed with
the steady power of its 310 horses.
"Up anchor," shouted, and within
minutes the houseboat melted into the
endless stream of other boats heading
up the channel to a safe landing.
Later that night learned what killed
the engines. Fifty gallons were in the
fuel tank but this boat had a quirk;
when the tank was about a quarter full,
the fuel line would gobble air and not
feed unless the passengers stood at
the stern. Those lift pumps purged the
trapped air in the lines to get the fuel
I
LARGE-LARGE
I
DISCOUNTS
LOW -
PRICES
flowing again and, with the crew
herded on the stern, the engines ran
perfectly.
wanted to thank the anonymous
young operator. He had done an excellent job of extricating us from a tight
situation, especially when he switched
us away from the QRM. But can't express much gratitude because he has
no call, no license and no CB status.
He legally doesn't exist.
The second hero of this adventure is
CB itself. Our lives were not in immediate danger, but each passing
minute increased the risk from scores
of other craft that careened down the
narrow channel in the dimming twilight. CB, in fact, came through when
about a half -dozen other resources
failed. First, it outdid that vigilante
who was first to arrive on the scene.
She was a well- meaning Good Samaritan, but she couldn't provide our most
immediate need
tow into port.
Then there's the U.S. Coast Guard and
its auxiliary. Despite their heroic work
in boating areas, our dilemma held too
low a priority. Next, the marine telephone system
too, was seriously
overloaded. Then there was harbor
police, but the men in blue never
materialized. This is one happy instance where CB outdid them all! Q
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Amateur Gear
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NOVEMBER 1974
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CIRCLE NO. 40 ON READERS SERVICE CARD
R1
MAC'S SERVICE SHOP
The Simplest
Test Gear
By John T. Frye, W9EGV
what are you doing with the tattle lights ?"
Barney asked his employer, who was
HEY, Mac,
examining several small objects
spread out on the service bench.
"Taking them with me on vacation,"
Mac replied. "Some of the folks in
Florida we visit are sure to say, `Mac,
our electric or electronic what chamacallit isn't working. Wonder if
you'll look at it.' These lights will let me
find anything simple, which is all intend to tackle on vacation. Actually,
it's amazing what a fellow can do with
some simple, rugged, inexpensive test
lights and a little gray matter."
"For instance ?"
"Well, take this Ne -O -Lite Test Light
put out by GC Electronics, a division of
Hydrometals, Inc., Rockford, III. It carries Audiotex catalogue No. 30 -245 or
Calectro No. H3 -452 and sells for just
under a buck. As you can see, it consists of a special two -inch -long, red,
high- impact plastic socket carrying a
neon bulb protected by a tough clear
plastic cone in one end. A current limiting resistor of -I'd guess -about
200,000 ohms is contained in the
socket, and red and black flexible,
sharp -pointed leads come out the bottom. The lamp glows with any voltage
from 90 to 550 volts, ac or dc. The
higher the voltage, the brighter the
glow.
"The neon lamp itself has almost infinite resistance until the contained
gas is ionized by over 90 volts. Until
then, there's no voltage drop across
the series resistor, so the full voltage
across the test leads is applied to the
lamp. Once the gas is ionized by a
voltage in excess of 90 V, current
through the lamp and series resistor is
a function of the voltage across the
leads, but it never exceeds 3 mA, even
with the full 550 volts applied.
"What can you do with it ?"
"A zillion things. If one lead is attached to a spark plug of a running
motor, a bright flash will indicate a
good plug; a dim flash, a fouled plug;
and no flash, a dead plug. Hold on to
I
88
one test lead and probe the two sides
of a 120 -volt outlet receptacle with the
other. When you touch the 'hot' side of
the line, the lamp will glow. If a device
controlled by a wall switch will not
turn on and you don't know if the trouble lies in the device or the switch, turn
the switch on and bridge the test lamp
across the switch terminals. If the
lamp glows, the switch is bad. Do the
same thing to locate a blown fuse.
With a device on the fused line
switched on, check across the fuse
with the lamp. If it glows, the fuse is
open. Alternately, you can check from
the grounded side of the line or the
cabinet of the fuse box to the output
sides of the fuses, one at a time. Failure of the lamp to glow with full 120 -V
brilliance will indicate the bad fuse.
"This little sketch shows how the
test lamp can be used for a continuity
IRON
EXTENSION
CORD
TESTER
indicator. Plug an extension cord into
a wall receptacle and locate the hot
side of the cube tap on the end of the
cord. Plug one lamp lead into this side.
Now plug one prong of the cord of the
device you want to test for continuity
into the other, grounded, side of the
cube tap. Touch the free lamp test lead
to the free prong of the line cord of the
device. A glow of the lamp indicates
continuity.
"The test light will indicate the presence of leakage current. As you know,
one side of the 117 -volt line is
grounded. If there's current leakage
from the hot side of the line to the case
of a device, say a hedge- trimmer, electric drill, refrigerator, dishwasher, etc.,
person touching the device while in
contact with the ground or a grounded
device may receive a severe and
perhaps fatal shock. With a clip lead,
connect one side of the test lamp to a
good ground, such as a water faucet,
and touch the other lead to the case of
the device being tested while the device is operating. Reverse the plug of
the device in the wall socket and test
again. If the lamp glows in either case,
you know there'ssome leakage. It may
not exceed 0.5 mA through 1500 ohms
of noninductive resistance shunted by
0.15 µF, which represents the average
impedance of the human body and the
current is considered permissible for
most devices; but if the lamp glows at
full 120 -V brilliance, you can be suspicious. In all the devices checked at
home, only the electric drill, some fifteen years old, lit the light dimly."
"What's this thing ?" Barney asked,
picking up a small round plastic object
with three prongs on one end to fit a
standard 15 -A, 120 -V grounding receptacle.
"That's a GT -20 'Grounded Outlet'
Tester made by Alco Electronic Proda
I
ucts, 1551 Osgood Street, North Andover, Mass. 01845. It sells, in single
lots, for $7.95 and reveals instantly if a
receptacle into which it is plugged has
current available and is properly and
safely wired. Note the three little round
windows in the end. Two of them,
labelled NEUTRAL and POWER, are
amber, and the bottom one, labelled
DANGER, POLARITY is red. When the
GT -20 is plugged into a grounding receptacle, one or more of the lights behind the windows light if power is
available at the socket. If the socket is
correctly wired, the two amber windows glow. Any other combination of
lights indicates a potentially dangerous receptacle that is improperly
wired or has a broken connection.
"What's inside the thing ?"
"Not being like the little boy who cut
open his drum to find what made the
noise, didn't take it apart to see; but
I'd guess there are three neon lamps
I
with accompanying current -limiting
resistors, each wired between a pair of
prongs. Can you figure out which
lamp is wired between which prongs
to produce the conditions shown in
the little charts ?"
"Child's play!" Barney scoffed.
"Will it work on 2 -hole outlets ?"
"The Code requires that, in all new
construction, only grounding receptacles may be installed. If you replace
a defective receptacle in an existing
POPULAR ELECTRONICS
installation, the new one must be the
grounding type if you can effectively
ground it. If this is difficult or impossible, the receptacle may not be of the
grounding type. You don't want a receptacle with a dummy grounding
orifice that seems to promise but does
not actually provide grounding of a
device with a 3-wire cord plugged into
it. You can use the GT -20 as a 2 -wire
tester by using an adapter plug with
the pigtail fastened to the outlet box
by placing it under ametal screw holding the receptacle plate in place. If the
red light of the GT -20 glows when the
adapter is plugged in, reverse the
position of the two blades. If the red
light still glows, a ground fault is indicated and repairs should be made.
The only fault the GT -20 will not reveal
is switching of the neutral and ground
wires, since both are normally at
ground potential; but this very rarely
occurs.
"How come you've got two neon
test lights ?"
"I haven't. That one you're holding
looks like the H3 -452, but it is really a
Calectro No H3 -454. About the only
difference you can see is that the plastic is blue instead of red. It is called a
Lo -Volt Test Light and will light with 5
to 50 volts ac or dc. If you look closely,
however, you'll see the bulb in the end
is a filament type instead of neon. I've
found this filament will glow dimly
with 3 volts across the test leads while
it is drawing 18 mA. At 12 volts the
filament is a very bright yellow and
draws 45 mA. This goes to 110 mA at
50 volts, and the filament is incandescent white. Filament resistance goes
from 80 ohms cold to 550 ohms at 50
volts, which explains the wide range of
lighting voltage.
"The Lo -Volt Tester is especially
useful in trouble- shooting auto electrical problems. Failure to light across
the battery terminals indicates a dead
battery. If the battery is OK, you can
trace the voltage from it right to an
accessory that fails to work. With the
accessory turned on, the lamp will
light across a defective switch or fuse.
It will also light across a high resistance connection, say a battery cable
connection or starter solenoid contacts, when the starter is actuated and
tries to draw heavy current through
the connection. By connecting the
lamp between an insulation -piercing
darning needle and ground, you can
pinpoint a break in a wire. The lamp
will indicate generator output. It can
be used with the 12 -volt battery to inNOVEMBER 1974
dicate continuity, since it will glow
with any series resistance from 500
ohms down.
"The Lo -Volt Tester is also useful in
the home for checking out low- voltage
door -bell circuits, electric trains, and
slot cars. With a 9 -volt transistor battery, it can be used as a continuity indicator. With a little practice, you can
also use it to indicate the condition of
6- and 9 -volt batteries."
"Well," Barney said as Mac paused,
"that only leaves this little red bulb no
bigger than a match head."
"That's a brand new RLC -400 Battery Status Indicator just released by
Litronix, Inc., 19000 Homestead Road,
Cupertino, Calif. 95014. It sells for a
dollar at Litronix representatives all
over the country. A GaAsP LED and a
voltage- sensing IC are both packed
inside that itty-bitty T -1 lamp package
designed to warn of imminent battery
failure in cameras, tape recorders,
calcualtors, and similar battery powered equipment. The LED lights
brightly at 3 V, glows dimly at 2.5 V,
and is completely dark at 2 V. It draws
about 300 microamperes at 2.5 V, 8 mA
at 3 V, and 20 mA at 4 V. Five volts,
forward or reverse, is maximum.
"To use the RLC -400 with higher
voltage batteries presented a bit of a
problem. A series resistor subjected
the device to a high turn -on voltage
and separated on on -off points too
much. A zener took care of the first
problem, but the on -off points were
only a half -volt apart. finally worked
out the circuit shown to let me use the
RLC- 400
I
6.8V
X
47011
+
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ZENER
I2V
-9V
YRLC-400 with any battery voltage and
make the on -off span proportional to
that voltage. With the values shown, 3
V appears across the LED with 12 V
across points X and Y. There is 2.5 V
across the LED with 9 V at X -Y. Other
zeners and resistor values can accommodate other battery voltages
and provide any desired span between
new and discard battery voltage. This
little lamp has a lot of exciting possibilities," he concluded.
"You know," Barney mused, "a
knowledgeable guy can do a lot with
comparatively simple equipment."
"Build -it-Yourself" and save
up to 50% with our famous
electronic kits.
For latest EICO Catalcg on Test
Instruments, Automotive and Hobby
Electronics, Eicocraft Project kits,
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of nearest EICO Distributor, check reader
service cart or send 500. for fast first
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EICO -283 Malta Street,
Brooklyn, N.Y. 11207
Leadership in creative electronics
.since 1945.
CIRCLE NO.
114
ON READERS SERVICE CARD
89
i Solid State
By Lou Garner
USEFUL CIRCUITS FOR FIELD EFFECT TRANSISTORS
THOUGH more versatile than bipolar types, except in
some power applications, field effect transistors
-FET's -have never been overly popular with experimenters and hobbyists. True, FET's have been featured in
magazine construction articles from time to time, and
there have even been several.project booklets published
featuring FET circuits but, somehow, these devices have
never really "caught on."
There are probably several reasons for the FET's lack of
popularity. One may be the paucity of application data
compared to what is available on bipolar devices. Another
reason, perhaps equally important, may be the somewhat
confusing situation regarding types. FET's are manufactured in two general categories and six major subcategories, in addition to variations relating to electrical
specifications. The two broad categories are insulated
gate types, or IGFET's, and junction types, orJFET's. Since
many insulated gate FET's are manufactured using MOS
technology, these are often designated MOS- FET's, while
junction FET's frequently are identified simply as FET's
(without the J prefix). But there's more. IGFET's may be
manufactured for use in either depletion or enhancement
modes, each of which has its own technical advantages,
but which may require somewhat different application
techniques, depending on the circuit in which it is used.
Finally, both IGFET's and junction FET's are available as
either n- channel or p- channel devices. These are analogous to npn and pnp bipolar transistors, in that they may be
used in similar applications, but require opposite dc
polarities.
Poor availability may be another reason for the FET's
lack of popularity. The first low -cost experimenter's transistor, the famous Raytheon CK722, was a bipolar device.
FET's, on the other hand, were comparatively late arriving
on the scene and, by the time inexpensive FET's were
available, a mass of application literature and project articles had been published featuring bipolar devices, resulting in a much larger demand by users for these types. As a
result, suppliers offering general -purpose semiconductor
devices today may list scores of different bipolar transistors but maybe only from one to a half -dozen FET's. As of
the present writing, for example, there are only five different FET's listed in Sylvania's ECG line, two types in RCA's
SK line, eight in Motorola's HEP line, three in GC
Electronic's Calectro line, and one in Radio Shack's
Archer line. There are many other types of FET's in production of course, but the prospective user will not find these
in a general line on a self- service sales rack. Instead, he'll
have to buy them across the counter, specifying
manufacturer's name and type number, and perhaps even
seek out a broad line or industrial electronics distributor
90
stocking the units needed. In extreme cases, the user may
find it necessary to order specific devices from a large
mail -order or semiconductor specialty house.
The FET has been called the "semiconductor equivalent
of the vacuum tube." This analogy is pretty close to the
truth. The FET offers high input and output impedances. It
is a voltage, rather than a current, amplifier. It can be
self- biased via a source resistor and its characteristics
curves are quite similar to those of a pentode vacuum tube.
The basic FET has three terminals -gate (G), source (S)
and drain (D). These correspond, generally, to the base,
emitter and collector of a bipolar transistor, or to the grid,
cathode and plate of a vacuum tube, respectively.
The IGFET (or MOSFET) has an extremely high input
impedance. The junction FET also has a high input impedance, although not nearly as great as the IGFET; but, from
an experimenter's viewpoint, it is by far the easier device to
use in practical circuits. Except for those types with internal protection, the IGFET (MOSFET) requires special
treatment. It is particularly susceptible to damage from
static charges or transient voltages applied to its gate
electrode, even during the simple processes of handling
and installation. Some types, in fact, are supplied wrapped
in metal foil or with their leads shorted by a metal eyelet or
spring to prevent accidental damage. The short can be
removed safely only after the device is installed in its circuit.
Perhaps the best way to become familiar with the FET is
to try the device in a few practical projects. Several useful
and easily constructed junction FET circuits are illustrated
in Figs. 1 and 2. These were adapted from a FET applications bulletin published several years ago by Siliconix, Inc.
1. Useful FET circuits: (A)
Crystal oscillator; (B) Tone control.
Fig.
BASS
R2
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R4
500K
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WATTEN.
TREBLE
NOTE: ALL CAPACITORS ARE IN yF
(A)
(B)
v+
POPULAR ELECTRONICS
(2201 Laurelwood Road, Santa Clara, CA 95054). In each
circuit, resistors are rated for 1/4 or 1/2 watt, while the
capacitors may be ceramic, mica, plastic or tubular paper
types, except where a dc polarity is shown, in which case
an electrolytic should be used. Capacitor working voltages
should be chosen on the basis of the dc supply voltage
used, of course, with 50 -volt, or better, units adequate for
all four circuits. Although p- channel devices are indicated,
comparable n- channel FET's may be substituted in each
design if dc polarities are reversed and if bias and supply
voltages are readjusted for optimum performance.
Suitable for use as the first stage of a transmitter, as a
marker generator, and in similar applications, the FET
crystal -controlled oscillator shown in Fig. 1A requires relatively few components. The original design specified a type
2N2608 for Q1, a -MHz crystal, and a 22 -volt dc power
supply. It may be assembled on a perf board, etched circuit
board, or even on a small chassis using point -to-point
wiring techniques.
In operation, the drain -gate feedback needed to start
and sustain oscillation is provided by stray interelectrode
and wiring capacities. Gate bias is established by source
resistor R2, shunted by bypass capacitor C2. Drain tuning
is provided by adjustable inductance L1, shunted by Cl.
The L and C values specified are for -MHz operation but
these may be changed, of course, for other frequencies.
Featuring separate treble and bass controls, the tone control circuit illustrated in Fig. 1B may be used with virtually any audio amplifier-phonographs, tape recorders or
playbacks, or PA systems. Depending on application, it can
be assembled as a separate control or incorporated as part
of more complete amplifiers. Except for the treble control,
R4, standard components are used throughout the design.
As in the previous circuit, a 22-volt dc power supply should
V-
R3
R6
4.7K
2.2K
01
C11.05NF
02
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C2
R4
R5
250K
250K
IN
OUT
4
R2
R7
2.2K
4.7K
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(A)
V
1
R5
25K
R2
2.2 MEG
C2
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220K
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R3
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NOVEMBER 1974
V+
Fig. 2. Phase shifter (A) and
automatic gain control (B).
New
o
CI
°The
'
,ALL /EO
ELECTRON /ES
In
0° to 180`.
+
(B)
be used, and Q1 is specified as type 2N2843.
operation, Q1 serves as a conventional common source amplifier, with gate bias provided by source resistor R8, bypassed by C5. Resistor R7 serves as the drain
load and C1 and C6 as the input and output coupling
capacitors, respectively. A variable frequency response
characteristic is achieved by a combination of attenuation
and negative feedback techniques. When bass control R2
is shifted toward its BOOST position, it serves as a shunt
across C2, increasing the amplitude of the bass portion of
the applied signal. When R2 is set toward its ATTEN position, its shunting effect across C2 is reduced and, at the
same time, a negative feedback signal coupled back from
the drain through R6 serves to reduce effective stage gain
at the lower frequencies. A similar technique is used for the
treble control. With treble control R4 in its maximum boost
position, C4 serves as a high- frequency shunt across the
bass control network. With R4 set for maximum attenuation, high- frequency negative feedback from Q1's drain is
applied through C4 to the gate electrode, effectively reducing stage gain.
You can use the phase shifter circuit shown in Fig. 2A in
test instruments, such as oscilloscopes, in demonstration
projects, and in musical synthesizers. It requires a 12 -volt
dc supply when 2N2609 FET's are used for Q1 and Q2.
In operation, Q1 and Q2 are used as cascaded split -load
amplifiers, with R3 and R6 serving as the drain loads and
R2 and R7 as the source loads, respectively. Networks
C1 -R4 and C2 -R5 provide a control over the signal phase
shifts, with each stage supplying a controllable shift from
i
1111
.
Allied,lock,
=Rent
;
n
2..
I'
mtNI,
4
T
1975
Engineering MI
:'
s,
7
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Manual & Iiii
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Purchasing
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iI9ß EXGIXFF.MIXUUA[XüXGG.XaISO
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A "must" for
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There is only one way to a career in
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50 years CREI programs have been
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CAPITOL
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Accredited Member, National Home Study Council
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FOUR CHANNEL DIGITAL
HANDHELD MEMORY SCOPE
MS -416 is a valuable tool for circuit analysis:
N.
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tors
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stereo receivers - electronic calculadigital clocks - digital auto electronics
and more. The MITS MS416- digital pocket
scope is a tour -channel, digital logic
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The clock time -base
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The
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SIZE: 5zá" x v<" z uh"
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SPECIAL OFFER
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NAME
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CITY
STATE & ZIP
Minn / 6328 Linn, N.E., Albuquerque, New Mexico 87108 505/265 -7553 Telex #660401
a
L
CIRCLE NO. 27 ON READERS SERVICE CARD
There are probably many uses you can devise for the
audio automatic gain control (agc) circuit illustrated in Fig.
2B. Use it to maintain a constant level in a tape recorder, to
prevent overmodulation in a transmitter, or as part of an
expander or compressor. According to Siliconix, the circuit will provide an effective agc range of 60 dB and has a
frequency response flat to within 1 dB from 1.0 Hz to better
than 10 kHz. Type U112 devices are specified for both Q1
and Q2, with a 12-volt dc power supply.
In operation, Q1 serves as a variable resistance, Q2 both
as a gate bias control for Q1 and as a source -follower
amplifier. Series resistor R1 and Q1's source -drain resistance, shunted by R2, form a simple voltage divider. FET
Q1's source -drain resistance, in turn, is determined by its
gate bias, which is established by Q2's drain current and
the agc voltage applied to Q2's gate. As increasing agc
voltage is applied, Q2's drain current is reduced, increasing Q1's negative gate bias and thus reducing Q1's effective source -drain resistance, thus reducing the effective
level of the input signal applied through C2 to Q2's gate
and, therefore, the output signal developed across Q2's
source load, R4. As the agc voltage is reduced, the opposite action takes place, increasing the output signal level.
Although the parameters of the agc circuit are not critical, one simple adjustment is required for optimum performance. With the circuit wiring completed and checked,
apply the dc supply voltage, a small input signal, and zero
agc voltage. Adjust drain load R5 for a maximum output
signal across source load R4.
If you've been intrigued by our discussion of the versatile
FET and would like to explore the subject in greater detail,
we can recommend any (or all) of the following books:
An Introduction to Field Effect Transistors, by J. Watson,
published by Siliconix, Inc.
FET Circuits and abc's of FET's, both by Rufus P. Turner,
published by Howard W. Sams & Co., Inc.
Field Effect Transistor Projects, published by Motorola,
Inc., Semiconductor Products Division, and offered
through HEP distributors.
Reader's Circuit. Featuring
Put more
a popular IC op amp and a
pair of zener diodes, the portable scope calibrator circuit
given in Fig. 3 was submitted by reader Ted Reiter (1442
Brook Drive, Titusville, FL 32780). Layout and lead dress
are not critical and the project can be duplicated quite
easily in a single evening or on a weekend by the average
hobbyist.
In this circuit, ICI serves as a simple relaxation oscillator, supplying an output signal which is clipped by zener
diodes D1 and D2 in conjunction with series resistor R4,
Fig. 3. Reader's circuit for
portable scope calibrator.
punch in your work.
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CIRCLE NO 19 ON READERS SERVICE CARD
POPULAR ELECTRONICS
e
1975
LAFAYETTE
RADIO ELECTRONICS
CATAL
If you're interested in electronics you NEED
is catalog! Completely re- designed for easierhan -ever ordering, with the newest and )est
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97
developing a fixed -level square -wave
output signal with a peak -to -peak amplitude equal to the total zener voltage. Operating power is supplied by
batteries B1 and 82 controlled by a
dpst switch, Si.
Readily available standard components are used in the design. Ted
chose a type 741 op amp for ICI. The
terminal numbers shown are for the
"minidip" version used in his original
model. The resistors may be either 1/4
or 1/2 watt, while Cl is a low-voltage
ATTENTION
HOBBYISTS!
BUILD THIS
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Everything needed to build a complete decade
counter 09) including a printed circuit board.
Operates from a 5 Volt D.C. supply. Can be
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your nearby CALECTRO
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ceramic capacitor. Batteries 81 and
82 are conventional 9 -volt transistor
units, with Si a toggle, slide or rotary
switch. Ideally, the zener diodes
should be matched, with a total voltage of 10 volts. Unable to obtain a
perfect match, Ted assembled his
model using a 5.6 -volt zener for D1, a
4.5 volt device for D2, providing a
nominal 10.1 -volt output signal. The
actual output voltage, of course, will
depend on the zener diode voltage
tolerances.
If a particular application requires
an accurately known output voltage, a
simple test will establish this value.
Disconnect R4's upper lead (pin 6,
ICi). Reverse D2. Connect R4's free
lead to the positive terminal of a
15 -18 -volt dc source, negative to circuit ground. Finally, measure the do
voltage across the series zeners using
an accurate voltmeter. Restore the
circuit to its original condition for
normal operation.
Device/Product News. We've received a number of inquiries from
readers asking what LED's have the
lowest current ratings. Actually, most
LED's will operate at currents much
lower than their maximum ratings,
and we've obtained satisfactory light
outputs with levels as low as 8 to 10
mA using commercial 50 -mA (max)
devices. However, the results are not
consistent. One LED of a given type
may provide a good output at a 7 -mA
level, while another of the same type
may require 10 mA, and still another 12
or 15 mA. At least one firm, however,
Data Display Products (5428 W. 104th
St., Los Angeles, CA 90045), offers
complete LED panel -light assemblies
designed to be used at a mere 5-mA
current level. Available colors are
green, yellow, amber and red, at voltages from 1.8 to 28 V. Single unit
prices range from $1.58 for a 1.8 -volt
device (requiring an external current
limiting resistor) to $1.76 for a 28 -volt
type (with built -in resistor). Each unit
is supplied with a mounting clip and
Neoprene washer.
You can add another name to the
roster of firms manufacturing dual
555 -type timer IC's: Silicon General,
Inc. (2712 McGaw Ave., Irvine, CA
92705). Packaged in 14 -pin DIPs, the
Silicon General version is identified as
the SG556/SG556C.
Perhaps a dual timer is not enough
for your application. If this is the case,
you might check the new quad timers
now available from Signetics (811 E.
Arques Ave., Sunnyvale, CA 94048).
Identified as Models 553 and 554, the
new units are supplied in a 16 -pin DIP.
The 553 and 554 are not exact duplicates of the industry standard, the
familiar 555, however. They have no
reset control line and a common control voltage pin is provided for all four
timers in the package. Basically similar in application, the 553 is rated to
sink 100 mA, the 554 to source an
equivalent current, compared to the
200 mA ratings of the 555/556 types.
Another interesting difference between the 553/554 devices and the
555/556 types is a simplification of
their timing equations, from T = 1.1 RC
to T = RC for the new units.
How many watts in a dollar? If this
seems like a silly question, comparable to a mixing of apples and oranges,
it is, however, the type of question that
a transmitter designer must ask himself. According to Motorola, its new
MRF621 uhf power transistor can deliver an output signal in the 406 -to512 -MHz band for less than a dollar
per watt. Designed for 12.5 -V dc operation, the new device can deliver 45 W
at 470 MHz with a minimum power
gain of 4.8 dB and collector efficiency of 55 %. Featuring an internal MOS
capacitor chip for "controlled -Q"
operation, the MRF621 sells for
$39.00 each in unit quantities, even
less if you want to buy 25 or more at
a time.
RCA's Solid State Division (Box
3200, Somerville, N.J. 08876) has introduced a new linear IC and added
another COS /MOS device to its ex-
panding
line.
Designated type
CA3127E, the new linear device con-
sists of
5
independent general -
purpose silicon npn transistors constructed on a common monolithic
substrate to provide close electrical
and thermal matching. Suitable for
low -power applications at frequencies
up to 500 MHz, the CA3127E, supplied
in a 16-lead plastic DIP, can be used in
vhf amplifiers, mixers and oscillators,
in -f converters and amplifiers, and in
sense amplifiers, synthesizers, and
cascade amplifiers. RCA's latest
COS /MOS device, identified as the
CD4093AE, is a quad 2 -input NAND
gate consisting of four identical
Schmitt trigger circuits, each of which
functions as a two -input NAND gate.
The CD4093AE, packaged in a 14 -pin
plastic DIP, is suitable for use in
wave -shapers and pulse- shapers, monostable and astable multivibrators,
and NAND functional logic circuits. Q
i
POPULAR ELECTRONICS
ELECTRONICS MARKET PLACE
NON -DISPLAY CLASSIFIED: COMMERCIAL RATE: For firms or individuals offering commercial products or services, $1.60 per word (including name and
address). Minimum order $16.00. Payment must accompany copy except when ads are placed by accredited advertising agencies. Frequency discount; 5% for 6
months; 10% for 12 months paid in advance. READER RATE: For individuals with a personal item to buy or sell, $1.00 per word (including name and address.)
No minimum! Payment must accompany copy. DISPLAY CLASSIFIED: 1" by 1 column (2 -1/4" wide), $200.00. 2" by 1 column, $400.00. 3" by 1 column, $600.00.
Advertiser to supply cuts. For frequency rates, please inquire.
GENERAL INFORMATION: First word in all ads set in bold caps at no extra charge. All copy subject to publisher's approval. All advertisers using Post Office
Boxes in their addresses MUST supply publisher with permanent address and telephone number before ad can be run. Advertisements will not be published
which advertise or promote the use of devices for the surreptitious interception of communications. Closing Date: 1st of the 2nd month preceding cover date
(for example, March issue closes January 1st. Send order and remittance to POPULAR ELECTRONICS, One Park Avenue, New York, New York 10016,
Attention: Hal Cymes.
COMPLETE CONSTRUCTION PLANS- TELEPHONE: Answering Device, Automatic Dialer, "Black Boxes ". Call
Diverter, Call Limiter. Conference Bridge, Central Dial
Exchange, Melodic Ringing, Recorder -Actuator, Remote
FOR SALE
Fiber optics. LED's. transistors,
diodes, rectifiers, SCR's, triacs. parts. Poly Paks, Box 942,
Lynnfield, Mass. 01940.
FREE! bargain catalog.
GOVERNMENT Surplus Receivers. Transmitters,
Snooperscopes, Radios, Parts, Picture Catalog 25 cents.
Meshna, Nahant, Mass. 01908.
LOWEST Prices Electronic Parts. Confidential Catalog
Free. KNAPP, 3174 8th Ave. S.W., Largo, Fla. 33540.
ELECTRONIC PARTS, semiconductors, kits. FREE FLYER.
Large catalog $1.00 deposit. BIGELOW ELECTRONICS,
Bluffton, Ohio 45817.
RADIO -T.V. Tubes -36 cents each. Send for free catalog.
Cornell, 4213 University. San Diego, Calif. 92105.
AMATEUR SCIENTISTS, Electronics Experimenters.
Construction plans -Complete.
Science Fair Students
including drawings, schematics, parts list with prices and
Lasers Psychedelic shows
Robot Man
sources
EmotionlLie Detector - Touch Tone Dial
Quadraphonic Adapter - Transistorized Ignition
- Sound Meter over items. Send
Control. Schematics, Speakerphone. Telelink Burglar
Alarm, Voice Scrambler. $3.00 each. ELECTRONIC:
Biofeedback Conditioner. Horticulture Stimulator,
Mu Itifrequency Encoder Network (Speeds telephone
calling 100 %!), $5.00 each. DODECAHEDRON Speaker
Enclosure $7.50. Photographic Pinhole Camera $2.00. ONE
YEAR SUBSCRIPTION: Telephone -Electronics Newsline
$3.00. COURSES: Telecommunications, Electronic
Protective Systems, F. E. T. Theory and Application, $24.95
each. Catalog of plans 50 cents. All of the construction
plans above. $19.95. TELETRONICS COMPANY OF
AMERICA. P.O. Box 3486, Los Angeles. California 90028.
JUSA.
B
25
60
Burglar Alarm
cents coin (no stamps) for complete catalog. Technical
Writers Group, Box 5994, University Station, Raleigh, N.C.
AUTHENTIC, INSTRUMENTED, FLYING ROCKETS for
casual or serious experimenters. Over 80 scale original,
Test Equipment
RAYTHEON, ICC /MULLARD Tubes
TELEMATIC Test Jigs
-
DISCOUNT PRICES
& K, SENCORE, LEADER and RCA
multi -stage or ready -to -fly models. Solid- propellant
engines for safe, electric launch system liftoffs up to 2,500
feet. Measure altitude, temp. inversions, more. Real
telemetry, electronic tracking, aerial still and movie photography with super- miniaturized equipment. New, detailed
tech manual and full -color catalog. 25 cents from ESTES
Free Catalog
FORDHAM RADIO SUPPLY CO., INC.
04 558 Morris Ave.
Bronx, N.Y. 10451
27607.
METERS -Surplus. new, used, panel or portable. Send for
list. Hanchett, Box 5577, Riverside, CA 92507.
WE
SELL
CONSTRUCTION
TELEPHONE:
PLANS.
alarm supplies and information. Free
catalog. Protecto Alarm Sales, Box 357 -G, Birch Run,
Michigan 48415.
BURGLAR -FIRE
INDUSTRIES Dept. 18B, Penrose, Colo. 81240.
ELECTRONIC Parts wholesale. Catalog 10 cents. Donlyn
Electronics, P.O. Box 15421, Phoenix, Arizona 85060.
Answering Machine, Speakerphone, Carphone,
Phonevision. Auto Dialer, Touch Button Dialer, Central
Dial System. TELEVISION: $35.00 Color Converter. Video
Tape Recorder. $25.00 Camera. HOBBYIST: Electron
Microscope, 96 Hour Tape Music System. Ultrasonic Dishwasher, Radar-Oven, Plans $4.95 each. NEW ITEM: $75.
Electronic Pocket Calculator, $7.50. COURSES: Telephone
Engineering $39.50. Detective Electronics $22.50,
Integrated Circuit Engineering. $49.50. NEW SUPER
HOBBY CATALOG plus year's subscription to Electronic
New Letter AIRMAILED $1.00. Don Britton Enterprises.
6200 Wilshire Blvd., Los Angeles, Calif. 90048.
JAPAN HONG KONG DIRECTORY. World products
information, $1.00 today. World Trade Inquiries, Hillyard,
Washington 99207.
FREE CATALOG. IC's, Puts, Transducers, Thermocouples,
Led's, Transistors. Circuit Boards, parts. Chaney's, Box
15431, Lakewood, Colo. 80215.
WAVEFORM GENERATOR KIT 8038 Function Generator
IC Producing Sine, Square, Triangular Waveforms, $10.95
PPD. 8038 IC, $6.75 each PPD. PHOTOLUME
CORPORATION, 118 East 28th Street. New York. NY 10016.
LOOKING FOR A NEW CHALLENGE?
... than balk, a TV camera!
ONLY SOLIO.STATE CAMERA AVAILABLE IN KIT FORM
OR FACTORY ASSEMBLED. COMPLETE KIT WITH VIDI.
CON TUBE ONLY 5166.00 POSTPAID DELIVERY ANY.
MEXICO. OPTIONAL
WHERE IN U.S.A., CANADA
d
AU010 SUSCARRIER RINDS. WRITE or PHONE NOW
FOR COMPLETE CATALOG OF KITS, PARTS .nd PLANS.
DIN 402 -987 -3771.
1301
ATV Research
MFOADWAY
DAKOTA CITY, NEAR.
68731
DIGITAL ELECTRONICS: Complete schematics, parts
Discrete Component Digital Clock,
lists, theories
Sound Sensitive Switch, $1.50. Increase technical
$3.00
Complete Course In Digital
competence, hobby skills
Electronics is highly effective, $10.00. Free literature.
DYNASIGN, Box 60A7, Wayland, Mass. 01778.
MECHANICAL, ELECTRONIC devices catalog 10 cents.
Lowest Prices. Fertik's, 5249 "D ".
Greatest Values
-
-
-
-
Philadelphia, Pa. 19120.
SOUND SYNTHESIZER KITS -Surf $12.95, Wind $12.95,
Wind Chimes $17.95, Electronic Songbird $6.95, Musical
Accessories, many more. Catalog free. PAIA Electronics,
Box J14359, Oklahoma City, OK 73114.
Parts, circuit boards for POPULAR
ELECTRONICS projects. PAIA Electronics, Box C14359,
Oklahoma City, OK 73114.
FREE CATALOG.
INTERNATIONAL ELECTRONICS UNLIMITED
7400
7401
7402
TTL
$ .19
7474
7475
.19
1111r
$ .43
.75
.47
7476
7403
7404
7405
7406
7407
7408
7409
7410
7413
7415
7416
.19
.19
.22
.22
.39
.39
.25
.25
.19
.79
.39
.39
7492
7493
7494
7495
7496
74107
.79
7417
.39
74121
.57
7420
7423
7425
7426
7427
7430
7432
7437
7438
7440
.19
.35
.39
.29
.35
.22
.29
.46
.39
.19
74123
74125
74126
74141
74145
74150
74151
74153
74154
74157
.99
.69
.79
1.23
1.15
1.09
.89
1.29
1.59
1.29
7441
1.09
74161
7442
7443
7444
7445
7446
.99
.99
1.10
74163
74164
74165
74166
74173
74177
1.39
1.59
1.89
1.89
1.65
1.65
.99
3.65
7447
7448
7450
7453
7454
7460
7464
7465
7472
7473
1.10
1.15
1.15
1.15
.24
.27
.39
.19
.39
.39
.36
.43
7483
7486
7489
7490
1.11
7491
1.29
74181
74181
74182
74190
74193
74194
74195
74198
74199
.44
2.75
.76
.79
.89
.89
.89
.49
301
Hi pert. op amp
307
308
309K
Op amp
311
319
324
339
340T
380
381
550
555
560
565
709
723
741
747
748
3900
SUPPLIED ON REQUEST
WITH ORDER. ADD $.50 PER DATA
FOR ITEMS PRICED UNDER 51.00
12V, 15V, 18V, 24V) 10-220
2w audio amp
DIP
mDIP
1.95
1.49
.89
1.79
.79
.99
2.75
2.65
.29
.35
.35
.79
.39
.69
.65
.65
5.95
.39
.39
.39
.79
.89
Lo noise dual preamp DIP
Prec. V reg
Timer
Phase locked loop
locked loop
Op amp
Com reg.
Dump.
amp
741
Dua1741
Frog adj 741
Qual Comp op amp
Quad ime
Phase
DIP
mDIP
DIP
DIP
DIP
DIP
DIP
mDIP
DIP
DIP
DIP
DIP
mDIP
mDIP
mDIP
DIP
DIP
Ten nano /sec capability
Checks TTL & DTL logic
g
Dual slope memory
Internal 5V regulator
with all necessary compoKit is complete
d
instructions
vents, case, probe, complete
a
$19.95
and logic chart
KIT
U
POWER SUPPLY SPUTTER
Ground reference for positive & negative
output from single supply any DC
source to 20V
-
Balanced output adjustment
1 amp -current capability with sink
Increase usefulness of your power supply
Complete with all components &
$4 95
instructions
I
Il
1101
1103
5260
7489
8223
ON REQUEST
WITH ORDER. ADD $.50PER DATA
FOR ITEMS PRICED UNDER $1.00
CALCULATOR & CLOCK CHIPS w /data
5001 LSI
5002 LSI
5005 LSI
MM 5311
IlMM 5312
MM 5313
MM 5314
40 pin DIP 4 funct
$ 3.95
Same as 5001 exc batt pwr
28 pin DIP 4 funct w /mem
8.95
8.45
9.95
pin BCD 6 dig mus
pin 1 pps BCD 4 dig mus 6.95
pin 1 pps BCD 6 dig etas 7.95
8.95
pin 6 dig max
12.95
MM 531640 pin alarm 6 dig
4000 SERIES RCA-EQUIV.
2.95
1.35
2.75
.55
.55
1.35
2.85
763
5V reg 1A
Hi part. V comp
mDIP
DIP
Hiapeed dual comp
DIP
Quad op amp
DIP
Quad comp
Pos V reg (5V, 6V, 8V,
3900
3905 Prec. timer
8038 Function gen.
75451 Dual prl. driver
75452 Dual prl. driver
75453 Dual prl. driver
75491 Quad seq driver
75492 Hex dig. driver
DATA SUPPLIED
.89
1.59
1.39
1.39
.99
2.19
2.19
Micro-pwr op amp
'
28
24
28
24
e...nnuuKu
I
-
14061659 -4773
L
MEMORIES
256 bit RAM MOS
1024 bit RAM MOS
1024 bit RAM low power
64 bit RAM TTL
Programmable ROM
$1.75
4.95
3.95
2.75
4.95
LED'S AND OPTO ISOLATORS
$ .25 ea.
MV106 Red TO 18
.20
MV50
Axial leads
.33
MV5020 Jumbo visible red
.60
ME4
Infra red ditf. dome
2.50
MANI
Red 7 seg..270"
4.95
Red alpha num .32"
MAN2
.79
MAN3A Red 7 seg..127"
MAN3M Red 7 see..127" claw 1.15
90"
2.15
MAN4
Red 7
2.95
MANS
Green 7 seg..270"
1.35
MAN7
Red 7 seg..270"
3.95
MAN8
7 seg. .270"
4.65
MAN66 60" high dir. view
2.15
DL707 Red 7 mg..3"
1.09
MCD2
Opto -iso diodes
.69
Opto -iso transistor
MCT2
ON ORDERS OVER $25.00 DEDUCT 10%
All items are new, unused surplus parts - tested functional.
Satisfaction is guaranteed. Shipment will be made via first class
mail - postage paid - in U.S., Canada and Mexico within three
$5.00. California
days from receipt of order. Minimum order
-
residents add sales tax.
INTERNATIONAL ELECTRONICS UNLIMITED
P.O. BOX 1708
MONTEREY, CALIF. 93940 USA
CIRCLE NO. 21 ON READERS SERVICE CARD
NOVEMBER 1974
4
LOGIC PROBE KIT
$ .32
.35
1.10
1.65
1.05
1.29
1.95
1.09
mDIP
mDIP
mDIP
3808 .6w audio amp
3 .89
DATA
CD4001 $ .55 CD4017
CD4009
.85 CD4019
CD4010
.85 CD4022
CD4011
.55 CD4023
CD4012
.55 004025
CD4013
1.20 CD4027
CD4016
1.25 CD4035
LINEAR CIRCUITS
99
DIP SOLDER TAIL SOCKETS
DUAL IN -LINE SOLDER TAIL SOCKETS
GOLD CONTACTS
.74
28 PIN
1.30
22 PIN
1.00
36 PIN
1.55
24 PIN
1.05
40 PIN
1.75
.
Also available - wire wrap sockets - 1/2/3 levels write or call for
large volumn DISCOUNTS
....44
....52
....54
8 PIN
14 PIN
16 PIN
18 PIN
T T
7400 $ .18
...
...
...
...
.
.
L
74157 $1.55
74160 1.65
7407
.50
7453 $ .27
7454
.40
7459
.25
7460
.25
7470
.45
7472
.41
7473
.47
7474
.47
74170
3.00
7408
.25
7475
.90
74173
7409
7410
7411
.25
.23
.30
7476
7480
7482
74174
74175
1.75
1.85
1.85
74176
.85
7413
.89
7483
74177
7416
7417
7418
.45
.45
.25
.23
.27
.32
.27
7485
7486
7488
7489
7490
7491
7492
7493
7494
7495
7496
.47
.50
1.75
1.15
1.10
.47
.85
1.05
3.75
4.00
3.00
.89
74182
74184
74185
74187
74190
74191
74192
7401
7402
7403
.23
.23
.23
.25
.24
7404
7405
7406
.50
7420
7421
7423
7425
7426
7427
7429
7430
7432
7437
7438
7439
7440
.31
7442
7443
7444
7445
7446
7447
7448
7450
.32
.40
.33
.26
.45
.50
.50
.23
1.10
1.05
1.10
1.15
1.10
1.25
1.25
1.25
.25
7451
.27
7441
.97
74107
74121
74122
74123
74125
74126
74141
74145
74150
.95
74151
74153
1.20
1.50
1.25
74154
74155
74156
1.30
1.30
74163
74164
74165
74166
2.50
2.50
2.50
1.75
74181
.95
.95
74100
1.65
74180
1.15
.95
.95
1.50
.47
.55
.47
1.05
.60
.80
1.15
1.15
74161
1.00
2.30
2.30
7.00
1.50
1.50
74197
1.50
1.50
1.50
1.05
1.25
1.05
74198
74199
74200
2.25
2.75
7.00
74193
74194
74195
74196
PROJECTS
8263 Sig. 7.00
8267
4.00
2513
14.00
2518
7.00
2424
7.00
2425
7.00
4024
2.25
20% Discount for 150 Pieces Combined
No
.
CMOS
CD4001 $
.55
CD4002
CD4009
CD4010
.55
1.40
.55
.55
1.50
1.40
.55
.55
1.25
.60
.45
.70
.65
2.60
8000 Series
8090
$ .35
8091
-8098
.55
8223
5.00
8280
.75
8288
1.15
8880
1.35
Many Other
8000 Series
LEDS
MV 10
MV 50
MV 5024
MAN -1
MAN -3
MAN -4
MAN -7
DL 33
5/1
6/1
5/1
1.95
.95
1.95
1.50
1.95
- Above 7400 Series
sk$PECIAL$0-a
.
IN4148 Silicon Signal Switching Diode
TIS97 - TIS98 NPN Transistor
7400 -7401.7403 GATES
7404 -7410.7420 GATES
LM301H /LM301N OP. AMP.
5 V 1 AMP
LM309K
LM311 H; LM311 N Comparators
2 Watt Audio AMP
LM380N
Quad AMP DIP
LM3900N
Precision Timer
LM3905N
LM741CH /LM741CN OP. AMP.
MM5314
24 Pin Digital Clock Chip
MM5316
40 Pin Alarm Clock Chip
MM5016H
MM1103
2519
2529
15/1.00
10/1.00
6/1.00
5/1.00
3/1.00
1.25
1.00
1.25
.55
.65
3/1.00
512 Bit Dynamic Shift Reg.
1024 X 1 Bit Dynamic RAM
40 X 6 Static Shift Register
240 X 2 Static Shift Register
7.95
11.95
2.00
3.95
4.00
5.00
LINEAR
LM300
Pos. V Reg
LM301 H/N
Improved Op Amp
LM302H
LM304H
LM305H
LM307H /N
LM308H /N
LM309K
Voltage Follower
LM31OH
LM311 H/N
To 5
$ .85
.40
Negative Voltage Regulator
Positive Voltage Regulator
Op Amp (Super 741)
Micro Power Op Amp
Volt Regulator / Amp
Improved Volt. Follwer Op Amp
Hi-performance Volt. Comp.
5
.85
1.10
1.00
.40
1.15
1.70
1.35
1.15
LM319H
Hi-Speed Dual Comp.
1.55
LM32OK- 5V -15V To 3 Neg. Regulator
1.75
LM324N
Quad 741 Op Amp
1.90
LM339
Quad Comparator
2.35
LM34OK-5V- 12V- 15V-24
Positive Volt Regulator
2.00
LM370N
A 6 C - Squelch Amp.
1.55
LM373N
AM /FM $$ B Strip
3.30
LM38ON
2 Watt Audio Power Amp
1.50
LM703H
RF /IF Amp
45
1.00
LM5558V
Dual Op Amp
LM741H /N
Comp. Op Amp
.40
LM747H /N
Dual Compen. Op Amp
.90
LM748N
Freq. Adj. 741
.40
LM1458N
Dual Comp. Op Amp
.65
LM3065N
T.V.-FM Sound System
.75
LM3900N
Quad Amp
.65
LM555N
Timer
1.00
LM565- LM566 -LM567 Phase Looked Loops
2.50ea
LM 7522
Core Memory Sense Amp.
2.50
LM 7524
Core Memory Sense Amp.
1.50
LM 7535
Core Memory Sense Amp.
LM75451
Dual Peripheral Driver
1.49
LM75452
Dual Peripheral Driver
.49
LM75453
Dual (LM3511
Satisfaction Guaranteed. All Items 100% Tested
$5.00 Min. Order
1st Class Mail
No Extra Charge
California Residents
Add 6% Sales Tax
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-
Wholesale Outlets
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CONSTRUCTION
MANUALS! -Reclaim refined GOLD and SILVER for
EXCELLENT full time or part time money! -Color Catalog
25 cents -Airmailed 50 cents. Creative Products, Dept. PE1174, 8415 Lofland, Houston, Texas 77055.
BUGGED ? ?? New locator finds them fast. Write, Clifton,
11500 -L N.W. 7th Avenue, Miami, Florida 33168.
TELEPHONE "BUGGED "? Countermeasures Brochure
$1.00, Negeye, Drawer 547, Pennsboro, W. VA 26415.
.60
CD4011
CD4012
CD4013
CD4016
CD4023
C04025
CD4027
CD4030
74C00
74C04
74C20
74C173
WE
Data Sheets .2011 each
HEAR POLICE /FIRE Dispatchers! Catalog shows exclusive
directories of "confidential" channels, receivers. Send 10
cent stamp. Communications, Box 56 -PE, Commack, N.Y.
0. Box 822 -Belmont,Ca. 94002
PHONE
ORDERS WELCOME
(415) 592 -8097
CIRCLE NO. 22 ON READERS SERVICE CARD
100
gh L
e
D
all-new
1975 COMMO ICATIONS
HANDBOO;'Ir.
CONVERT any television to sensitive, big- screen oscilloscope. Only minor changes required. No electronic
experience necessary. Illustrated plans. $2.00. Sanders.
Dept. A -33, Box 92102, Houston, Texas 77010.
Here is everything r"
you want to kr>k4need to know
` i
about Citizens" land;
11725.
WILL SAVE BIG MONEY! Surplus, Clearouts,
Bankruptcy, Inventory, Deals. Catalog $1 (redeemable).
ETCOA Electronics, Box 741, Montreal, H3C 2V2. U.S.
Inquiries.
CONSTRUCTION PLANS: Laser.. $2.00. Rocket Tracking
Transmitter... $2.00.
Space
Monitor -Missile
Tracker
$2.00. Free Catalog. Electro- Research, P.O. Box
20285, Ferndale, Michigan 48220.
CD IGNITIONS, VHF/UHF monitors, crystals, CB radios,
Southland, Box 3591 -B, Baytown, Texas 77520.
1
Amateur Radi.q,
^:'I
Shortwave Listeni4
r
ri
CRYSTALS, Scanners, $3.88, include make and frequency.
G Enterprises, P.O. Box 461PC, Clearfield, UT 84105.
PRACTICAL Applications of Digital IC's. 100's of tips.
circuits, projects, on TTL. 443pp $19.95. Money Back
Guarantee. GEA, P.O. Box 285, Northfield, Ohio 44067.
CATALOG. Kits, Components, audio equipment.
Electronic Supply Pacs. Box 175. Floral Park N.Y. 11001.
FREE
ALPHA/THETA BRAINWAVE biofeedback instruments.
Analog instruments from $125; digital processing systems
from $225. BioScan, Box 14168 -E, Houston, Texas 77021.
SURPRISE! Build inexpensively, the most Unusual Test
DON'T TURN
n fióct don't even buy
a dial or any ,h(n e %e nil you've checked
tions Handbook.
out the 197./ Cc, r mu
Whatever y.ur
a
clalty whether
etting started
you're an 011
II help you get
this vital
ent out of every
greater valu g
minute you een
equipment.
-
Readouts! Catalogue Free! GBS, Box 100A, Green Bank,
West Virginia 24944.
ORGAN KITS, KEYBOARDS and many
components. Independent and divider tone generators. All
diode keying. I.C. circuitry. Supplement your Artisan
Organ, 35 cents for catalog. DEVTRONIX ORGAN
PRODUCTS, Dept. C., 5872 Amapola Dr., San Jose, Calif.
ELECTRONIC
95129.
ELECTRONIC IGNITION: Capacitor, transistor, pointless.
Auburn sparkplugs. Information 10 cents. Anderson
Engineering, Epsom, N.H. 03234.
WHOLESALE Scanners, CB, Crystals, Directories,
SSB /AM, Catalog 25 cents. G- Enterprises, Box 461P.
Clearfield, Utah 84105.
ELECTROENCEPHALOPHONE: Brainwave monitor.
Professional biofeedback intruments. J&J. 8102 -E,
Bainbridge, WA 98110.
HOBBYISTS -For all your electronic parts requirements at
low prices, send for free flyer to: Dartek Electronics, Dept.
P, Box 2460, Dartmouth, Nova Scotia, Canada. U.S. Inquiries.
CALCULATOR OWNERS: Use Your + -x= calculator to
compute square roots, trigonometric functions, logarithms,
and more! Quickly, Accurately, Easily! Send today for the
First and Best Calculator Manual
now in use throughout the world
still only $2.00 Postpaid with Unconditional Money -Back Guarantee! Mallmann Optics and
Electronics, Dept. 21A, 836 South 113, West Allis,
Wisconsin 53214.
FREE 1975 Electronics Catalog. McCord Electronics, Box
276 -N, Sylvania, Ohio 43560.
BUBBLE ETCHER. Etches 6 "x8" board in half time. Acrylic
construction. Complete photo process instructions.
Requires inexpensive aquarium pump. $12.00. ETCHER,
Box 25066, Northgate Station, Seattle, WA 98125.
AUTORANGING DMM, deluxe VOM's, logic probes and
more. Lowest prices. Free catalog. Electro Industries, 4201
Irving Park, Chicago. Illinois 60641.
ARE YOU PREPARED? 10,000 cubic foot, pull ring ignited
emergency smoke grenades are now available! 3 for $7.50,
9 for $20.00. Postpaid. Pacific Aero Supply, Box 601,
Malibu, Calif. 90265.
DIGITAL/ANALOG PLANS for Home and Lab!!! Send for
16
-page
ideas
catalog
featuring
the
-
,
'.
Instruments, Futuristic Gadgets using Numerical
EXPERIMENTER'S COMPUTER SYSTEM, practical plans,
tutorials, etc. M.P. Publishing Co., Box 378 -P, Belmont,
P.
ome th
th
YOU
free
Electronics
V
new
COMMUN
is sche
nation
75
IAf 1 lfS ANDBOOK
d t qot on sale
¡tie b:
21, 1974.
YOU CAN RESERVE
YOUR COPY NOW
AT THE SPECIAL
PRE -PUBLICATION
PRICE OF ONLY
$1.00 POSTPAID.
Regular newsstand price is $1.25,
mail order $1.60.
So to make sure you come through
"Loud and Clear" in 1975.. .
RESERVE YOUR COPY NOW AND SAVE
WITH THIS SPECIAL PRE -PUBLICATION
OFFER AVAILABLE TO READERS OF
POPULAR ELECTRONICS MAGAZINE ONLY.
PRE -PUBLICATI
RESERVATION F
Communications Handbook
PE -1174
Ziff -Davis Service Division
595 Broadway
New York, New York 10012
Enclosed is $1. Please reserve my copy of
the 1975 Communications Handbook at the
special pre -publication price to be mailed
to me on or before November 21, 1974.
Print Name
-
Address
Massachusetts 02178.
City
PYROTECHNICAL chemicals, casings, tools, supplies,
fuse. Price List 50 cents. Westech, Logan, Utah 84321.
VIDEO GAMES- attaches to your TV. Ping -Pong plans
$3.50. Information 25 cents. Duncan Electronics, 20650
Runnymede, Canoga Park, Calif. 91306.
State
Zip
PAYMENT MUST BE ENCLOSED WITH ORDER
POPULAR ELECTRONICS
AM -FMMULTIPLEX
100 -Watts
AMPLIFIER
music power
AM -FM-
99
MUXDIAL
WITH
indicators!
ESCUTCHEONFeature,. 4- speaker system. built -in
FM antenna.
record player jacks on separate panel.
Another external panel consiats of provisions for external FM and AM antenna, "satellite" speakers to
provide 4- speaker ground, jacks for connecting e tape
recorder to radio tuner or phono of cisterns to record.
Lower inputs for connecting tape deck that will play
back thou the Internal amplifier for systems. AC jack for
phono power connection. RED, GREEN and CLEAR indicators for Phono, AM. and FM respectively. Includes
d indicator on front panel for STEREO indicator.
Has separate input to plug into mike, guitar and other
musical instruments as well as another jack for plugging in s pair of stereo headphones.
ilaa controls on front panel. PHONO STEREO- AM -FM, MONO, FM STEREO, GUITAR, TAPE,
MIKE master control switch. LOUDNESS, BALANCE,
TREBLE, BASS controls, with power ON -OFF rocker
witch, and AFC ON -OFF. Designed for all audio -philes
to use as
all unit in DEN or FAMILY ROOM, or con trol unit by easy chair in family room, or for those
who wish to design their own console or modular nysAll sala stoop estes a.cultrr
tern. With 6 ft. 115 VAC cord and plug. Only 13 x 2
.
Rae DIRT
7
31/2" deep. No escutcheon. but we include template AB Peraw, All nmllo Use.
for one, plus diagram. Shpg. wt. 3 Ibs. With knobs
STEREO
AMP
S'
60 -WATT STEREO
AMPLIFIER
4
With Tremolo
$7.95
AMPEREX
Musical instrument amplifier at low, low price! Peak
power output 10 watts. Two input circuits are equalized for normal or solo guitar. The four controls are
VOLUME, TONE. TREMOLO INTENSITY and TREMOLO
SPEED. '!'here are terminals on board for normally open
foot awitch connection. Supply voltage 18vdc. Output
to 8 ohm hi- quality peaker. Input impedance 33,000
ohms. Current drain s20 mile. External power supply
required. Wt. 1 Ib. With instructions, hookups and
diagrams. Size 8 x 23/4 x 3.
a
0
oing audio
The- most a
io offer fur the hi -fi -ers. PA
RIO an ideal s usa for the family den, or any room in tthe
office, etc. Comes complete with hookup, escutcheon, and knobs. 5 separate controls: LOUDNESS.
house,
BALANCE, TREBLE, BASS, circuits switch for PHONO,
TUNER, TAPE, MIKE, AUX. 3 switches for SCRATCH
FILTER, RUMBLE FILTER, and POWER "ON- OFF"' with
built -in lite. 4- output transistors, each 30 Wail, Separate aaccessory mounting panel for 4 speaker attach ent, mike
cal instrument jack, tape, tuner,
ami mower jacks. 6 -oft. cord set for 115VAC. no cycles.
Measures only 13 x 7 o 3" Wt. a Iba. With attractive
muiti -color escutcheon. Mate by leading US maker.
20- 20,000 Cycles Mesa
4- Channel Spar. Systems!
7- SEGMENT LED
(All "LED" TYPES)
$3.75
1.49
2.50
.27
.12
.19
MAN'
SLA-1
for $3.
3 for $6.
3
Type Watts Sala
10 s 8.68
SI -1010Y
IB.9B
25
51 -1026[
sI -logoE SD 2s.9s
tape decks, FM tunsystems,
hi
-fi
in
extensively
stereo components,
ers, record player
within r/2 db from
P.A., etc. All alrlpl(fl properly heat- sinked, with
to 100,000. Each unit
tie lug connections.
heavy -duty connecting Power supply require 24VñCnded pushpull output.
Stock No.
Output to 8 ohms. Order by
SANKEN HYBRID
AUDIO POWER AMPS
"DIP"
as
Low
28 -Pin
24 -Pin
28 -Pin
24 -Pin
MM5314
40 -Pin,
MM5316
MM5316 -A no alarm
6 -digit
4 -digit
6 -digit
6 -digit
4-digit
SN7400
$7.77\íi
..
Alarm
I
7.77
7.77
7.77
0.88
4.95
(
$N7404
SN74O5
INTEGRITY
$2.50
56.00
Delivers :1..5 watts continuous. 10 watts peak. N h
heat inks: micro-mini size: s/ xl /zx'/z'!t 9 to 30V sop
ply. High sensitivity. N to 16 ohms.
6 -8 -12 DIGIT
Your óheice
gelIl@mIlcaop
-
$16.95
E
20 -Years
20 -Years of
LOWEST Eeo
PRICES,
-
Key parts include: CT5001
12 DIGIT BASIC 54
chip, 4 -3 digit readouts, factory etched PC board. case,
2- resistor networks, decimal switch.
carrying ca
Rovers Keyboard with ON -OFF switch diagrams.
Saie 524.95
-
Key parts
for 4- memory calculator. Case with "slight touch key hoard", CT6005 memory chip, 6 MAN 3's, ON -OFF
Itch, book, (extend key allows 12 digits), pc
boards)
.
$19.95
NOVEMBER 1974
Y1
48 -HR. SERVICE
moNo
DIGIT BASIC "MEMORY" KIT jj5
s'
GUARANTEES Bark
BASIC KIT 111
includes case, all- function Flex Kr,
Keyboard, Cal Tech CT5002 calculator chip, 9 -digit
Antex LEI) display with built -on individual magnifiers,
plus sheets.
BASIC KIT @2
me as Basic 51 except calculator
chip is National 8 -digit MM6725.
BASIC KIT 13
same as Basic 51 except calculator
chip is National 6 -digit MM5736 and 75492.
12
q-
20-Years of
WITH DATA SHEETS
3 FOR
7 SN7402
] 5N7403
.
600
On A..... es.
LINEAR
a FACTORY
OMIT
.75
.95
1.25
1.50
1.98
2.25
2.50
trteltY
erD
Na
rate op -amp (T0 -5) ....$2.50
2 50
Micro power 741 (TO.S)
2.50
Micro power 709 (TO -5)
2.95
FET Input op amp (TO -S)
1.25
Timer 2 u Seconds to 1 -hr. (A)
2.10
5 Times faster than 741C
1 00
558 Dual 741 (DIP)
2.95
560 Phase lock loops (DIP)
2.95
Phase
lock
loops
(DIP)
561
2.95
562 Phase lock loops (DIP)
565 Phase lock loops (A)
2.95
Sae Function generator (TO -e)
2.95
D 567 Tone decoder (A)
2 95
.49
702C Hi- grain. DC amp (TO -5)
1.50
D 704 TV sound IF system
.33
0 711C Dual dí9. comp (A)
723C Voltage regulator (A)
.69
741CV Freq. comp 709 (Mini DIP) .. , .44
44
748C Freq. adj. 741C (A)
1.75
753 Gain Block
531
532
533
536
555
556
HI slaw
.
.
739.739 Dual
741 -741 Dual
U ULN2300M Op
CA3065 Video
RC4195 Dual
preamp
98
.89
1.00
1.00
1
.
741C (TO -5)
amp with SCR
Audio system
2.50
15V Tracking V.R.
2.50
4136 Quad 741's (DIP)
RC -2556 Dual 555's ,
2 25
1.00
TVR -2000 Super 723. TO -5
BRAND NEW LOWEST PRICES (A) TO -5 or DIP
BUY AMY 10 -TAKE 15%
TAKE 25%
BUY ANY 100
.....
.
-
$3.98
35 WATT AUDIO
AMPLIFIER BASIC
2
for
D0
't
III
;7
Stgneti,'
340 :f0 transistor high power driver TO-5
"IC ", with a pair of complimentary 15watt plastic transistors, i.e. 2N5296 non
and 256109 pop. With schematics, printed
circuit and parts board layouts.
F'or Clans AB use. Basic includes:
....
3 for $17.
3 for $21.
3 for $27.
3 for $12.
3 for $12.
Inflation-Fighting
ECONOMY IC PRICES
] 5N7401
1)._..
BRAND NEW LOWEST PRICES
GENERAL ELECTRIC 3 -WATT
AUDIO AMP
CHIPS" 44
S
300
400
500
12- Digita, 40 Pin
.$5.95
9 -Volt version of 5001
7.77
CTSO05 12-Digits. 28 -Pin
9.99
with 3- function memory.
MMS725 8- Digits, 4- Font. LED 4.95
MM5736 6- Digits, 28 -Pin. 9V
4.95
"CALCULATOR
Sale
PRY
D 1óó
Tab Plastic Units
CT5001
CT5002
NATIONAL
Type
as
$7.77
TAKE 25 %
o
....
LOWEST PRICES ON
-
SCRS! TRIACS!
QUADRACS!
Ae
30 -Amp Power
`..p
...
/It
Mlgr'
ON A
MMS311
MM5312
MM5313
15, 18. 24V ....2.95
LM -350 Dual Peripheral Driver DIP
.69
LM -370 AGC Squelch op amp, TO-5
1.50
LM -371
1 25
N.E. 1 -F, op amp
3 50
LM -373 AM -FM SSB I.A.D. TO-5
350
LM -374 AM -FM 55 IVAD TO-5
LM -376 Pos. V. Reg.
,65
LM -377 Dual 2-watt audio amp
2.69
LM -380 600mW LM -380, mini DIP
1.69
LM -381 Low noise dual pre amp DIP . , . 1.69
LM -382 Low noise dual pre amp DIP . . . 1.89
p LM -703 RF -IF amp. TO-5
59
LM -703M RF -IF. op amp. mini DIP
51
36
LM -709 Operational amplifier (A)
45
LM -710 Differential amplifier (A)
LM -711 Dual Differential Amp (A)
36
69
LM -723 Voltage Regulator (A)
69
LM -725 Instrument Op Amp
175
LM -733 Differential Video
41
LM -741 Freq. Comp. 709 (A)
41
1M -741CV Mini DIP 741C
LM -747 Dual 741 (A)
89
41
LM -748 Freq. adjustable 741C (A)
LM -1303 Stereo era amp DIP
91
LM -1304 FM Stereo Multiplexor
1 25
91
LM -1307 FM Multi. Stereo Dem. DIP
LM -14$8 Dual 741's mini DIPs, TO-5 .
63
LM -1496 Modulator, Demodulator
1 00
amp
1 SO
U LM -3028 Diflerent,al NF
95
LM -3900 Quad 'current mirror" amp .
2 SO
LM-4250C Programable op amp
44
LM -75451 Dual peripheral driver
LM -75453 Dual inerioheral driver ..
.. 44
E LM- 75491 Ouse seg. driver, LED (DIP) ... 1 65
LM -75492 Hex digit driver, 250ma. DIP. 1 85
TAKE 15%
THIS AD
BUY ANY 100
...... .......
....
REFLECTIVE BAR TYPES
MAN
SLA-3Y
3 for $5.
2.10
SLA-1 .33
sir Opcoa, equal to
4.95
3 for $13.
SLA-3 .70
3 for 56. MAN -1 or MAN -4 .pees. Color - REO
2.50
SLA-II** .33f
SLA21 .33 tt 2.50 3 for $6. t(:reco. te reilw
CLOCK CHIPS
LM -300 POS V.R. (super 723) TO -S
81
LM -301 Hi- performance op amp (A)
39
LM -302 Voltage follower TO -5
81
LM -304 Neg. volt. Reg. TO -S
.1.15
LM -305 Pas. Voltage Reg. TO-5
95
LM -307 Super 741 op amp (A)
39
LM -308 Hi -Q fat type op amp TO -5
1 09
LM -309H 5V Volt - Regulator TO -S
1 05
LM -309K 5V Volt. -Reg. 1 Amp TO -3
. 1 65
LM -310 Voltage- Follower TO-5
1 25
LM -311 Hi -perf. Volt. Comp. (A)
1 09
LM -318 Prec. Hi -Speed DIP
1 95
LM -319 HI -speed Dual Comp. DIP
.
1 50
LM -320 MINUS 5. 12 or 24V V.13..70-3 1 50
LM -322 Prac. Timer
1.75
LM -324 Quad (4 -741's in DIP)
2.19
LM -339 Quad Comparator. DIP ..
.
1.75
LM -340 Pos. V.R. 703.1 -Amp 5, 6, 12,
....
Readouts
Special
3 for $9.
Each
Char.
Type
MAN -1
MAN -3
MAN -4
BUY ANY 10 IC'S
...
60 -WATT STEREO
HIGH FIDELITY Tape, Record Player, PA
8 Musical Instruments!
AMPLIFIER
$3995
95
-*NATIONAL
IA) TO -5, Dip
LINEAR OP AMPS er mini Dip
SOLSTATE
WATT GUITAR AMP
with printed
circuitry throughout,
Featuring solid state 10
power per
watts "peak" audio
circuit construction. walnut
veneer grain with chrome
channel. Handsome
provisions for separate TREBLE,
trim escutcheon. With STEREO
HEADPHONES,
on mounting items as
controls, separate PHONO
BASS, BALANCE, VOLUME separate
OFF-ON POWER
AND AUXILLIARY with
x 3 x 2". Separate
switches. Chassis size 111/2
type jacks, with
has right and left speaker phono
and Auxilpower outlet for tape of phono
convenience
plate
tape decks, and
with
amplifier
liary Inputs, for using
cables for stereo
other equipment. Separate external
ON -OFF
separate
phono connections, 6 -ft. power cord,
automatic turntable power plug.
light indicator,
2 !bale
of
set
ator
with
20 -WAMTT
597406
SN7407
597408
597409
597410
597411
597412
SN7413
5N7414
597415
SN7416
5N7417
597420
SN7421
597422
597423
597425
597426
597427
Saie Order
5.19
.24
.19
.27
.24
.79
.48
.27
.27
;19
.31
.55
.89
2.25
.45
.45
.50
.22
.50
.29
.32
.35
.31
.35
by type number! spec :b reis on request
o
.24
.28
597437
.45
5017438
.49
597440
.19
SN7441 1.00
SN7442 1.00
597443 1.00
SN7444 1.00
597445 1.00
5N7446 1.10
597447 1.10
597448 1.45
.27
5)17450
.28
557451
597453
.28
S147454
.39
597455
.28
5147460
.26
597461
.26
597462
.39
SN7464
.39
SN7430
5N7432
597465
597470
597471
o
o
o
o
o
o
o
o
o
-39
.49
-55
597476
597478
597480
597481
SII
Factory Marked
5974107
5974108
5)174112
5)174113
5974114
5974121
5974122
5974123
5N7482
5974125
SN7483
o 5N74126
597485 2.50 o 5974139
597488
.49 o 5974140
5N7489 2.95 o 5974141
597490 1.81 o 5974145
597491 1.35 o 5974148
597492
.99
5N74150
597493
.99 o 5974151
597494 1.05
5974153
5N7495
.99
O 5974154
SN7496
.98 o SN74155
5)174100 1.55 o 5974156
5974104 1.25
SN74157
5974105 .95
5974158
5)174106 ,95
9974160
.S2
Discount:
Your Choate
CIRCLE NO. 31 ON READERS SERVICE CARD
2.95
1.19
.99
1.39
1.69
1.29
1.45
5N74394 1.89
SN74195 1.10
S1174196 1.20
5974197 1.10
5N74198 2.45
5974199 2.45
SN74200 7.50
1.4S
1.45
1.85
r
each
y
%
.....
.50
10-Pins. .29
a -Pinr (or
Min1,00DIP) - 39
14 -Pin, Wi
Wrap
69e
16 -Pin, Wire Wrap ...89c
001O -5, B
a
...
.
Rated: net 30
Terms: add postage
Phone Orders: 11':Orefield. Mass. (617! 245 -3829
Retail: 16-15 Del Carmine St., Wakefield, Mass.
Rater Str,'et C.O.D.'S MAY BE PHONED
20e CATALOG on Fiber Optics, 'ICs', Semi's, Parts
MINIMUM ORDER
$4.00
Volts
y
SN74180 1.10
SN74181 3.95
5)174182 1.05
5974185 2.34
SN74187 2.34
5974192 1.59
5N74193 1.59
016 -Pin, DIP
Bay Any 3
Take 10%
Take10
T
.49
.55
1.09
.65
,89
1.25
2.50
1.19
1.19
14 -Pin, DIP
..5.45
14 -Pin, Side Mount 1.00
l
$1.75
5574161 1.59
5974163 1.75
5974164 2.85
SN74165 2.85
SN74166 1.85
5974173 1.85
5974174 2.25
5974175 1.99
5974176 1.25
5574177 1.25
.49
.95
.95
,95
.95
INTEGRATED CIRCUIT
SOCKETS
TO -220 Cass
1 Ais
POSITIVE
SITIVE VOLTAGE
Type
O
.79
.59
1.25
.99
1.19
NEW!
NATIONAL
LM -340T VR's
LM-340-05T S
LM -3 40 06T
6 v
LM-340-08
LM340- T 12
LM. 340 -15T 15vv
LM- 340 -18
=M- 340
ü
-24 T 24 v
A
'
,42
.52
.39
.91
5)17472
SN7473
5N7474
5)17475
i
0
-
POLY PAKS
P.O. BOX
942E LYNNFIELD,MASS. 01940
101
BURGLAR -FIRE ALARM components, hardware. Free
Catalog- Information. Si!mar, 133 S. W. 57 Ave., Miami,
Florida 33144.
BUGGED???
Rid Electronic Snoopers. Countermeasure
Equipment Catalog $1.00. Security, Box 671, Westwood,
New Jersey 07675.
MULTI -PURPOSE OSCILLATOR: 200-5000 HZ., Parts
below $8, Thousand uses, Plans $2. TECHNICAL
BOOKLET "Oscillators", $2.50. IC POWER SUPPLY, Plan
$1.90. Littleton Hobby Circuits, P. O. Box 453, Littleton,
Mass. 01460.
LIQUID CRYSTAL. 3 -1/2 digit wristwatch display. New,
with instructions for building wristwatch. Final close -out.
Less than original, factory wholesale price. $5.50 each.
Two for $10. Tricounty- Winslow, Inc., Box 5885, Grand
Central Station, New York, N.Y. 10017.
FREE KIRLIAN image on 35mm slide and details on Kirlian
equipment. Systecon, Department 30, Box 417, West
Hyattsville, Maryland 20782. (301) 596 -5654.
CIRCUIT board service. Circuit boards made from your
layouts. Send for information. Printed Circuits, 22 Maple
Avenue, Lackawanna, New York 14218.
NEW COLOR TELEPHONES, booklets about connecting
telephones, and telephone accessories. Details 25 cents.
Telephones, Box 29002 -C, Queens Village, NY 11429.
FIREPLACE heat exchanger. Use All Heat. Plans $3.00.
Jennell, 6030 O'Day Dr., Centreville, VA 22020.
SPEAKER enclosure 10 x 15 x 6, walnut finish, $4.00 each
ppd. Complete case listing 50 cents. DigiTel, Box 6585,
Toledo, Ohio 43612.
CITIZEN'S radio. Free discount catalog. Capitol Sound,
Box 3523, Des Moines, Iowa 50322.
CARBON FILM RESISTORS. Brand new as low as 2 -1/4
cents. FREE samples and specifications. COMPONENTS
CENTER -PE, Box 134, New York, NY 10038.
7,000 SEMICONDUCTORS, 100's Electronic Circuit Kits,
Technical Reports, Energy Conservation, Computers. Cat.
50 cents. E/S Lab, Box 738, College Park, MD 20740.
UNSCRAMBLERS: Fits any scanner or monitor, easily
adjusts to all scrambled frequencies. Only 4" square
$29.95, fully guaranteed. Dealer inquiries welcomed. PDQ
Electronics, Box 841, North Little Rock, Arkansas 72115.
INTEL 8008: $59.45; 8038: $5.95; 1101 RAM: $2.25; 1103
RAM: $4.50 2513, 2516: CHAR. GEN. ROMS: $12.75.
ELECTRONIC DISCOUNT SALES, 138 N. 81st St., Mesa,
AZ 85207.
TROUBLE getting parts for projects? Let us buy them for
you. Parts buying service. Box 1026 -P2, Fremont, Calif.
94538.
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FACTS NEVER BEFORE PUBLISHED FOR THE PUBLIC
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Or 4
TC
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IVE
-- Sample coin 25t EN 105 BOx ras.c.....
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LASER TUBE
$23.50; Five Laser Plans
$4.00; Catalog
$1.50, "PE 1074 ", Plasma Scientific, Box 1005,
Claremont, Calif. 91711.
-
DIAGRAMS, Radio, TV,
etc., $2.00. CIRCUIT design
service, request quotation. TECHSERVAS, Box 1167,
Berkeley, CA 94701.
SOLARWIND ... The New Sun Power - Wind Power Newsletter ... News, Theory, Experiments, Projects, Plans ...
Sample Copy $1.00. Malmann Optics and Electronics,
Dept. K1, 836 South 113, West Allis, Wisconsin 53214.
ELECTRONIC COMPONENTS -all kinds, send for free
catalog. Epic, Box 20152A, Minneapolis, Minn. 55420.
ANTIQUE RADIO SCHEMATICS. Send SASE. Sterling, Box
P.O.
r
Information Free.
PHOTOLUME
TESLA COIL -40" SPARKS! Plans $7.50. Information 75
cents. Huntington Electronics, Box 2009 -P, Huntington,
Conn. 06484.
AMAZING ELECTRONIC PRODUCTS- Pocket Laser, See In -The Dark, Scramblers, Penlight Strobe, Energy Devices,
TV Disruptor, Many More, All New. Catalog $1.00.
INFORMATION UNLTD., West St., Milford, N.H. 03055.
PROJECT PLANS. New projects every month. Send for
complimentary copy. Electronic Projects Newsletter, Box
1026P, Fremont, Calif. 94538.
supply plans, great for IC experimenters! 2
channel, each regulated 0 -15 VDC at 1 amp, $5.00. Easy to
build, parts available from us. B&F Industries, 3603
Glenrose Ave., Altadena, CA 91001.
POWER
CANADIAN
DIAMOND NEEDLES and Stereo Cartridges at Discount
prices for Shure, Pickering, Stanton, Empire, Grado and
ADC. Send for free catalog. LYLE CARTRIDGES, Dept. P,
Box 69, Kensington Station, Brooklyn, New York 11218.
SAVE 50%. Build your own speaker systems featuring Nor elco, Eminence and CTS. Famous brands from world's largest speaker factories at lowest wholesale prices. Write for
free catalog of speakers and electronic accessories.
McGee Radio Company, 1901 McGee Street, Kansas City,
Missouri 64108.
KITS
ELECTRONICS
CATALOGUE
$1.00
(refundable on 1st purchase)
featuring
SINCLAIR hi -fi modules and calculator
kits, We will include the new 32 -page
Project 80 hi -fi module construction
manual.
AMTRON electronic kits -over 100 types'
Speaker k its and components
American enquiries welcome!
DLaDSTOfE- *ECTROR/CS
WANTED
QUICKSILVER, Platinum, Silver, Gold, Ores Analyzed.
Free Circular. Mercury Terminal. Norwood. Mass. 02062.
I
F9121
F9082
Two popular HONEYWELL computer boards. filled with many
types of components.Transistors, diodes, precision resistors and
capacitors,zeners, heat sinks trimmers etc. Some of the F9121
boards have MADT high Freq. transistors.
414"x12"
STOCK NO.F9121
3 boards $2.00 9 boards $5.00
STOCK NO.F9082 2 boards $1.00 12 boards $5.00
EXOTIC COMPUTER BOARD GRAB BAG
!
!
Due to the huge success of our anniversary sale we
are extending the sale prices to December 21.
Our catalogues 250 t+apizdEtÁla. With
lsi. order
POWER SUPPLIES. Use them in all your projects!
F0510 5v 1.5 amp. was $ 8.95 NOW Only $7.95
F1210 12v 1.5 amp. was $ 9.95 NOW Only $8.95
F1510 15v 1.5 amp. was $10.95 NOW Only $9.95
Predrilled epoxy board and all parts included except
transformer. Transformer PC -16 $4.60 extra.
,
N,,1
I
1736 AVENUE RD.,TORONTO,ONT.
M5M 3Y7. DEPT. PE -11
PRICES SLASHED
s,
Ill
PPD.
CORPORATION, PO Box 139, New York, N.Y. 10016.
UNIQUE
HONEYWELL COMPUTER BOARDS
r
$20.00
HIGH FIDELITY
30eR
,1N
TRIGGER SWEEP GENERATOR- improve your low cost
scope by adding solid state trigger sweep. Complete kit,
202, 06878.
3.00
S
PLANS AND KITS
Our unexcelled quality 5% carbon FILM %2
watt resistors now only .07c each, minimum of
5 each value. Get them while they last!!
I
All Electrolytic and film capacitors reduced 10 %.
This lot of boards are the very latest from G.E., Xerox &
other top manufacturers. These boards contain expensive
components, such as reed relays, SCRs, power transistors,
heat sinks, trimmers etc. All late (1973 & 1974) boards.
At least 1 part on each board is worth more than our price
for the entire board. We have seen boards in this lot with
as many as 9 reed relays. Money back is not 100% pleased.
STOCK NO.F9934 7 different boards$10.00, 21/25.00
HIGH POWER AMPLIFIER TRANSFORMER
This transformer is ideal for high power applications.Winding
1, 64 volts ct @8 amps, tapped at 32 volts ct. @ 8 Amps.
Winding 2 1fß volts ct. @ 8 amps. Winding 3, 400 volts @ .15 A.
This transformer easily delivers over 500 watts. 4% "x4"x4 ".
STOCK NO.F9905 Wt. 10 lbs.
$11.95 ea. 2/22.00
MINIMUM ORDER $5.00. Include postage, excess refunded. New
edition of our catalog now available.
L
BOX 1.
CIRCLE NO.
102
L,
DELTAYNELECTRONICS
MASSACHUSETTS 01903
Phone (617) 388-4705
11
ON READERS SERVICE CARD
CO.
',
NEW ITEM!! We've got Hewlett Packard red
LEDs for only 39c each. Includes Panel mounting hardware. T-13/ size. Part no. 5082.
If you're serious about quality then you'll
want our new MAN71 series of displays. They
. are typically 50% brighter than the old MAN
7 series. We've got them in Red, Yellow and
Green. All .3" char. ht. With each display we
will include one HP 5082 panel indicator LED. $4.00.
We also have 3 sizes of display bezels and filters that
will fit most of your needs. Plus we have 7400 series
logic, transistors and many other Brand New first
quality parts and kits. NO C.O.D.'s please.
Mastercharge and Bank Americard Accepted.
Tracy Design Corporation
15870 Schaefer
(3r9)
83(3
- 25-0i
Detroit, Mi. 48227
CIRCLE NO. 38 ON READERS SERVICE CARD
POPULAR ELECTRONICS
LIVE IN THE WORLD
OF TOMORROW. .. TODAY!
WAR SURPLUS
And our FREE 164 PAGE CATALOG is packed
with exciting and unusual values in ecological and
plus 4,500 finds for fun,
physical science items
study or profit ... for every member of the family.
-
ELECTRIC GENERATOR
Brand new Signal Corps Model. Up to
90 volts by turning crank. Use in high
impedance relays. Charge ground &
bring up night crawlers for bait or
study. 2 Alnico Magnets alone now
worth more than original $15gov't cost.
A BETTER LIFE
STARTS HERE
"FISH WITH THE
"400 POUNDER"
MASSIVE NEW 576X
6" REFLECTOR
Massive 12 lb. permanent magnet lifts 400
lbs -most powerful we've ever sold. Provides
instant handle for easy, safe metal carry, great
for retrieving metal parts. Releases quickly
pivoted side handle, sever magnetic grip!
Use for flame cutting, shearing, punching,
positive ground for welding; remote usage, etc.
Tie a line to it and go treasure hunting at sea! Powerful ceramic magnet lifts more
under water (best through 1" steel plate).
No. 85,238AV (13'hx5x5)
865.00 FOB.
-lift
Great for astrophotoyraphy! Features 48" F.L.
f/8 Pyrex w: parabolic mirror acc. to r/a wave;
massive equatorial mount (usually found only
on 8 "); precision 2" I.D. heavy duty rack & pinion
focusing mount capable of supporting any
camera w/o special holder. Inch: electric clock
drive w/ manual slow- motion control, deluxe widefield 6X finder w/ crossline reticle; 3 eyepieces; 1 ", 48X Kellner; 1/4" 192X
Ramsden; Barlow to dbl & triple power. 24" wobble -free metal base.
No. 85,248AV (SHP. WT.
200 LB)
$99.50!
He -Ne LASERS FROM
min- HI- PERFORMANCE
FOB
A MAGNET
hunting on the bottom! Fascinating
fun & sometimes profitable! Tie a line to our
powerful new specially designed 150 lb. pull
Magnet -drop it overboard in bay, river, lake or
ocean. Troll in along bottom -your "treasured"
Go treasure
-
1.0mW
Diverg.
$499.00
"FISH" WITH
Edmund quality, TEMoo mode, cold cathode for
long life. Completely self- contained units; solid
state power supply; 110v AC. 0.3mW min
GREAT GENERAL PURPOSE LASER: 1.2mm
beam dia., 2.OmRad beam Diverg.
Stock No. 79,061AV
$8.50 Ppd.
(2 lbs.)
No. 50,225 AV
$99.50 Ppd.
LAB LASER: 1.2mm beam dia., 1.OmRad beam
-
Stock No. 79,050AV
$150.00 Ppd.
3.0mW min
DEPENDABLE HI- POWERED LASER: 1.0mm beam dia 0.8mRad
beam Diverg.
,
Stock No. 79,052AV
$325.00 Ppd.
-.-
haul can be outboard motors, anchors,
other metal valuables. Has 6 stacked ceramic magnets. Lifts more than 150 lbs.
under water!
No,
71,135AV
-
... (31/4x37/8")
...
$17.50 Ppd.
75-LB. PULL (1 LB.) W/ 3 CERAMIC MACENTS
No. 71,150 AV
(1- 11/1603'/4 ")
$11.00 Ppd.
AUTHENTIC SCALED
TAKE TEMPERATURES
IN SECONDS
WINDMILLS
Real -thing replicas show wind direction, wheel silently revolves on ball
bearings. Give your grounds unique
rural charm! Great centerpiece for
planter, flowers. Use to hold yard
light, house number, sign or as mailbox. For school, a fine "energy crisis"
science project
does everything but pump water. Heavy
gauge steel, durable outdoor finish; aluminum color w /red trim.
Edmund's new electronic oral thermometer obsoletes glass mercury type. Seconds instead of
minutes, more accurate, much easier to read!
Put disposable cover (supply incl.) on flexible
probe, place under tongue, push button, dial
meter center, read temp fast in F.° & C.C.
92- 106 °F. (33- 41 °C.) in 1/4° increments,
97- 101°F. to 1 /10 °. Safe, hygienic, no squinting. Compact metal case fits in
doctors', nurses' shirt pocket. Incls 9v trans batt., instrs.
Stock No. 42,210AV
-
--
$25.00 Ppd.
8 FOOT
46
$10.95 Ppd.
$32.50 Ppd.
$44.95 FOB
(17" DESK MODEL)
No. 71.924AV
No. 85,229AV
No. 71,923AV
14 LB.
4'/2 FOOT
LB
...
THE MOST POWERFUL
130 EXPERIMENTS IN OPTICS
and photography! Optix® Experiments Kit is a complete optical and
photography lab for 130 exciting experiments. Lets you recreate the periscope, telescope, microscope, kaleidoscope! Build a 35mm reflex camera
with interchangeable lens system!
Make, develop photographic film! Enjoy the fun and fascination of having your own optics lab. Fully
illustrated 112 -pg. manual, 8y x 11 ", clearly explains usage of
this stimulating kit's 114 precision engineered components.
SOLAR CELLS
Price & technology breakthrough. Harness the
sun with these 2" dia. 500 mA@ .5V silicon cells
5 times more efficient per cost than ever
before! Need no plastic lens, are very flat, fit
almost any solar application. Hook up in series
for more voltage; parallel for more current.
-
No. 42,145AV ...(TAB LEADS)
PIE- SHAPED '/s 2" DIA. 100 mA. @ .5V
No. 42,146AV ...(TAB LEADS)
15/16" DIA. CIRC. (1/16 THICK), 100 mA. @ .5V
No. 30,538AV
(WIRE LEADS)
$11.50 Ppd.
...
$7.95 Ppd.
Stock No. 71,646AV
$24.95 Ppd.
$6.95 Ppd.
AERONAUTICS FUN KIT (100 Experiment)
Stock No. 71,840AV
$15.95 Ppd.
MAIL COUPON FOR
GIANT FREE
CATALOG!
164 PAGES
4500
Completely new Catalog.
I
MORE THAN
D
BAUNUSUAL
Packed with huge selection of telescopes, m,
-
croscopes. binoculars. magnets, magnifiers, prisms, photo components.
many
ecology and unique Lighting tems, parts. kits. accessories
hard.to.get surplus bargains. í00's of charts, Illustrations for hobbyists,
,mentors, schools, industry.
EDMUND SCIENTIFIC CO.
lee gdKelp eelldla$, earrlagtaa,
N.
EDMUND SCIENTIFIC CO.
300 Edscorp 8uilding, Barrington,
How Many
Description
Stock No.
1
enclose
Name
NAME
Address
ADDRESS
NOVEMBER 1974
t
p
Total
Add Handling Chg.: 11.00, Orders Under $5.00, 50K. Orders Over $5.00
I. NNW
state
N
PLEASE SEND
GIANT FREE
CATALOG "AV"
Please rush Free Giant Catalog "AV"
LT"
Price Bach
IL
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CITY
STATE
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105
GOVERNMENT SURPLUS
GOVERNMENT Surplus. How and Where to Buy in Your
Area. Send $2.00. Surplus Information, Headquarters Bldg.,
Box 30177 -PE, Washington, D.C. 20014.
ELECTRONIC Equipment and Parts. Big 36 page Free
Catalog. Send for your copy today! Fair Radio Sales, Box
1105-P, Lima, Ohio 45802.
MANUALS for Govt Surplus radios, test sets, scopes. List
50 cents (coin). Books, 7218 Roanne Drive, Washington,
D.C. 20021.
N.A.S.A.
SURPLUS EQUIPMENT, rack chassis, P.C.
Connectors etc., Catalog 25 cents. Computer Boards
10/$2.75 pp., ORION, Box 145, Springfield, Virginia 22150.
Washington Building, Washington, D.C. 20005.
PATENT Searches including Maximum speed, full airmail
report and closest patent copies. Quality searches expertly
administered with complete secrecy guaranteed. Free
Invention Protection form and "Patent Information." Write
Dept. 911, Washington Patent Office Search Bureau,
Benjamin Franklin Substation, P.O. Box 7167, Washington,
...Manufacturers Need
New Products
D.C. 20044.
If you have an idea for a new product, or a way to
make an old product better, contact us, the idea
I
FREE PAMPHLET: "Tips on Safeguarding Your Invention."
Write: United States Inventors Service Company, 708 -T
Carry Building, Washington, D.C. 20005.
FILE your own patent application. Complete information
and materials. Write: Inventor's Guide, 468 -R, Goodspeed.
Road, Virginia Beach, Virginia 23451.
industry, negotiate for casTh
e or licensing,
Send for our FREE "Invention Kit." It has a
special "Invention Record Form," an important
-
Ibrochure, "Your Invention Its Development, Protection & Marketing," and a Directory of 500
Corpo ations Seeking New Products. You'll learn
how ideas become a reality!
PERSONALS
E
MAKE FRIENDS WORLDWIDE through international
correspondence. Illustrated brochure free. Hermes, Berlin
11, Germany.
the
INVENTIONS WANTED
iji tor
in
INVENTORS: Protect your ideas! Free "Recommended
Procedure ". Washington Inventors Service, 422T
idea
INVENTORS!
RAYMOND LEE ORGANIZATION
'''','¡
230 Park Avenue, New York, N.Y. 10017
I'd like to find out how to take action on my
idea. Send Free "Invention Kit No.A-112"
peoplee
IName
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Please Print
Address
for patented, unpatented inventions.
Service, 2354-P Telegraph, Oakland.
CASH -ROYALTIES
Global Marketing
California 94612.
TRANSISTOR SPECIALS
2N256 PNP GE TO-3
$ .50
2N404 PNP GE TO-5
4/$1.00
2N1137B PNP GE TO-3
$ .95
2N1016A NPN Si TO-82
$.1.95
2N2226 NPN Sil-0-82
$2.50
MPS3393 NPN Si TO-92
4/$1.00
2N3866 NPN Si TO-5
$ .75
2N2369 NPN Si TO-18
5'$1.00
2N3767 NPN Si 10-66
$ .70
2N2222 NPN Si TO 18
5/$1.00
2N3055 NPN Si TO-3
$1.00
2N5296 NPN Si TO-220
$ .50
$ .55
2N6109 PNP Si TO-220
WITH 10:1 PROBE $495.00
MINIATURE TRIM POTS
5K, 10K, 25K, 50K, 100K,
3/$2.00
$35 EA.
MULTI -TURN TRIM POTS
Similar to Bourns 3010 style 3/16" x se"
x 11/4" 50,100. 500, 2000, 5000,10,000
ohms
$1.50 ea.
3/$4.00
PRINTED CIRCUIT BOARD
41/2 "x61/2" single sided
NIXIE TUBES
Similar to Raytheon 8650
tubes, with socket & data
sheet
$2.25 3/56.00
-
FPA -711
THESE PHOTO DIODE
ARRAYS ARE USED TO READ
SEVEN LEVEL TAPE 100 ma
SPACING
TIS73NFET
2N4898 PNP Si TO-66
MJ2252 NPN Si TO-66
2N3638 PNP Si TO-5
fiber
glass board, 1/16" thick, unetched
5/$1.75
S.40 ea.
CAPACITORS
6V 30 OF TANT. 5/51
8
profile calculator keyboard. A
23" x 31/4" x 42" flex key.
19SK -6 keyboard having 0 -9, e,
- -, K +C buttonswith
off, on switch.
$6,00
VERIPAX PC BOARD
a 1/16" single
sided paper epoxy board,
412"x612" (standard veripax),
TfL
DRILLED and ETCHED which
will hold up to 21 single 14 pin
IC's or 8, 16 or LSI DIP IC's with
busses for power supply connections. Is also etched for 22
pin connector
$5.25
74L0074007401740274037404740574067407740874107411741274137416741774207426742774307432743774387440-
5.50
S
S
S
40
90
60
40
...5.40
S
50
5.75
EA
10 WATT ZENERS
3.9. 4.7 OR 5.6
V
9
WATT ZENERS
56. 6.8 OR 12 V
$30EA
Silicon Power Rectifier
PRV
lA
12A
3A
50A
100
200
400
.06
.07
.09
600
800
000
,15
.20
.11
.11
.16
.20
.25
.35
.45
.30
.35
.50
.70
.90
1.10
.80
1.15
1.40
1.80
2.20
+
-15VDC AT 100 ma, 115VAC
INPUT
5VDC AT 1A, 115VAC
INPUT
IN 4148
$19.95
$19.95
14/$1.00
Terms: FOB Cambridge
Mass. Send check or Money
OrderInclude Postage.
Minimum Order $3.00
IC SERIES
.30
.18
.18
.18
.18
.22
.22
.37
.37
.24
.18
.30
.45
.75
.37
.37
.18
.30
.33
.18
.30
.44
.37
.21
7441 -1.05
7442 -1.00
7445 -1,10
2.60
REGULATED MODULAR
POWER SUPPLIES
$4.75
7446-1.15
74767480-
.47
.65
7483-1.10
7485-1.30
7486- .48
7489-2.75
7490- .75
7491-1.30
7492- .75
7493- .75
7495- .99
7496- .95
8220 -1.50
74107- .50
74121- .60
74123 -1.00
74125 -1.40
74126 -1.40
74150-1.15
74151-
.95
74153 -1.10
74154 -1.65
74157 -1.25
74163 -1.60
74164 -2.05
74165 -2.05
74173 -1,80
74176 -1.80
74177 -1.80
74181 -3.60
74192 -1.50
74193 -1.45
74195 -1.00
75491 -1.10
CD 4001
4009
4010
CD
CD
CD 4012
CD 4013
CD 4016
CD 4022
CD 4023
CD 4025
CD 4027
CD 4030
5311
CASSETTE
ais whi
$$.20
$1.25
$2.25
á
55
2A
.95 1.25
1.15 1,50
1.35 1.75
65
5314 -CLOCK CHIP
lus
25A
5.00
D
599
58.50
CHIP
55HÁ(6RA(6CqqTÉ66R
tigEgN
HÁRACTRxBESTATIC $11.50
sel
02
10)
neiger and Zone
.65
.60
.03
.025
2.12
.50
2.55
.50
.015
.55
.022
2.44
40
MI
.50
.02
2.39
.35
1.00
90
80
1.00
Minimum Order. 05.00
1776 COLUMBIA
WASHINGTON, D.C. 20009
1/2 INCH VIDEO TAPE. $7.25 per hour on 7" reel. Free
information. Oregon Magnetics, Box 13374, Portland,
Oregon 97213.
INSTRUCTION
LEARN ELECTRONIC ORGAN SERVICING at home all
troublemakes including transistor. Experimental
shooting. Accredited NHSC, Free Booklet. NILES BRYANT
SCHOOL, 3631 Stockton, Dept. A, Sacramento, Calif.
95820.
kit-
SANKEN AUDIO POWER AMPS
Si 1010 Y 10 WATTS
Si 1025 E 25 WATTS
Si 1050 E 50 WATTS
...$ 7.95
..,$18.88
...$29.95
LEARN WHILE ASLEEP, Hypnotize! Strange catalog free.
Auto -suggestion, Box 24 -ZD, Olympia, Washington 98501.
LINEAR CIRCUITS
LM 309K 5V 1A REGULATOR
723 -40 +40V REGULATOR
301/748 -Hi Per. Op. Amp
LM 320
or -15V REGULATOR .
LM 376 -V to 37V POS REG.
741A or 741C OP. AMP
7090 OPER AMP
340T -5, 12, 15, 18, 24V
POS. REG. TO -220
101 OPER. AMP.. HI PERFORM
LM 308 OPER. AMP., LOW POWER
747-DUAL 741
536-FET INPUT OPER. AMP.
537- PRECISION OP. AMP.
LM 3900 -QUAD OP. AMP.
LM 324 -QUAD 741
560-PHASE LOCK LOOP
561 -PHASE LOCK LOOP
565 -PHASE LOCK LOOP
567 -TONE DECODER
703 -RF -IF AMP
LM 370 -AGC SQUELCH AMP
555-2 us
2 HR. TIMER
3822 -TRANSISTOR ARRAY
LM 380-2W AUDIO AMP
LM 377 -2W STERO AUDIO AMP
LM 381- STEREO PREAMP
LM 382 -DUAL AUDIO PREAMP
LM 311
PER. COMPARATOR
LM 319 -DUAL HI SPEED COMP.
LM 339 -QUAD COMPARATOR
-5
-
$1.65
5.58
S
,
35
.51.75
S 58
5.35
8 29
$1.75
5.75
.$1.06
5.75
$2.60
$2.60
5.58
$2.20
$2.60
$2.60
52.60
52.95
5.55
$1.15
5.98
S
95
$1.45
I
145 NORFOLK ST. Cambrid
ISOLID STATE SALES
P.O. BOX 74A
SOMERVILLE, MASS.
Nolelco"
r 10000
$12.50
..-...511.50
m<sm
Transistors and Rectifiers;
by
bous hot
1
6 DIGIT HOLD COUNT,
OUTPUT STROBE ..
5316 -ALARM CLOCK
Postage
aper mailer
P01''9 met10lflher 000
OLD RADIO SHOWS on cassettes $1.50 per show. Free
Catalog. Radio Classics, Box 804, Mattituck, NY 11952.
6.00
BC
LABELS
cleaners,
catalog
discountL1hhlog.
SAXITONE TAPE SALES
4.00
DIGI
orelco cassette
s,
ssettecassettes.
brand
cotch Cassese SC9OHE, Buy 2, gel ONE FREE
0.1/2" Fiberglass Reels, Used
0.1 /2" Metal. NAB Bote, Used
Wave Bridges
6A
cassette abe
orelco Cassette Cleaner
mette Paper Mailer Boxes
$1.35
$
e
plastic
open reel and
rasette Labels (Multiples
$ 55
CLOCK CHIP 6
CgWI, OIIRO STROBE
1I01D
1930 -1962 Radio Programs. Reels, $1.00 Hour! Cassettes,
$2.00 Hour! ..Mammoth Catalog, $1.25. AM Treasures,
Box 192F, Babylon. N.Y. 11702.
65
$ 80
$ 65
$ 55
55
CD 4011
TAPE AND RECORDERS
-
$ 55
C002
J
RENT 4 -Track open reel tapes -all major labels -3,000
free brochure. Stereo -Parti, 55 St. James Drive,
different
Santa Rosa, Ca. 95401.
7447-1.15
92.60
7448-1.20
$1.75
7450- .18
... ,$1,75
7472- .40
-HI
5.95
7473- .43
91.25
7474- .43
$1.65
7475- .75
TRIACS
SCR'S
Similar to 8038C IC Voltage controlled oscillator, as featured in F737M11QLLF11$1.5a
Oct. 73P.E. they have sine, square niiRG1miZLQt1] , Ogrt1iw17
t t 111111110HII®MEINCIIi11ED7
and triangular outputs good to
MHz. Two of them can be used to laili1111114111101NIMUCCIPTIFIRI,
600
1.70 2.30 3.00
make an FM generator...$4.95
3.00
Send 20c for our catalog featurin
106
CHICAGO
$2.15
$3.50
Conductive Elastometer low
This board is
MCD -2 OPTO -ISOL
GREEN GAP OSL -16 LED
RED GAP OSL -3 LED
14 PIN DIP SOCKETS
16 PIN DIP SOCKETS
$2.75
DENVER
74C 157
74C 165
600
$4.75
$9.50
$1.75
Z,p
VANCOUVER
C/MOS (DIODE CLAMPED)
74C 02
5.55
74C 10
$ 60
MAN -1, RED OR YELLOW
LED READOUT S2.50
PRV
MAN -3 READOUT S $1.75 200
MAN -4 READOUTS
S 52.00 400
8223-PROGRAMMABLE
$5.95
S
5/$1.00
4/$1.00
20v 4.7UF TANT. 5/$1
12V IOUF ELECT. 5/$1
50V 1000F ELECT $.40
25V 30UF ELECT 411.00
1103 1024 bit RAM
NEC 6003 2048 bit RAM
1101 256 bit RAM
8225 64 bit-write RAM
$50
$50
FLV 100 VISIBLE LED
ME -4 IR LED
$ .60
$ .90
2N2218A NPN Si TO-5
2N4891 UJT
ER900 TRIGGER DIODES 4 /51.00
2N6027 PROG. UJT
$ 75
4
State
LOSANGUES TORONTO
SAN FRANCISCO
TEKTRONIX 321A
PORTABLE ALL -TRANSISTORIZED
3 ", 5MHz TRIGGERED SCOPES
3
City
FREE BROCHURE LISTING 1,000
CORPORATIONS which may be interested in your
invention. Many well -known manufacturers have engaged
us to locate new products. For Free brochure and
information regarding the promotion of your invention,
contact: Gilbert Adams Organization, Dept. 20L, 80 Wall
Street, New York, New York 10005.
INVENTORS! Don't sell or license your invention until you
receive our offer. Eagle Development Company, Dept. P11, 82 Wall Street, New York City 10005.
02143 TEL. (617) 547 -4005
e
Mass.
DEGREE IN ELECTRONICS through correspondence. Free
catalog. Grantham, 2000 Stoner Avenue, Los Angeles,
California 90025.
INTENSIVE 5 week course for Broadcast Engineers. F.C.C.
First Class license. Radio Engineering Incorporated, 52 S.
Palm Ave., Sarasota, Florida 33577.
SHORTCUTS To Success! Highly Effective, Profitable
Short Courses (75 Choices). Study At Home. Diploma
Awarded. Our 29th Year. Free Literature. CIEE-D, Box
20345, Jackson, Miss. 39209.
EXAM
F.C.C. MANUAL
-
PASS FCC EXAMSI M.moria., study "Tseh
Answers" for FCC 1N and 2nd ries Radio.
licornes. Needy r..ie.d multipl.dnoip quartions end dipnens cow. all aven
tested in FCC cesses plu. "Self-Study Ability
TM.phon
s
T.0." 09.96
pna
tpaid. Monyb.ek Gu.reuee.
COIMMAND PRODUCTIONS
RA010 IRtiRIIIINt 4n)S10u
SAN
P.O. BOX 26348 -P
FRANCISCO, CALIF. 94126
DEGREE Program in Electronics Engineering. Our 29th
Year! Free literature. Cook's Institute, Dept. 13, Box 20345,
Jackson, Miss. 39209.
DIG ITAL:THEORY,DESIGN
CONSTRUCTION
,
LOGIC
NEWSLETTER ©
SAMPLE COPY $ 1.00
LOGIC NEWSLETTER
POB 252
WALDWICK,N.J. 07463
CIRCLE NO. 35 ON READERS SERVICE CARD
POPULAR ELECTRONICS
Over 300 questions and
SCORE high on F.C.C. Exams
answers. Covers 3rd, 2nd, 1st and even Radar. Third and
Second Test, $14.50; First Class Test, $15.00. All tests.
$26.50. R.E.I., Inc., Box 806, Sarasota, Fla. 33577.
ALTAJ ELECTRONIC BARGAINS
LEARN design techniques. Electronics Monthly
Newsletter. Digital, linear construction projects, design
theory and procedures. Sample copy $1.00. Valley West.
Box 2119 -B, Sunnyvale, California 94087.
FCC LICENSE through tape recorded lessons. Also Radar
Endorsement. Radio License Training, 1060D Duncan.
Manhattan Beach, Calif. 90266.
LEARN ELECTRONICS at home. FCC license, Communications Electronics, Satellite Communications. Free
Catalog. Genn, 5540 Hollywood BV., Los Angeles, CA
90028.
MUSICAL INSTRUMENTS
30% DISCOUNT name brand musical instruments. Free
Catalog. Freeport Music, 455N, Route 110, Melville, N.Y
11746.
WHOLESALE! Professional Guitars, PA Systems, Altec
Speakers, 240W RMS Amplifiers. Free Catalog, Carvin,
Escondido, Calif. 92028.
30% + DISCOUNT. Name Brand Musical Instruments. Free
Catalog. Continental Music, Dept. H. P.O. Box 3001.
Garden City, New York 11530.
SPECIAL interest records available, produced by the
editors of the world's leading special interest magazines.
Send for free catalog. Record Catalog, CL, Ziff -Davis
Publishing Co., One Park Avenue, New York, N.V. 10016.
BUSINESS OPPORTUNITIES
MADE $40,000.00 Year by Mailorder! Helped others make
money! Free Proof. Torrey, Box 318 -NN, Ypsilanti,
I
Michigan 48197.
FREE CATALOGS. Repair air conditioning, refrigeration.
Tools, supplies, full instructions, Doolin, 2016 Canton.
Dallas, Texas 75201.
MAILORDER MILLIONAIRE helps beginners make $500
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PIANO TUNING LEARNED QUICKLY AT HOME'
Tremendous field! Musical knowledge unnecessary. Cl
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FREE Secret Book "2042 Unique Proven Enterprises."
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$178.00 WEEKLY. Work one hour daily. Free brochure.
FAS, Box 13703 -A, San Antonio TX, 78213.
CITIZENS BAND
rillih
DEALER -DISTRIBUTORS
CALCULATOR CHIP BONANZA!
THREE VERSIONS TO CHOOSE FROM
Never before offered in USA. These are the
newest and easiest to use chips available to
the hobbyist today. Features: direct segment
drive for LED's, low power consumption,
single supply voltage, internal encoding of
keyboard inputs, internal keyboard debounce,
internal clock oscillator. Made by famous US
mfg. No one but ALTAJ offers calculator
chips with these sophisticated functions. All
are 28 Pin DIP. with Specs. FLOATING DEC
P. O.
Box 778
Ca.
92683
EARN $15,000 annually plus. Full year trial plan Import -
Mailorder business. Postcard brings details: Northeast
Imports, Box 121PE10, Fremont, N.H. 03044.
HOW TO SELL BOOKS BY MAIL. FREE INFORMATION.
McCord, Box 276 -D, SYLVANIA, OHIO 43560.
$1,000 MONTH Mailorder. Send Stamp. Fiddes, Box 1242F,
Glen Burnie, MD 21061.
OPPORTUNITY PACKAGE! Three amazing business plans.
Free details; Gray Bros., 4830 SP. 137 St., Suite 72U-11
Omaha, Nebraska 68137.
-
EARN V8 500 WEEKLY
EASY!
OR MORE
-
FREE
SAMPLE 8
DETAILS
6T PRODUCTS. INC.,
See
II.$HK
Minim Gerp At
Diego. Gllf. 92120
6156
-8
-
$29.95 ea.
-
-
SALE!
FACTORY NEW LED'S
Jumbo Red -Like MV5024
-
-
8
for $1
5
Jumbo Green -Like MV5222
for $1
10 for
Mini Red -Like MV50
-
CHIP #3
8 DIGIT READOUT, MEMORY,
SIX FUNCTION ( +, -, x, =, %, 1 /x) - $8.95
$1
3 DIGIT LED READOUTS
Perfect for use with our calculator chips. 3
MAN -3 Readouts in one DIP. Properly multiplexed. New prime units. Like Litronix DL -33.
$1.25 ea. 3 for $2.95
OPCOA SLA -1 LED READOUT
.33 in. Character. Left DEC. point.
Uses 7447 driver. Easier to read than
MAN -1 types. Factory prime units
$1.19 ea.
PC BOARD SPECIAL #3
Boards from computer eqmt. with the following items:
-3.600 MHz Oscillator 5 VDC,
2- Monsanto MCT2 Opto Isolator, 4- 2N3642
Transistors, 1- 2N2646 Unijuction, 2 -7400,
DIGITAL ALARM CLOCK IC
Through a special arrangement with
a famous U.S. MFG. we can offer
these MOS chips. This is the newest
and easiest to use alarm chip on the
market today. Features: 1. Single
1
1
-7402,
1
-7404,
2
-7408,
1
-7410,
1
-7438,
7474, 2 -7476, 1 -7486, 3 -7490, 1 -7492,
3 -7493, 1- 74164, 1- 74165, 1- 74180, 1 -9601
Plus 17 other DIP IC's. Limited quantity.
$4.95
Special Price
1-
supply voltage
-
2.
3.
4.
5.
6.
-
JUMBO LED READOUT
.65 in. character. Twice the size of regular
readouts. Like Litronix DL747. Outperforms
SLA -3. Easy to read. Draws only 20 MA per
segment. Perfect for giant digital clocks.
$2.95 ea.
7
Ft. Black.
2
wire.
4
for
$1
HOBBYIST LINEAR SPECIAL
We bought too many too test. Includes many
useable devices. Buy untested and save.
LM380 2 watt audio AMP 8 for $1
LM3900 QUAD OP AMP 8 for $1
10 for $1
709C OP AMP
741C Mini DIP OP AMP 10 for $1
-
-
$7.95 ea.
FAIRCHILD STYLE VOLTAGE
REGULATORS
Your Choice
AMP Output
-
1
Ea.
7805
7806
7812
--
5VDC 7815
6VDC 7818
12VDC7824
CD4011
CD4013
---
--
44c
95c
-
$1.25
15VDC
18VDCTO -220
24VDC CASE
-C -MOS IC'S
RCA STYLE
44c
CD4001
44c
CD4002
CD4016
CD4020
CD4049
-C
740107
-
-
COMPARE THIS PRICE
WITH SPEC. SHEETS
---
NEW!
89c
1.49
49c
-MOS
7400 SERIES STYLE
1.25
74C83
74C04
49c
MINI CORE MEMORY SYSTEM
Mfg. by Dataram. Stores 180 words of 18 bits
each. With sense AMP's and associated
electronic drive circuits. A complete memory
system. We include 50 pages of data and
$24.95 Data
schematics. BRAND NEW
Only $2.50
MALLORY FILTER CAPS
2000MFD 30VDC
39c
Led intensity control
Simple time set
4 or 6 digit led display
AM -PM indication
24 hr alarm with 10 min.
snooze
7. Outperforms MM5316
REGULATED DC POWER SUPPLY
Brand new mfg. by WANLASS. Open Style.
DC Output 17 to 30 V. Rated 60 watts. Our
tests show these units will put out 12 VDC by
changing one resistor. Wanlass #OEM60-3.
Original cost $57.50. In original factory
boxes, with specs and schematic. Special
$19.95
-
-
-
95c
95c
LM 309K
1
AMP 5VDC TO -3 Voltage regulator new
by national. Prime units.
ALTAJ ELECTRONICS
P.O. BOX 38544
DALLAS, TEXAS 75238
TERMS: Check or M.O. No COD.
Add 10% for PSTG and HDLG. Tex.
SMALL SIZE
CIRCLE NO.
NOVEMBER 1974
recommended for experienced
hobbyists only. Limited quantity
CHIP #2
DIGIT READOUT, MEMORY, SIX
FUNCTION ( +, -, x, -e,y-,'K)
$8.95
Vinyl Repair Specialists /Dealers!
Sensational opportunity available! Operate your
own profitable business. Write today!
Now needed
Array is mounted on two stacked 6 x
8 in. PC boards. Original cost $300
ea. With schematic. These are
-
AC LINE CORDS
Westminster,
various transistors, diodes, etc.
8 DIGIT READOUT, CONSTANT,
CHIP #1
- $7.95
SIX FUNCTION ( +, -, x, =,
Send this Ad to:
PAL ELECTRONICS CO.
SOLID STATE MEMORY ARRAY
Brand new, MFG. by Monolithic
Systems Corp. Consists of 16 -1101
(256 Bit Ram) and associated drive
circuits. Drive circuits include 24
assorted 7400 series devices and
2
Res. Add 5%
ON READERS SERVICE CARD
107
EXCLUSIVE for readers o
STOP
Popular Electronics
DIGITALdescribed
CLOCK /CALENDAR KIT!!
at left.
FREE
With all the options
DISC CAPACITORS
Solid Slate Systems otters e complete selection of Permit Di. Capacitors fora wide range of gpliutione iron
nigh
age RF to lox voltage transistor CircUÍtry.PLEASE NOTE: In oraw m maintain our bw plcea, ww must
uenlMat you
in EXACT
of 10 per IMm; You melt
mid
velu.
quantity oricirg.
lia
tga0ters offer high woofs
minimum spine. All nor
capa
Sprague type 5116 ceramic
5 HK
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imra
5.
1:=
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Sang,
_1016. uBOX.
or
5GA
F:0aM 500WVOC
end including 'O
Gpeci-
72-10389
72.15360
72-203E9
1000 oF
1500 pF
2000 or
77-22389 1200
1430 3300
7147360 4700
]}501430 5000
10. 100 260- 500
09
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60
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71.50003
71.75069
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INTEGRATED
CIRCUITS
as
FREE with each order totaling $250.00 or more if
postmarked before December 1, 1974.
PLEASE ORDER BY CATALOG NUMBER
03 -12241
of
PRESS
71.33269
71.36269
08
p
10
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Dear Customer:
Are you confused with the wide range of prices
you see while reading through this or other
hobby magazines? Well, allow us to explain!
We at Solid State Systems are proud to offer
our customers ONLY factory FIRST -RUNS,
marked and identified with FULL manufacturer's name and part numbers. We have never
purchased a single "reject" or "seconds" unit.
The best we know, only one other hobby
supplier, also in Mid -West, has the same policy.
Most others usually buy below -spec, "functional only" units as scraps at a fraction of the
price and therefore are able to offer them at
lower prices.
The best test of this, is the fact that in the past
three years, we have never offered any "Didn't
have a chance to check them all" or "For
Experimenter's Only" items for sale in any of
our advertisements or Catalogs.
So, when shopping for parts, please remember:
Manufacturers test all their production units
and FACTORY TESTED is NOT the same as
FIRST RUN PRIME. Defective units were
tested too!
066
30
360 pF
1000
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73.50442
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QUAD 2 -INPUT POS. NAND GATE
QUAD 2-INPUT POS. NANO GATE WITH 0/C
QUAD 2-INPUT POS. NOR GATE
QUAD 2-INPUT P05. NAND GATE WITH 0/C
HEX INVERTER
HEX INVERTER WITH 0/C
QUAD 2 -INPUT PO5. AND GATE
QUAD 2 -INPUT P05. AND WITH 0/C
TRIPLE 3 -INPUT P05. NAND GATE
TRIPLE 3-INPUT POS. AND GATE
TRIPLE 3-INPUT POS. AND WITH 0/C
DUAL 4 -INPUT POS. NAND GATE
DUAL 4 -INPUT POS. AND GATE
DUAL 4 -INPUT POS. NAND WITH 0/C
DUAL 4 -INPUT POS. NAND BUFFER
EXP. DUAL 2 -WIDE 2-INPUT AND-OR-INVERT
DUAL 2-WIDE 2-INPUT AND -OR- INVERT
DUAL 4 -INPUT EXPANDER
4 -2-3 -2-INPUT AND-OR-INVERT GATE
4-2-3-2-INPUT AND -OR- INVERT WITH 0/C
DUAL J -K M -5 FLIP -FLOP
DUAL D-TYPE EDGE -TRIG. FLIP -FLOP
DUAL J -K M -S F -F W /PRESET & CLEAR
DUAL J -K M -5 F -F W/PRESET & CLEAR
DUAL J -K M-S FLIP-FLOP
DUAL J -K EDGE -TRIG. F -F W /SEP. CLK. & CLR.
DUAL J -K EDGE -TRIG. F -F W /SEP. CLOCK
DUAL J -K EDGE -TRIG. F -F W /COM. CLK. & CLR.
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55¢
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11-.00
BMW
All IC's re supplied in 8 -. 14 -, or 24 -pin DIP
(Dual -in Icel p antic or ce antic package esoso
-
Ior NE536. NE540, and S 540, which come iri
TO -5 package. Voltage Regulators SI 3554M,
SI 3120E, 513 50E. and 513240E are supplied
in TO- 31Diamondl package.
We give FREE data sheets Upon request, so ask
for those data sheets that you NEED, even for
those hated IC's Mal you are not buying.
60 ,54
SOLID 64Q4I
10s
1.06
'ce74xA
205 0.473 .079 .020
10
Color
0.33"
d1scorainuing our line of Schottky TTL's and, while the
quantities last, they are offered at our cost.
We regret therefore, that we cannot process back -orders for the
items
and proper credit will be issued for all items SOLD OUT.
Please note that Schottky's also have a Grouping Code of 1 and, while
there are no price breaks for them, they may be combined with your
other IC orders to take advantage of price breaks for standard TT L's and
Linears!
74500
.283 0.417
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SCHOTTKY TTL
af 10 years.
PLEASE NOTE:
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Height
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7496
74161
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guaranteed to
BRAND NEW, manufacturer's FIRST RUN, yet Menke to au huge purN0ing Power. we are .hie
to offer Mm to you e organ well below whet uthen charge far fallouts and reject,.
Grouping Cale for ell eigleye is 3103.
Prices good Mru OW:wnber 31. 1972
orf
74
44
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POPULAR ELECTRONICS
IF
YOU CAN SOLDER, YOU CAN
BUILD YOUR OWN
Clock/Calendar
SOLID STAVE 6ú6ÏL M O1CQ has available a
CLOCK /CALENDAR kit containing over 120 separate electrical
5,
components.
The clear, simplified instructions include step by
step construction procedures and ample illustrations
which will quickly take you through construction of
this versatile Clock /Calendar.
THE KIT FEATURES:
* DISPLAY
OF DATE WITH MONTH AND DAY displays month and day automatically, through
year, except for February 29.
* DISPLAY OF TIME ON 12 HOUR CYCLE - hours
and minutes displayed with A.M. and P.M.
indicators.
*A
24 HOUR ALARM OPTION - this also includes a
snooze button which delays alarm an additional 10
minutes.
PLEASE NOTE: These kits do not include cases.
* A
This kit when completed is a sophisticated device
which offers many additional features due to its
flexibility, here are two examples of what can be
done with this device:
* EASILY VISIBLE
1.You may set the timer to play your radio for 15
minutes at bedtime, then the alarm allows you the
option of waking up to the radio in the morning all
automatically.
9 HOUR 59 MINUTE TIMING OPTION - this
allows operation of any pluggable 600 watt, 120
volt, 5 amp, 60 Hz electrical device such as a radio,
room light, stereo or coffee pot.
SPERRY® DISPLAY - this
display is highly visible in a well lighted room.
An attractive case may be fabricated of wood,
plexiglas, metal or whatever you feel would make an
appropriate show -case for your finished kit.
TO
ORDER:
Order Number 01 -12241 - BASIC CLOCK
minute appliance timer option. Price
Order Number 02 -12241
r.
-
-
This kit does not include the 24 hour alarm option or the 9 hour 59
$49.95.
COMPLETE CLOCK - This kit includes all available options. Price
SEND YOUR ORDERS TO:
SOLID STATE SYTEMS, INC.
1-21-4-
Ï
2.You may set the alarm to later start an appliance
which will operate for the duration of the setting
on the timer.
rT
50111J
'J
P.
r___r
U
NOVEMBER 1974
1ñ1n J
,,-,
U
-'JLS.NU'J0
MC.
$65.00.
BANKAMERICAR
0. BOX 617
COLUMBIA, MISSOURI 65201
OR PHONE (TOLL FREE)
800- 325 -2983
800 -325 -2981
CIRCLE NO. 36 ON READERS SERVICE CARD
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109
FREE
IC
With Every $10 Order*
REDUCE YOUR PROJECT COSTS
MONEY -BACK GUARANTEE
24 -HOUR SHIPMENT
ALL TESTED AND GUARANTEED
NPN:
MPS6515 TYPE High -Gain Amplifier hFE 250
Assort. NPN GP TYPES, 2N3565, 2N3641, etc. (15)
PNP:
2N3638 TYPE Gen. Purpose Amp & Switch
2N4249 TYPE Low-Noise Audio Amp 10A to 50mA
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ELECTRONICS
CRAFT AUDIO
TRANSISTORS:
2N3563 TYPE RF Amp & OSC to 1 GHz (pl. 2N918)
2N3565 TYPE Gen. Purpose High Gain (TO -106)
2N3567 TYPE High- Current Amplifier /Sw 500mA
2N3691 TYPE GP Amp to 25mA and 50 MHz
2N3866 TYPE RF Pwr Amp 1 -2 W @ 100 -600 MHz
2N3903 TYPE GP Amp & Sw to 100mA and 30 MHz
2N3904 TYPE GP Amp & Sw to 100mA (T0-92)
2N3919 TYPE RF Pwr Amp 3 -5 W @ 3.30 MHz
2N4214 TYPE Ultra -High Speed Switch 12ns
-ABOUT
6/$1.00
6 /$1.00
3/$1.00
6/$1.00
$1.50
6/$1.00
5/$1.00
$3.00
4/$1.00
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4/51.00
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Box 30P , Swarthmore PA 19081
if
MOVIE FILMS
8MM -SUPER 8 -16MM MOVIES! Biggest Selection! Lowest
Prices! Free Catalog! Cinema Eight, Box PE, Chester,
Connecticut 06412.
FET's:
N- CHANNEL (LOW-NOISE):
2N4416 TYPE RF Amplifier to 450 MHz (TU -72)
2N5486 TYPE RF Amp to 450 MHz (plastic 2N4416)
2N5163 TYPE Gen. Purpose Amp & Sw (TO -106)
2N4091 TYPE RE Amp & Switch (TO-1061
E100 TYPE Low -Cost Audio Amplifier
ITE4868 TYPE Ultra -Low Noise Audio Amp.
TIS74 TYPE High-Speed Switch 4011
Assort. RF & GP FET's, 2N5163, 2N5486, etc. (81
P- CHANNEL
2N4360 TYPE Gen. Purpose Amp & Sw (TO-106)
E175 TYPE High-Speed Switch 1252
M104 TYPE MOS FET (Diode protected) 0.3 pF
EMPLOYMENT OPPORTUNITIES
2/$1.00
3/$1.00
3/51.00
3/$1.00
4/$1.00
2/51.00
3/$1.00
1
3/51.00
3 /$1.00
$3.00
$1.90
$1.50
$ .90
$ .39
$ .15
$1.00
S .45
$1.55
$1.25
S .95
$2.00
DIODES:
1N914 TYPE Gen. Purpose 100V /10mA
1 N3600 TYPE Hi Speed SW 75V /200mA
1 N4608 TYPE GP & SW 80V /400mA
1N3893 TYPE RECTIFIER Stud Mount 400 V /12 A
1N749 ZENER 4.3 Volt 400mW
1N753 ZENER 6.2 Volt 400mW
1N755 ZENER 7.5 Volt 400mW
1N757 ZENER 9.1 Volt 400mW
1 N758 ZENER 10
Volt 400mW
1N965 ZENER 15 Volt 400mW
1N968 ZENER 20 Volt 400mW
05 VARACTOR 5.50 W Output @ 30.250 MHz, 7-70 pF
F7 VARACTOR 1-3 W Output @ 100 -500 MHz, 5-30 pF
MAIL
10/$1.00
6/$1.00
6/$1.00
2/$1.00
3/$1.00
4/$1.00
4/11.00
4/$1.00
4/11.00
4/$1.00
4/$1.00
$5.00
$1.00
NOW! With every order of $10 or more, postmarked
OP AMP
prior to 12/31/74. FREE 739 or 749 Low -Noise Dual
included -$1 VALUE.
ORDER TODAY-All items subject to prior sale and prices subject
to change without notice. DATA SHEETS included with all items.
WRITE
FOR FREE
CATALOG offering hundreds of semiconductors not listed here. Send 100 stamp.
TERMS: All orders prepaid. We pay postage. $1.00 handling
charge on orders under $10. Calif. residents add 6% sales tax.
ADVA
New York 11768.
$2.00
LINEAR IC's:
309K Voltage Regulator 5V @ lA (T0.3)
380 2 -5 Watt Audio Amplifier 34dB (DIP)
555X Timer l0-1 hr, Dif. pinout from 555 (DIP)
709 Popular OP AMP (OIP/T0-5)
723 Voltage Regulator 3 -30 V @ 1.250mA (DIP/T0 -5)
739 Dual Low -Noise Audio Preamp /OP AMP (DIP)
741 Freq. Compensated OP AMP (DIP/TO- 5 /MINIOIP)
2556 Dual 555 Timer 1 usec to hour (DIP)
LM305 Positive Voltage Regulator (T0-5)
MC1458 Dual 741 OP AMP (MINI -DIP)
Assorted Linears -741 /709/723, etc. (4)
ELECTRONICS/AVIONICS EMPLOYMENT OPPORTUNITIES. Report on jobs now open. Details FREE. Aviation
Employment Information Service, Box 4240E, Northport,
EMPLOYMENT INFORMATION
JOBS, Electronic Technicans, EE's, Tech Reps. Address
100 companies. US and overseas. Send $2.00. Marshburn,
Box 655, Wylie, Texas 75098.
REAL ESTATE
... FREE _..CATALOG! 272 pages! Over 2,500 top
values in FARMS, RANCHES, ACREAGES,
BIG
RECREATIONAL PROPERTIES, BUSINESSES, TOWN and
COUNTRY HOMES in 40 states coast to coast! Over 3,800
PHOTOS! UNITED FARM AGENCY, 612 -EP West 47th St.,
Kansas City, MO 64112.
RECORDS
OLDIES. 45rpm. Free Catalog. Corny's Record Shop, Box
335TP, Mason, Ohio 45040.
RUBBER STAMPS
RUBBER address stamps. Free catalog. 45 type styles.
Jackson's, Box 443G, Franklin Park, II!. 60131.
MAGNETS
MAGNETS. All types. Specials -20 disc, or 10 bar, or 2 stick,
or 8 assorted magnets, $1.00. Magnets, Box 192 -H,
Randallstown, Maryland 21133.
DO -IT- YOURSELF
ELECTRONICS
BOX 4181 -J, WOODSIDE, CA 94062
Tel. (415) 851 -0455
CIRCLE NO. 1 ON READERS SERVICE CARD
"*.t.thea p
FREE WINDPOWER HEAT Cuts fuel bills, beats shortages.
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from Energy Unlimited, Dept. 611, 219 Thorndike Street,
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,cAFFIX LABEL-
03
Ó)
vc
-
N
TREASURE FINDERS
m
CO
s
V1
PLASTICS
FAMILY FUN! OUTDOOR ADVENTURE! Find valuable
coins and treasure with world famous metal detectors. Free
illustrated booklet. Detectron, Dept. PE, Box 243, San
Gabriel, Calif. 91778.
TREASURE FINDER locates burled gold, silver, coins.
treasures. 5 powerful models. $19.95 up. Instant financing
available. Free catalog. Dealer inquiries invited. Relco,
Dept. A -33, Box 10839, Houston, Texas 77018.
ELECTRICAL SUPPLIES & EQUIPMENT
Equipment, Portable Platers, Supplies and
"Know- How." Build your own tanks for nickel, chrome,
etc. Easy -to- install PVC liners. Rectifier components -all
PLATING
CASTOLITE pours like water, hardens like glass without
heat. Crystal clear, colors. Embed flowers, seashells,
mementos, anything. Make fine gifts. Form flexible molds
over any pattern, size. Reproduce your own designs in
plastics, candlewax, metal, plaster, cement. Send 50 cents
for illustrated Manual and New Mold Catalog. Profitable.
CASTOLITE, Dept. 74M /PE, Woodstock, III. 60098.
HYPNOTISM
SLEEP learning. Hypnotic method. 92% effective. Details
free. ASR Foundation, Box 23429EG, Fort Lauderdale,
sizes. Schematics, parts lists, formulas, operating
instructions for all plating. Guaranteed to save you 25%75%. Some good units for sale. Write for details. Platers
Service Company, 1511 -PE Esperanza, Los Angeles, Calif.
Florida 33307.
FREE Hypnotism. Self- Hypnosis. Sleep Learning Catalog!
Drawer H400, Ruidoso, New Mexico 88345.
AMAZING self- hypnosis record releases fantastic mental
power. Instant results! Free trial. Write: Forum (ÁA11), 333
90023.
North Michigan, Chicago 60601.
110
J
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ó
.d
se
ñ
v
a
a
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ó
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ä
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e aal_+` _J
-o
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-
Add'I postage: $2 per year outside U.S., its poss. & Can.
POPULAR ELECTRONICS
Quality
Popular Electronics
Electronic Components
HOME ENTERTAINMENT FILMS
MINIATURE ALUMINUM
- -
make
COLOR ACTION SPORTS FILMS (Also B &W)
a
great gifts in Super 8 and Standard 8. Treat yourself
friend. In color, $16.95 each plus 50 cents postage; $7.95
plus 50 cents B &W for 200' reel. Select from Columbia.
Castle and Sportlite Catalogs at 25 cents each (stamps or
coins, please). Be on time for Christmas, send your
quarters today. SPORTLITE, Elect -11 Dept., 20 North
Wacker Drive, Chicago, Illinois 60606.
NOVEMBER 1974
ADVERTISERS INDEX
110
Adva Electronics
1
2
44
Allied Electronics
91
Alpha Electronics
Altaj Electronics
Ancrona Corp
Audioanalyist, Inc
26
107
13
71
3
Audio -Technica U.S., Inc
6
B &K Products of Dynascan
18
CREI
Institute
8
9
10
Cliiford's
Hi -Fi
Cobra Product of Dynascan Corporation
102
11
Delta Electronics Co
12
Delta Products, Inc
13
Digi -Key Corporation
14
EICO
15
Edmund Scientific Co
105
16
Edmund Scientific Co
112
89
98
17
Electronics
GTE Sylvania
18
Great American Sound Company, Inc., The
19
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THIRD COVER
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106
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Southwest Technical Products Corp
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Tracy Design Corporation
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SECOND COVER,
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NOVEMBER 1974
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Why you should select your turntable
more carefully than any other component.
Every component is important to the total
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In time, your changing tastes can outgrow your
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accJrately a. ..v perfe :t
balance can turn the style, into a
destructive instrument ec -.ily
capable of lopping off the sharp
contours which carry the - igh
frequencies. When that
happens, the clean high notes
become fuzzy memories.
Permanently. There's just no
way to restore a damaged
record. Even the
a.---best equipment a .can't replace
notes once
they're gone.
:_
I
I
"
you should consider what you require of operating
convenience and flexibility. For example, ìt you don't
relish risking your stylus and records by handling the
tonearm each time you play a record, you will want
an automatic turntable. And if you desire to play
two or more records in sequence, you will want a
turntable with record changing ability.
All Dual turntables easily =ulfill every
réguirernent for record playback and preservation
-and every requirement for er convenience.
Which is why the reacers of the leading
audio and music magazines own more
Duals than a.ny other turntcble. It's
also why so many audio professionals
are quite satisfied with even the
lowest- p-iced Dual.
Please wr to for our
very informative arochures
and complete r prints of
independent test reports.
The more car ?Jul iy you
read them, tine more
likely you -e to
select a
Any Duc
After
Dual
considering
what your
records
require for
longevity,
United Audio Products
12 J So. Colum DJs Ave.,
M -. Vernon, N.Y. 10553
Exclusive Distr'bution Açency for Dual
From front to rear Dud41229t
5259.95; Dual 1728, $11395; Dual 1226, $159.95: Dual 1225, $12995.
CIRCLE NO. 4 ON READERS SERVICE CARD