LCR Primer (Quadtech) - Kripton2035 Electronic and Fun Web

5 Clock Tower Place, 210 East, Maynard Massachusetts 01754
TELE: (800) 253-1230, FAX: (978) 461-4295, INTL: (978) 461-2100
http://www.quadtech.com
2
Preface
The intent of this reference primer is to explain the basic definitions and
measurement of impedance parameters, also known as LCR. This primer
provides a general overview of the impedance characteristics of an AC circuit, mathematical equations, connection methods to the device under test
and methods used by measuring instruments to precisely characterize
impedance. Inductance, capacitance and resistance measuring techniques associated with passive component testing are presented as well.
LCR Measurement Primer
4th Edition, February 2005
Comments: info@quadtech.com
5 Clock Tower Place, 210 East
Maynard, Massachusetts 01754
Tel: (978) 461-2100
Fax: (978) 461-4295
Intl: (800) 253-1230
Web: http://www.quadtech.com
This material is for informational purposes only and is subject to change
without notice. QuadTech assumes no responsibility for any error or for
consequential damages that may result from the misinterpretation of any
procedures in this publication.
3
Contents
Impedance
Definitions
Impedance Terms
Phase Diagrams
Series and Parallel
Connection Methods
5
5
6
7
7
10
Two-Terminal Measurements
Four-Terminal Measurements
Three-Terminal (Guarded)
10
10
11
Impedance Measuring Instruments
12
Methods
Functions
Test Voltage
Ranging
Integration Time
Median Mode
Computer Interface
Test Fixtures and Cables
Compensation
Open/Short
Load Correction
Capacitance Measurements
Series or Parallel
High & Low Value Capacitance
ESR
Inductance Measurements
Series or Parallel
Inductance Measurement Factors
DC Bias Voltage
Constant Voltage (Leveling)
Constant Source Impedance
DC Resistance and Loss
Resistance Measurements
Series or Parallel
Precision Impedance Measurements
Measurement Capability
Instrument Accuracy
Factors Affecting Accuracy
Example Accuracy Formula
Materials Measurement
Definitions
Measurement Methods, Solids
Contacting Electrode
Air-Gap
Two Fluid
Measurement Method, Liquids
Recommended LCR Meter Features
12
13
13
14
14
14
14
15
15
15
16
17
17
18
20
21
21
21
22
22
22
23
24
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25
25
26
27
28
30
30
30
30
31
32
33
4
34
Test Frequency
Test Voltage
Accuracy/Speed
Measurement Parameters
Ranging
Averaging
Median Mode
Computer Interface
Display
Binning
Test Sequencing
Parameter Sweep
Bias Voltage and Bias Current
Constant Source Impedance
Monitoring DUT Voltage and Current
34
34
34
34
34
34
34
35
35
36
37
37
37
37
38
Examples of High Performance Testers
Digibridge ® Component Testers
1600 Series
1659
1689/89M
1692
1693
1700 Series
1715
1730
Precision LCR Meters
1900 Series
1910 Inductance Analyzer
1920 LCR Meter
7000 Series
7400 LCR Meter
7600 LCR Meter
Dedicated Function Test Instruments
Milliohmmeters
Megohmmeters
Hipot Testers
Electrical Safety Analyzers
39
39
39
39
39
39
39
40
40
40
41
41
41
41
41
42
42
42
42
42
42
42
Appendix A
Nationally Recognized Testing Laboratories
(NRTLs) and Standards Organizations
Helpful Links
Typical Measurement Parameters
Impedance Terms and Equations
LCR Selection Guide
LCR Accessory Selection Guide
43
Application Note Directory
51
Glossary
55
44
45
46
47
48
50
Impedance
Impedance
Complex Quantity
However, if capacitance or inductance are present, they also affect the flow of current. The
capacitance or inductance cause the voltage
and current to be out of phase. Therefore,
Ohms law must be modified by substituting
impedance (Z) for resistance. Thus for ac,
Ohm's Law becomes : Z = V/I. Z is a complex
number: Z = R + jX . A complex number or
quantity has a real component (R) and an imaginary component (jX).
Impedance is the basic electrical parameter
used to characterize electronic circuits, components, and materials. It is defined as the ratio
of the voltage applied to the device and the
resulting current through it. To put this another
way, impedance is the total opposition a circuit
offers to the flow of an alternating current (ac)
at a given frequency, and is generally represented as a complex quantity, which can be
shown graphically. The basic elements that
make up electrical impedances are inductance,
capacitance and resistance: L, C, and R,
respectively.
In the real world electronic components are not
pure resistors, inductors or capacitors, but a
combination of all three. Today's generation of
LCR meters are capable of displaying these
parameters and can easily calculate and display many other parameters such as Z, Y, X, G,
B, D, etc. This primer is intended as an aid in
understanding which ac impedance measurements are typically used and other factors that
need to be considered to obtain accurate and
meaningful impedance measurements.
Phase Shift
The phase shift can be drawn in a vector diagram which shows the impedance Z, its real
part Rs, its imaginary part jXs (reactance), and
the phase angle θ. Because series impedances add, an equivalent circuit for an impedance would put Rs and Xs is series hence subscript ‘s’. The reciprocal of Z is Admittance, Y
which is also a complex number having a real
part Gp (conductance) and an imaginary part
jBp (susceptance) with a phase angle φ. Note
θ = - φ. Because admittances in parallel add,
an equivalent circuit for an admittance would
put Gp and Bp in parallel. Note from the formulas below that, in general, Gp does not
equal (1/Rs) and Bp does not equal -(1/Xs).
Definitions
The mathematical definition of resistance for dc
(constant voltage) is the ratio of applied voltage
V to resulting current I. This is Ohms Law: R =
V/I. An alternating or ac voltage is one that
regularly reverses its direction or polarity. If an
ac voltage is applied to a circuit containing only
resistance, the circuit resistance is determined
from Ohms Law.
For DC, Resistance, R =
Refer to Table 1 for Impedance terms, units of
measure and equations.
V
For AC, Impedance, Z =
I
5
V
I
= R + jX
Table 1: Impedance Terms & Equations
Parameter
Z
Quantity
Impedance
Unit Symbol
ohm, Ω
|Z|
Magnitude of Z
ohm, Ω
Rs or ESR
Resistance,
Real part of Z
ohm, Ω
Xs
Reactance,
Imaginary part of Z
ohm, Ω
Y
Admittance
siemen, S
|Y|
Magnitude of Y
siemen, S
(was mho)
GP
Real part of Y
siemen, S
BP
Susceptance
siemen, S
Formula
1
=| Z | ε
Y
1
| Z |= R S 2 + X S 2 =
|Y |
G
RP
RS = 2 P 2 =
1 + Q2
GP + B P
Z = R S + jX S =
XS =−
jθ
BP
G P + BP
1
Y = GP + jB P = =| Y | ε jφ
Z
1
| Y |= G P 2 + B P 2 =
|Z|
R
GP = 2 S 2
RS + X S
BP = −
Cs
Series capacitance
farad, F
CP
Parallel capacitance
farad, F
Ls
Series inductance
henry, H
LP
Parallel inductance
henry, H
RP
Parallel resistance
ohm, Ω
Q
Quality factor
none
D, DF or
tan δ
Dissipation factor
none
θ
Phase angle of Z
degree or radian
θ = −φ
φ
Phase angle of Y
degree or radian
φ = −θ
CS = −
2
2
XS
RS + X S
2
2
1
= C P (1 + D 2 )
ωX S
CP =
CS
B
=
ω 1+ D 2
LS =
X
Q2
= Lp
ω
1 + Q2
1
1
= L S (1 + 2 )
ωB P
Q
1
RP =
= R S (1 + Q 2 )
GP
LP = −
Q=−
1 X S BP
=
=
= tan θ
D RS GP
D=−
R
G
1
= S = P = tan(900 − θ ) = tan δ
Q X S BP
Notes:
1. f = frequency in Hertz; j = square root (-1); ω = 2πf
2. R and X are equivalent series quantities unless otherwise defined. G and B are equivalent parallel quantities unless otherwise defined.
Parallel R (Rp) is sometimes used but parallel X (Xp) is rarely used and series G (Gs) and series B (Bs) are very rarely used.
3. C and L each have two values, series and parallel. If no subscript is defined, usually series configuration is implied, but not necessarily, especially for C
(Cp is common, Lp is less used).
4. Q is positive if it is inductive, negative if it is capacitive. D is positive if it is capacitive. Thus D = -1/Q.
5. Tan δ is used by some (especially in Europe) instead of D. tan δ = D.
6
+jX
1
-j
ωCS
δ
RS
θ
+jX
+jB
+R
jωLs
-jX
-jX
RS
-j
δ
θ
RS
+R
θ
GP
-jB
1
ωLP
δ
θ
+G
+G
Y
-jB
RS
CP
CS
RP
or
GP
LS
IMPEDANCE
Capacitive
GP
Y
jωCp
δ
Z
+jB
Z
LP
RP
or
GP
ADMITTANCE
Inductive
Capacitive
Inductive
Figure 1: Phase Diagrams
Series and Parallel
itor or inductor. This is the series equivalent circuit of an impedance comprising an equivalent
series resistance and an equivalent series
capacitance or inductance (refer to Figure 1).
Using the subscript s for series, we have equation 1:
At any specific frequency an impedance may
be represented by either a series or a parallel
combination of an ideal resistive element and
an ideal reactive element which is either capacitive or inductive. Such a representation is
called an equivalent circuit and illustrated in
Figure 1.
The values of these elements or parameters
depend on which representation is used, series
or parallel, except when the impedance is purely resistive or purely reactive. In such cases
only one element is necessary and the series or
parallel values are the same.
Since the impedance of two devices in series is
the sum of their separate impedances, we can
think of an impedance as being the series combination of an ideal resistor and an ideal capac-
1:
Z = Rs + jXs
= Rs + j ωL = Rs -
j
ωC
For a complicated network having many components, it is obvious that the element values of
the equivalent circuit will change as the frequency is changed. This is also true of the values of both the elements of the equivalent circuit of a single, actual component, although the
changes may be very small.
7
Admittance, Y, is the reciprocal of impedance
as shown in equation 2:
2:
Y=
Gp, Cp and Lp are the equivalent parallel
parameters. Since a pure resistance is the
reciprocal of a pure conductance and has the
same symbol, we can use Rp instead of Gp for
the resistor symbols in Figure 1, noting that Rp
= 1/Gp and Rp is the equivalent parallel resistance. (By analogy, the reciprocal of the series
resistance, Rs, is series conductance, Gs, but
this quantity is rarely used).
Two other quantities, D and Q, are useful, not
only to simplify the conversion formulas of
Table 1, but also by themselves, as measures
of the "purity" of a component, that is, how
close it is to being ideal or containing only
resistance or reactance. D, the dissipation factor, is the ratio of the real part of impedance, or
admittance, to the imaginary part. Q, the quality factor, is the reciprocal of this ratio as illustrated in equation 5.
1
Z
It too is complex, having a real part, the ac conductance G, and an imaginary part, the susceptance B. Because the admittances of parallel
elements are additive, Y can be represented by
a parallel combination of an ideal conductance
and a susceptance, where the latter is either an
ideal capacitance or an ideal inductance (refer
to Figure 1). Using the subscript p for parallel
elements, we have equation 3:
3:
Y = Gp + jBp = Gp + j ωCp = Gp -
j
ωL
Note that an inductance susceptance is negative and also note the similarity or duality of this
last equation and Equation 1.
It is important to recognize that, in general, Gp
is not equal to 1/Rs and Bp is not equal to 1/Xs
(or -1/Xs) as one can see from the calculation in
equation 4.
4:
Y=
=
=
1
Z
=
5:
Rs + jXs
Rs
Rs + Xs2
j
Rs
Xs
=
Gp
Bp
=
1
Q
A low D value, or high Q, means that a capacitor or inductor is quite pure, while a low Q, or
high D, means that a resistor is nearly pure. In
Europe, the symbol used to represent the dissipation factor of a component is the tangent of
the angle delta, or tan δ. Refer to Table 1.
Some conventions are necessary as to the
signs of D or Q. For capacitors and inductors,
D and Q are considered to be positive as long
as the real part of Z or Y is positive, as it will be
for passive components. (Note, however, that
transfer impedance of passive networks can
exhibit negative real parts). For resistors, a
common convention is to consider Q to be positive if the component is inductive (having a
positive reactance), and to be negative if it is
capacitive (having a negative reactance).
1
2
D=
Xs
Rs + Xs2
2
Gp + jBp
Thus Gp = 1/Rs only if Xs = 0, which is the case
only if the impedance is a pure resistance, and
Bp = -1/Xs (note the minus sign) only if Rs = 0,
that is, the impedance is a pure capacitance or
inductance.
8
Formulas for D and Q in terms of the series and
parallel parameters are given in Table 1. Note
that the D or Q of an impedance is independent
of the configuration of the equivalent circuit
used to represent it.
It should be emphasized that these series and
parallel equivalent circuits both have the same
value of complex impedance at a single frequency, but at any other frequency their impedances will be different. An example is illustrated
in Figure 2.
Series
Parallel
1k Ω
0.05uF
2kΩ
DUT
Y
Z DUT = 1000 -j1000 Ω at 1.5915kHz
0.1uF
+jX
δ
-j
1kΩ
θ
+jB
+R
ω = 2π f
jω 0.05uF
1
ω0.1uF
δ
-jX
Z
-jB
f = 10/2π kHz = 1.5915kHz
ω = 2π (10/2π) kHz
θ
+G
2k Ω
Figure 2: Complex Impedance
9
ω = 10 kHz
Connection Methods
Connection to the device under test (DUT) is
crucial in determining the most accurate value
of the DUT’s impedance. The use of multiple
connections can reduce or remove impedance
measurement errors caused by series impedance in the connections or shunt impedance
across the unknown. Refer to QuadTech application note 035027 for an excellent tutorial on
Multi-Terminal Impedance Measurements. For
the discussion in this primer we will illustrate 2,
3 and 4-terminal connection methods. Note:
1- terminal = 1 wire = 1 lead = 1 connection.
typical impedance measurement range for a
two-terminal connection is limited to 100Ω to
10kΩ.
Four-Terminal Measurements
First let's jump into four-terminal measurements, which are simpler to explain and more
commonly used than a three-terminal measurement. With a second pair of terminals available, one can measure voltage across the
device with one pair and apply current to the
device with the other pair. This simple improvement of independent leads for voltage and current effectively removes the series inductance
and resistance error factor (including contact
resistance) and the stray capacitance factor
discussed with two-terminal measurements.
Accuracy for the lower impedance measurement range is now substantially improved down
to 1Ω and below. There will be some mutual
inductance between the current leads and voltmeter leads which will introduce some error, but
much of this is eliminated by using shielded
coaxial cabling. The most famous use of the
four-terminal connection is the Kelvin Bridge
which has been widely used for precision DC
resistance measurements.
This circuitry associated Lord Kelvin's name so
closely with the four-terminal connection technique that "Kelvin" is commonly used to
describe this connection.
Two-Terminal Measurements
The impedance of a device is defined by Ohm's
Law as the ratio of the voltage across it to the
current through it. This requires at least two
connections and therefore the arithmetic of terminals starts with two. With only two terminals,
the same terminals must be used for both
applying a current and measuring a voltage as
illustrated in Figure 3.
QuadTech
7600 PRECISION
LCR METER
!
IL
IH
PL
PH
Z
QuadTech
7600 PRECISION
LCR METER
!
Figure 3: Two Terminal Measurement
When a device is measured in this way it might
not be an accurate measurement. There are
two types of errors and these are the errors that
measurements with more connections will
avoid, one is the lead inductance and lead
resistance in series with the device and the
other is stray capacitance between the two
leads, both of which affect the measurement
results. Because of these error sources, the
IL
IH
PL
PH
Z
Figure 4: Four Terminal
10
QuadTech
7600 PRECISION
LCR METER
ments are simply called guarded measurements. They are also called direct impedance
measurements. Figure 6 illustrates one representation of a passive 3-terminal network.
The impedance Zx is that impedance directly
between points A and B. As shown by equation
6, errors caused by Za and Zb have been
changed. If it were not for the series impedances, the effect of Za and Zb would have been
removed completely. The combination of series
impedance and shunt impedance has given us
two new types of errors. We'll call the first
(z1/Za and z3/Zb) the "series/shunt" error. It's
caused by a voltage, or current, divider effect.
The voltage between point A and guard is
reduced because the attentuating or dividing
effect of the impedances z1 and Za. Likewise,
Zb and z3 divide the current Ix so that it doesn't
all flow in the ammeter. Note that this error is a
constant percent error, independent of the
value of Zx. It usually is very small at low frequencies unless the series and shunt impedances are actual circuit components as they
might be in in-circuit measurements.
A three-terminal connection usually employs
two coaxial cables, where the outer shields are
connected to the guard terminal of the LCR
meter. The guard terminal is electrically different from the instrument ground terminal which
is connected to chassis ground. Measurement
accuracy is usually improved for higher impedances, but not lower because lead inductance
and resistance are still present.
!
IL
IH
PL
PH
Za
Zb
Z
Figure 5: 7600 3-Terminal Kelvin
Three-Terminal (or Guarded)
Measurements
While the four-terminal measurement applies a
current and measures the resulting open-circuit
voltage, the three -terminal measurement does
the opposite, it applies a voltage and measures
the short circuit current. The extra terminal, or
third terminal, is called the guard. Any components shunting the unknown can effectively be
removed by connecting some point along the
shunt to this guard terminal.
The effect of any stray path, capacitive or conductive, (shunting Zx) can be removed by intercepting it with a shield tied to the guard point.
Likewise, "shunting Zx" can effectively be
removed in a series string of actual components by connecting some point along the string
to the guard and making a three-terminal measurement. Sometimes three-terminal measureFigure 6:
Three-Terminal Guarded
z1
using Delta Impedance Configuration
Zm =
V
I
= Zx 1 +
A
Equation 6:
formula for Figure 6
z1 + z 3
+
Zx
z1
Za
+
z3
Zb
z3
V
Za
C
z5
z5 Z x
Za Zb
11
B
Zx
Zb
A
Impedance Measuring Instruments
Digital LCR meters rely on a measurement
process of measuring the current flowing
through the device under test (DUT), the voltage across the DUT and the phase angle
between the measured V and I. From these
three measurements, all impedance parameters can then be calculated. A typical LCR
meter has four terminals labeled IH, IL, PH and
PL. The IH/IL pair is for the generator and current measurement and the PH/PL pair is for the
voltage measurement.
Most recently instruments have been developed which employ elaborate software-driven
control and signal processing techniques. For
example, the QuadTech 7000 LCR Meter uses
a principle of measurement which differs significantly from that employed by the traditional
measuring instruments. In particular, the 7000
uses digital techniques for signal generation
and detection. In the elementary measurement
circuit as shown in Figure 8, both the voltage
across the device under test (Zx) and the voltage across a reference resistor (Rs) are measured, which essentially carry the same current.
The voltage across Zx is Vx and the voltage
across Rs is Vs. Both voltages are simultaneously sampled many times per cycle of the
applied sine wave excitation. In the case of the
7000, there are four reference resistors. The
one used for a particular measurement is the
optimal resistor for the device under test, frequency, and amplitude of the applied ac signal.
For both Vx and Vs a real and imaginary (in
phase and quadrature) component are computed mathematically from the individual sample
measurements.
The real and imaginary components of Vx and
Vs are by themselves meaningless.
Differences in the voltage and current detection
and measurement process are corrected via
software using calibration data. The real and
imaginary components of Vx (Vxr and Vxi) are
combined with the real and imaginary components of Vs (Vsr and Vsi) and the known characteristics of the reference resistor to determine
the apparent impedance of the complex impedance of Zx using complex arithmetic.
Methods
There are many different methods and techniques for measuring impedance. The most
familiar is the nulling type bridge method illustrated in Figure 7. When no current flows
through the detector (D), the value of the
unknown impedance Zx can be obtained by the
relationship of the other bridge elements,
shown in equation 7.
7:
Zx =
Z1
Z2
Z3
Z1
ZX
D
Detector
Z2
Z3
Oscillator
Figure 7: Bridge Method
Various types of bridge circuits, employing combinations of L, C, and R as bridge elements, are
used in different instruments for varying applications.
12
IH
PH
IH
IX
PH
ZX
IL
K
VX
PL
VX
ZX
Differential
Amplifiers
PL
K
RS
VS
VS
IL
RS
-
ZX =
V X (RS )
+
VS
VX
=
VS
VS
ZX
RS
7000 Measurement Circuit, Simplified
7000 Measurement Circuit, Active 5-Terminal
Figure 8: 7000 Measurement Circuit
A source resistance (Rs, internal to the meter)
is effectively connected in series with the ac
output and there is a voltage drop across this
resistor. When a test device is connected, the
voltage applied to the device depends on the
value of the source resistor (Rs) and the impedance value of the device.
Figure 10 illustrates the factors of constant
source impedance, where the programmed
voltage is 1V but the voltage to the test device
is 0.5V.
Some LCR meters, such as the QuadTech
1900 have a voltage leveling function, where
the voltage to the device is monitored and
maintained at the programmed level.
Figure 9: QuadTech 7600 LCR Meter
Functions
The demand on component testing is much
more than a resistance, capacitance or inductance value at a given test frequency and stimulus voltage. Impedance meters must go
beyond this with the flexibility to provide multiparameters over wide frequency and voltage
ranges. Additionally, an easily understood display of test results and the ability to access and
use these results has become increasingly
important.
1910 Source Resistance
RS =25Ω
V PROGRAM
VP = 1V
Test Voltage
The ac output of most LCR meters can be programmed to select the signal level applied to
the DUT. Generally, the programmed level is
obtained under an open circuit condition.
VM= VP
Z X= R+jX
R = 25Ω
X = 0Ω
VM= ?
R2+ X2
(RS + R)2 + X2
DUT
V MEASURE
I MEASURE
Figure 10: Source Impedance Factors
13
Ranging
tion. In median mode 3 measurements are
made and two thrown away (the lowest and the
highest value). The remaining value then represents the measured value for that particular
test. Median mode will increase test time by a
factor of 3.
In order to measure both low and high impedance values measuring instrument must have
several measurement ranges. Ranging is usually done automatically and selected depending
on the impedance of the test device. Range
changes are accomplished by switching range
resistors and the gain of detector circuits. This
helps maintain the maximum signal level and
highest signal-to-noise ratio for best measurement accuracy. The idea is to keep the measured impedance close to full scale for any given
range, again, for best accuracy.
Range holding, rather than autoranging, is a
feature sometimes used in specific applications. For example, when repetitive testing of
similar value components, range holding can
reduce test time. Another use of range hold
occurs when measuring components whose
value falls within the overlap area of two adjacent ranges, where if allowed to autorange the
instrument’s display can sometimes change
resulting in operator confusion.
Computer Interface
Many testers today must be equipped with
some type of standard data communication
interface for connection to remote data processing, computer or remote control. For an
operation retrieving only pass/fail results the
Programmable Logic Control (PLC) is often
adequate, but for data logging it's a different
story. The typical interface for this is the IEEE488 general purpose interface bus or the RS232 serial communication line.
These interfaces are commonly used for monitoring trends and process control in a component manufacturing area or in an environment
where archiving data for future reference is
required. For example when testing 10% components, the yield is fine when components test
at 8% or 9%, but it does not take much of a shift
for the yield to plummet. The whole idea of production monitoring is to reduce yield risks and
be able to correct the process quickly if needed.
An LCR Meter with remote interface capability
has become standard in many test applications
where data logging or remote control have
become commonplace.
Integration Time
The length of time that an LCR meter spends
integrating analog voltages during the process
of data acquisition can have an important effect
on the measurement results. If integration
occurs over more cycles of the test signal the
measurement time will be longer, but the accuracy will be enhanced. This measurement time
is usually operator controlled by selecting a
FAST or SLOW mode, SLOW resulting in
improved accuracy. To improve repeatibility, try
the measurement averaging function. In averaging mode multiple measurements are made
and the average of these is calculated for the
end result. All of this is a way of reducing
unwanted signals and effects of unwanted
noise, but does require a sacrifice of time.
Median Mode
A further improvement of repeatability can be
obtained by employing the median mode func-
Figure 11: 7000 Series Computer Application
14
Test Fixtures and Cables
Open/Short
Test fixtures (fixturing) and cables are vital components of your test setup and in turn play an
important role in the accuracy of your impedance measurements. Consider these factors
pertaining to test fixtures and cables.
Open/Short correction is the most popular compensation technique used in most LCR instruments today. When the unknown terminals are
open the stray admittance (Yopen) is measured. When the unknown terminals are shorted
the residual impedance (Zshort) is measured.
When the device is measured, these two residuals are used to calculate the actual impedance
of the device under test.
When performing an OPEN measurement it is
important to keep the distance between the
unknown terminal the same as they are when
attached to the device. It's equally important to
make sure that one doesn't touch or move their
hands near the terminals. When performing a
SHORT measurement a shorting device (shorting bar or highly conductive wire) is connected
between the terminals. For very low impedance measurements it is best to connect the
unknown terminals directly together.
Compensation
Compensation reduces the effects from error
sources existing between the device under test
and the calibrated connection to the measuring
instrument. The calibrated connection is determined by the instrument manufacturer, which
can be front or rear panel connections, or at the
end of a predefined length of cable.
Compensation will ensure the best measurement accuracy possible on a device at the
selected test conditions. When a measurement
is affected by a single residual component the
compensation is simple.
Take the case of stray lead capacitance
(C STRAY ) in parallel with the DUT capacitance
(C X), illustrated in Figure 12. The value of the
stray capacitance can be measured directly
with no device connected. When the device is
connected the actual DUT value can be determined by subtracting the stray capacitance
(C STRAY ) from the measured value (C MEASURE).
LCUR (-) LPOT
The only problem is, its not always this simple
when stray residuals are more than a single
component.
Kelvin
Test
Leads
Kelvin
Test
Leads
CSTRAY
CSTRAY
HPOT (+) HCUR
Test
Terminals
OPEN
Z
SHORT
CDUT
CDUT = CMEASURE -
CSTRAY
Figure 13: Open/Short
Figure 12: Lead Compensation
15
Load Correction
Load Correction is a compensation technique
which uses a load whose impedance is accurately known and applies a correction to measurements of similar components to substantially improve measurement accuracy. The purpose being to correct for non-linearity of the
measuring instrument and for test fixture or
lead effects which may be dependent on the
test frequency , test voltage, impedance range,
or other factors. Criteria for selecting the
appropriate load include:
a. Load whose impedance value is
accurately known.
b. Load whose impedance value is very
close to the DUT (this ensures that the
measuring instrument selects the same
measurement range for both devices).
c. Load whose impedance value is stable
under the measurement conditions.
d. Load whose physical properties allow it
to be connected using the same leads
or fixture as the DUT.
A prerequisite for load correction is to perform a
careful open/short compensation as previously
discussed. This feature, found on a number of
QuadTech LCR Meters, provides for an automatic load correction. The load's known value is
entered into memory, the load then measured,
and this difference then applied to ongoing
measurements.
Z actual = Z measure +/- delta Z
delta Z = the difference between the
known and the measured value of the
load.
Through the use of load correction it is possible
to effectively increase the accuracy of the
measuring instrument substantially, but this is
only as good as the known accuracy of the load
used in determining the correction.
16
Capacitance Measurements
Series or Parallel
Capacitors are one of the many components
used in electronic circuits. The basic construction of a capacitor is a dielectric material sandwiched between two electrodes. The different
types of capacitors are classified according to
their dielectric material. Figure 14 shows the
general range of capacitance values according
to their dielectric classification. Capacitance C,
dissipation factor D, and equivalent series
resistance ESR are the parameters usually
measured.
Capacitance is the measure of the quantity of
electrical charge that can be held (stored)
between the two electrodes. Dissipation factor,
also known as loss tangent, serves to indicate
capacitor quality. And finally, ESR is a single
resistive value of a capacitor representing all
real losses. ESR is typically much larger than
the series resistance of leads and contacts of
the component. It includes effects of the capacitor's dielectric loss. ESR is related to D by the
formula ESR =D/ωC where ω =2πf.
Advances in impedance measurement instrumentation and capacitor manufacturing techniques coupled with a variety of applications
has evolved capacitor test into what might be
considered a complex process. A typical equivalent circuit for a capacitor is shown in Figure
15. In this circuit, C is the main element of
capacitance. Rs and L represent parasitic components in the lead wires and electrodes and
Rp represents the leakage between the capacitor electrodes.
L
RS
C
RP
Figure 15: Capacitor Circuit
ALUMINUM ELECTROLYTIC
TANTALUM ELECTROLYTIC
METALIZED PLASTIC
CERAMIC
0.1
1.0
10
100
1000
0.01
0.1
1.0
picofarad (pF)
10
100
1000
microfarad (uF)
Figure 14: Capacitance Value by Dielectric Type
17
104
105
1F
When measuring a capacitor these parasitics
must be considered. Measuring a capacitor in
series or parallel mode can provide different
results, how they differ can depend on the quality of the device, but the thing to keep in mind is
that the capacitor's measured value most closely represents its effective value when the more
suitable equivalent circuit, series or parallel, is
used. To determine which mode is best, consider the impedance magnitudes of the capacitive reactance and Rs and Rp. For example,
suppose the capacitor modeled in Figure 16
has a small value.
Remember reactance is inversely proportional
to C, so a small capacitor yields large reactance
which implies that the effect of parallel resistance (Rp) has a more significant effect than
that of Rs. Since Rs has little significance in
this case the parallel circuit mode should be
used to more truly represent the effective value.
The opposite is true in Figure 17 when C has a
large value. In this case the Rs is more significant than Rp thus the series circuit mode
become appropriate. Mid range values of C
requires a more precise reactance-to-resistance comparison but the reasoning remains the
same.
The rule of thumb for selecting the circuit mode
should be based on the impedance of the
capacitor:
* Above approximately 10 kΩ use parallel mode
* Below approximately 10Ω use series mode
* Between these values follow manufacturers recommendation
If C = Low then Xc = High
and Rp becomes the most
significant resistance
CLOW
Rp
Rs
Figure 16: Rp more significant
If C = High then Xc = Low
and Rs becomes the most
significant resistance
CHIGH
Rp
Rs
Figure 17: Rs more significant
The menu selection, such as that on the
QuadTech 7000 Series LCR Meter, makes
mode selection of Cs, Cp or many other
parameters easy with results clearly shown on
the large LCD display.
Measuring Large and Small Values of
Capacitance
High values of capacitance represent relatively
low impedances, so contact resistance and
residual impedance in the test fixture and
cabling must be minimized. The simplest form
of connecting fixture and cabling is a two terminal configuration but as mentioned previously, it
can contain many error sources. Lead inductance, lead resistance and stray capacitance
between the leads can alter the result substantially. A three-terminal configuration, with coax
cable shields connected to a guard terminal,
Translated to a 1kHz test:
Use Cp mode below 0.01 µF and Cs mode
above 10 µF; and again between these values
either could apply and is best based on the
manufacturers recommendation.
18
can be used to reduce effects of stray capacitance. This is a help to small value capacitors
but not the large value capacitors because the
lead inductance and resistance still remains.
For the best of both worlds a four terminal configuration, discussed earlier and shown in
Figure 18, (often termed Kelvin) can be used to
reduce the effects of lead impedance for high
value capacitors. Two of the terminals serve for
current sourcing to the device under test, and
two more for voltage sensing. This technique
simply removes errors resulting from series
lead resistance and provides considerable
advantage in low impedance situations.
OPEN/SHORT compensation by the measuring
instrument. The open/short compensation
when properly performed is important in subtracting out effects of stray mutual inductance
between test connections and lead inductance.
The effect of lead inductance can clearly
increase the apparent value of the capacitance
being measured. Open/Short compensation is
one of the most important techniques of compensation used in impedance measurement
instruments. Through this process each residual parameter value can be measured and the
value of a component under test automatically
corrected.
One of the most important things to always
keep in mind is a concerted effort to achieve
consistency in techniques, instruments, and fixturing. This means using the manufacturers
recommended 4-terminal test leads (shielded
coax) for the closest possible connection to the
device under test. The open/short should be
performed with a true open or short at the test
terminals. For compensation to be effective the
open impedance should be 100 times the DUT
impedance and the short impedance 100 times
less than the DUT impedance. Of equal importance, when performing open/short zeroing, the
leads must be positioned exactly as the device
under test expects to see them.
IH
PH
+
D
U
T
V
-
PL
IL
A
Figure 18a: 4-Terminal to DUT
Besides a 4-terminal connection made as close
as possible to the device under test, a further
enhancement to measurement integrity is an
QuadTech
1730 LCR Digibridge
<MEAS DISPLAY>
1
0
FREQ. : 100 kHz
F1
Cs : 1.2345 pF
LEVEL : 1.00 V
F2
D : 1.2345
PARA : Cs - D
F3
NEXT PAGE 1/3
F4
LCUR
(-)
LPOT
HPOT
(+)
Figure 18b:
HCUR
l
4-Terminal to DUT
1730 LCR Meter
IH
and
Kelvin Clip Leads
PH
+
DUT
PL
-
IL
19
Equivalent Series Resistance (ESR)
If we define the dissipation factor D as the energy lost divided by the energy stored in a capacitor we can deduce equation 9.
Questions continually arise concerning the correct definition of the ESR (Equivalent Series
Resistance) of a capacitor and, more particularly, the difference between ESR and the actual
physical series resistance (which we'll call
Ras), the ohmic resistance of the leads and
plates or foils. Unfortunately, ESR has often
been misdefined and misapplied. The following
is an attempt to answer these questions and
clarify any confusion that might exist. Very
briefly, ESR is a measure of the total lossiness
of a capacitor. It is larger than Ras because the
actual series resistance is only one source of
the total loss (usually a small part).
At one frequency, a measurement of complex
impedance gives two numbers, the real part
and the imaginary part: Z = Rs + jXs. At that
frequency, the impedance behaves like a series
combination of an ideal resistance Rs and an
ideal reactance Xs (Figure 19). If Xs is negative, the impedance is capacitive and the reactance can be replaced with capacitance as
shown in equation 8.
8:
Xs =
9:
D=
=
Real part of Z
(-Imaginary part of Z)
Rs
(-) Xs
= RsωC
= (ESR) ωC
If one took a pure resistance and a pure capacitance and connected them in series, then one
could say that the ESR of the combination was
indeed equal to the actual series resistance.
However, if one put a pure resistance in parallel with a pure capacitance (Figure 20a) creating a lossy capacitor, the ESR of the combination is the Real part of Z = Real part of equation
10 as shown in Figure 20b.
10:
ωCs
1
1
Rp
=
+ jωCp
Rp
1 + ω2Cp2Rp2
From Figure 20a, however, it is obvious that
there is no actual series resistance in series
with the capacitor. Therefore Ras = 0, but
ESR > 0, therefore ESR > Ras.
We now have an equivalent circuit that is correct only at the measurement frequency. The
resistance of this equivalent circuit is the equivalent series resistance:
ESR = Rs = Real part of Z
Cp
RS
XS
energy stored
=
-1
DUT
energy lost
Rp
RP
RS
=
CS
= CP ( 1+
1
=
CS
a: parallel
b: series
Figure 20: ESR
Figure 19: Real Part of Z
20
+ ω2CP2RP2
1
ω2CP2RP2
)
Inductance Measurements
An inductor is a coiled conductor. It is a device
for storing energy in a magnetic field (which is
the opposite of a capacitor that is a device for
storing energy in an electric field). An inductor
consists of wire wound around a core material.
Air is the simplest core material for inductors
because it is constant, but for physical efficiency, magnetic materials such as iron and ferrites
are commonly used. The core material of the
inductor, its’ length and number of turns directly
affect the inductor’s ability to carry current.
In the case where the inductance is large, the
reactance at a given frequency is relatively
large so the parallel resistance becomes more
significant than any series resistance, hence
the parallel mode should be used. For very
large inductance a lower measurement frequency will yield better accuracy.
For low value inductors, the reactance
becomes relatively low, so the series resistance
is more significant, thus a series measurement
mode is the appropriate choice. For very small
inductance a higher measurement frequency
will yield better accuracy. For mid range values
of inductance a more detail comparison of reactance to resistance should be used to help
determine the mode.
The most important thing to remember whenever a measurement correlation problem occurs,
is to use the test conditions specified by the
component manufacturer. Independent of any
series/parallel decision, it is not uncommon for
different LCR meters to give different measured
results. One good reason for this is that inductor cores can be test signal dependent. If the
programmed output voltages are different the
measured inductance will likely be different.
Even if the programmed output voltage is the
same, two meters can still have a different
source impedance. A difference in source
impedance can result in a difference in current
to the device, and again, a different measured
value.
Coil of Wire, Air core = Inductor
Put
Current
Through
Wire
Produce
Magnetic Flux
Linkage
Out
Inductance =
Magnetic Flux
Current Through
Series or Parallel
As with capacitor measurements, inductor
measurements can be made in either a series
or parallel mode, use of the more suitable mode
results in a value that equals the actual inductance. In a typical equivalent circuit for an
inductor, the series resistance (Rs), represents
loss of the copper wire and parallel resistance
(Rp) represents core losses as shown in Figure
21.
LX
Inductance Measurement Factors
Here are four factors for consideration in
measuring actual inductors:
DC Bias Current
Constant Voltage (Voltage Leveling)
Constant Source Impedance
DC Resistance & Loss
There are other considerations such as core
material and number of coils (turns) but those
are component design factors not measurement factors.
RS
RP
Figure 21: Inductor Circuit
21
DC Bias Current
Since it is possible to apply large values of current and voltage to an inductor, CAUTION must
be taken when the current through an inductive
circuit is suddenly interrupted because a voltage transient then occurs across the open circuit. Put another way, if the current could be
instantly switched off, then the voltage would in
theory become infinite. This does not occur
because the high voltage develops an arc
across the switch as contact is broken, keeping
di/dt from becoming infinite. This does not however prevent the voltage from increasing to
potentially lethal levels. If a person breaks the
contact without the proper protection, the inductor induces a high voltage, forcing the current
through the person. Refer to Figure 22.
To get an accurate inductance measurement,
the inductor must be tested under actual (real
life) conditions for current flowing through the
coil. This cannot always be accomplished with
the typical AC source and a standard LCR
meter as the typical source in an LCR meter is
normally only capable of supplying small
amounts of current (<1mA). Inductors used in
power supplies need a larger current supply.
Instead of using a larger AC current source,
inductors are usually tested with a combination
of DC current and AC current. DC bias current
provides a way of biasing the inductor to normal
operating conditions where the inductance can
then be measured with a normal LCR meter.
The bottom line is that the measured inductance is dependent on the current flowing
through the inductor.
Constant Source Impedance
The current flowing through the inductor from
the AC source in the LCR meter must be held
constant. If the current is not held constant the
inductance measurements will change. This
change is generally a function of the LCR
meter's open circuit programmed test voltage.
The programmed voltage in an LCR meter is
obtained under an open circuit condition. A
source resistance (Rs, internal to the meter) is
effectively connected in series with the AC output and there is a voltage drop across this resistor. When a test device is connected, the voltage applied to the device depends on the value
of the source resistor (Rs) and the impedance
value of the device. The source impedance is
normally between 5Ω and 100kΩ.
Constant Voltage (Voltage leveling)
Since the voltage across the inductor changes
with impedance of the inductor and the impedance of the inductor changes with current, a
typical LCR meter designed for measurements
on capacitive and resistive devices can cause
the inductance to appear to drift. The actual
inductance is not drifting but is caused by the
voltage across the inductor not being constant
so the current is not constant. A voltage leveling circuit would monitor the voltage across the
inductor and continually adjust the programmed
source voltage in order to keep the voltage
across the inductor constant.
Figure 22: Breaking Contact Across an Inductor
22
DC Resistance and Loss
Eddy-Current Loss in iron and copper are due
to currents flowing within the copper or core
cased by induction. The result of eddy-currents
is a loss due to heating within the inductors copper or core. Eddy-current losses are directly
proportional to frequency. Refer to Figure 24.
Hysteretic Loss is proportional to the area
enclosed by the hysteresis loop and to the rate
at which this loop is transversed (frequency). It
is a function of signal level and increases with
frequency. Hysteretic loss is however independent of frequency. The dependence upon
signal level does mean that for accurate measurements it is important to measure at known
signal levels.
Measuring the DCR or winding resistance of a
coil of wire confirms that the correct gauge of
wire, tension and connection were used during
the manufacturing process. The amount of
opposition or reactance a wire has is directly
proportional to the frequency of the current variation. That is why DC resistance is measured
rather than ACR. At low frequencies, the DC
resistance of the winding is equivalent to the
copper loss of the wire. Knowing a value of the
wire's copper loss can provide a more accurate
evaluation of the total loss (DF) of the device
under test (DUT). (Refer to Figure 23).
Loss
Three possible sources of loss in an inductor
measurement are copper, eddy-current and
hysteretic. They are dependent on frequency,
signal level, core material and device heating.
As stated above, copper Loss at low frequencies is equivalent to the DC resistance of the
winding. Copper loss is inversely proportional
to frequency. Which means as frequency
increases, the copper loss decreases. Copper
loss is typically measured using an inductance
analyzer with DC resistance (DCR) measurement capability rather than an AC signal.
Inductance, L is blue
Direction
of
Magnetic
Flux
CURRENT
Eddy
Current
paths
Current
carrying
wire
Solid
Core
Figure 24: Eddy Currents induced in an iron core
Loss is red
1m
H
10m
H
100
mH
1H
10
100
1-
Resonance
Factor
1MHz
Frequency
Figure 23: Factors of Total Loss (Df)
23
f
fr
2
ωLo
+ GeωLo +
f
fr
2
Do
f
Die
lec
tric
Los
s, D
d~
1/f
0.001
1kHz
dy
Ed
De
s,
os
tL
n
rre
Cu
~f
Ro
1
D ~
2
0.01
~
Do
ss
Lo
ic
m
Oh
Dissipation Factor D = -1/Q
0.1
Do
Ohmic
Loss
De
Eddy
Current
Loss
Dd
Dielectric
Loss
Resistance Measurements
Series or Parallel
Of the three basic circuit components, resistors,
capacitors and inductors, resistors cause the
least measurement problems. This is true
because it is practical to measure resistors by
applying a dc signal or at relatively low ac frequencies. In contrast to this, capacitors and
inductors always experience ac signals that by
their very nature are prone to fluctuation, thus
these components are generally measured
under changing conditions. Resistors are usually measured at dc or low frequency ac where
Ohm's Law gives the true value under the
assumption that loss factors are accounted for.
The thing to keep in mind is that if resistors are
used in high frequency circuits they will have
both real and reactive components. This can
be modeled as shown in Figure 25, with a
series inductance (Ls) and parallel capacitance
(Cp).
LS
So how does one choose the series or parallel
measurement mode? For low values of resistors (below 1kΩ) the choice usually becomes a
low frequency measurement in a series equivalent mode. Series because the reactive component most likely to be present in a low value
resistor is series inductance, which has no
effect on the measurement of series R. To
achieve some degree of precision with low
resistance measurements it is essential to use
a four-terminal connection as discussed earlier.
This technique actually eliminates lead or contact resistance which otherwise could elevate
the measured value. Also, any factor that
affects the voltage drop sensed across a low
resistance device will influence the measurement. Typical factors include contact resistance and thermal voltages (those generated by
dissimilar metals). Contact resistance can be
reduced by contact cleanliness and contact
pressure.
RX
For high values of resistors (greater than several MΩ) the choice usually becomes a low frequency measurement in a parallel equivalent
mode. Parallel because the reactive component most likely to be present in a high value
resistor is shunt capacitance, which has no
effect on the measurement of parallel R.
CP
Figure 25: Resistor Circuit
For example, in the case of wire-wound resistors (which sounds like an inductor) its easy to
understand how windings result in this L term.
Even though windings can be alternately
reversed to minimize the inductance, the inductance usually increases with resistance value
(because of more turns). In the case of carbon
and film resistors conducting particles can
result in a distributed shunt capacitance, thus
the C term.
24
Precision Impedance Measurements
QuadTech manufactures several instruments
for the measurement and analysis of passive
component parameters. The 7000 Series LCR
Meter is an automatic instrument designed for
the precise measurement of resistance, capacitance and inductance parameters and associated loss factors. It is also suited for use in calibration and standards laboratories and can
assume many tasks previously performed only
by high priced, difficult to use, manually balanced impedance bridges and meters.
standard deviation to 5 ppm. It is therefore possible to measure the difference between two
impedances to approximately 10 ppm with the
7000. Averaging many measurements takes
time, however an automatic impedance meter
like the 7000 can take hundreds of averaged
measurements in the time it takes to balance a
high-resolution, manual bridge.
Measurement precision and confidence can be
further improved by using the 7000's median
measurement mode. In the median measurement mode, the instrument makes three measurements rather than one and discards the high
and low results. The remaining median measurement value is used for display or further processing (such as averaging). Using a combination of averaging and median measurements
not only increases basic measurement precision, but will also yield measurements that are
independent of a large errors caused by line
spikes or other non-Gaussian noise sources.
The ppm resolution of the 7000 is also not limited to values near full scale as is typically true
on six-digit, manual bridge readouts. In the
case of a manually balanced bridge, the resolution of a six-digit reading of 111111 is 9 ppm.
The 7000 does not discriminate against such
values; it has the same 0 .1 ppm resolution at
all values of all parameters including dissipation
factor (D) and quality factor (Q), the tangent of
phase angle.
Figure 26: 7400 Precision LCR Meter
Measurement Capability
The measurements of highest precision in a
standards lab are 1:1 comparisons of similar
impedance standards, particularly comparisons
between standards calibrated at the National
Institute of Standards and Technology (NIST)
and similar reference standards. This type of
measurement requires an instrument with high
measurement resolution and repeatability in
order to detect parts-per-million (ppm) differences rather than instruments with extreme,
direct-reading accuracy. In such applications,
two standards of very nearly equal value are
compared using "direct substitution"; they are
measured sequentially and only the difference
between them is determined.
The resolution of the 7000 is 0.1 ppm for the
direct measured values and such direct reading
measurements, at a one/second rate, have a
typical standard deviation of 10 ppm at 1 kHz.
By using the instrument's AVERAGING mode,
the standard deviation can be reduce by
1/(square root of N) where N is the number of
measurements averaged. Thus, an average of
5 measurements or more typically reduces the
Measured Parameters
Cs 17.52510 pF
DF 0.000500
Measuring
Freq
Range
Delay
1.0000kHz
AUTO
0ms
AC Signal
Average
Bias
1.000V
1
Off
Figure 27: Parts Per Million Resolution
25
The 7000 instrument also provides a unique
load correction feature that allows the user to
enter known values for both primary and secondary parameters, as illustrated in the load
correction display of Figure 28. The instrument
measures these values and automatically
applies the correction to ongoing measurements.
Basic Accuracy
Manufacturers of LCR meters specify basic
accuracy. This is the best-case accuracy that
can be expected. Basic accuracy does not take
into account error due to fixturing or cables.
The basic accuracy is specified at optimum test
signal, frequencies, highest accuracy setting or
slowest measurement speed and impedance of
the DUT. As a general rule this means 1VAC
RMS signal level, 1kHz frequency, high accuracy which equates to 1 measurement/second,
and a DUT impedance between 10Ω and
100kΩ. Typical LCR meters have a basic accuracy between ±0.01% and ±0.5%.
Load Correction
Measure
Primary Nominal
Secondary Nominal
Off
On
60.00000 pF
4.000000 m
Measuring Correction
Measured Primary
Measured Secondary
Freq
Range
60.25518 pF
.0042580
1.0000MHz
49
Primary
Secondary
Cs
Df
Actual Accuracy
If the measurements are to be made outside of
"optimum" conditions for basic accuracy, the
actual accuracy of the measurement needs to
be determined. This is done using a formula or
by looking at a graph of accuracy versus
impedance and frequency (refer to Figure 31).
It is also important to understand that the measurement range is really more a display range.
For example an LCR will specify a measurement range of 0.001nH to 99.999H this does
not mean you can accurately measure a
0.001nH inductor or a 99.9999H inductor, but
you can perform a measurement and the display resolution will go down to 0.001nH or up to
99.999H. This is really why it is important to
check the accuracy of the measurement you
want to perform. Do not assume that just
because the value you want to measure is within the measurement range you can accurately
measure it.
The accuracy formulas take into account each
of the conditions effecting accuracy. Most common are measurement range, accuracy/speed,
test frequency and voltage level. There are
addition errors including dissipation factor Df of
the DUT, internal source impedance and
ranges of the instrument, that effect accuracy.
HIT <START> TO MEASURE CORRECTION
HIT <ENTER> TO CHANGE VALUES
HIT <MENU> TO RETURN TO MAIN MENU
Figure 28: Entry of Values for Load Correction
Obviously, automatic instruments such as the
QuadTech 7000 have the significant advantage
of speed, since a balancing procedure is not
required. Balancing manual ac bridges is tiresome, time consuming and frequently requires
highly skilled personnel. Another advantage of
programmable instruments is the ability to create a fully automated system by utilizing the
instrument's RS-232 and IEEE-488.2 bus interface capability. With a computer based system,
correction calculations can be made without the
chance of human errors, especially the all too
common recording problems with + and - signs.
Instrument Accuracy
In determining how the instrument’s measurement capability is defined, take a look at the
specified accuracy of the instrument. Also, to
maintain the accuracy and repeatibility of measurements, the calibration procedure should be
investigated. A DUT’s measured value is only
as accurate as the instrument’s calibrated value
(plus fixture effects).
26
Factors Affecting Accuracy Calculations
Accuracy and Speed
Accuracy and speed are inversely proportional.
That is the more accurate a measurement the
more time it takes. LCR meters will generally
have 3 measurement speeds. Measurement
speed can also be referred to as measurement
time or integration time. Basic accuracy is
always specified with the slowest measurement
speed, generally 1 second for measurements
above 1kHz. At lower frequencies measurement times can take even longer because the
measurement speed refers to the integration or
averaging of at least one complete cycle of the
stimulus voltage. For example, if measurements are to be made at 10Hz, the time to complete one cycle is 1/frequency = 1/10Hz = 100
milliseconds. Therefore the minimum measurement speed would be 100ms.
Dissipation Factor (D) or Quality Factor (Q)
D and Q are reciprocals of one another. The
importance of D or Q is the fact that they represent the ratio of resistance to reactance or vice
versa. This means that the ratio Q represents
the tangent of the phase angle. As phase is
another measurement that an LCR meter must
make, this error needs to be considered. When
the resistance or reactance is much much
greater than the other, the phase angle will
approach ±90° or 0°. As shown in Figure 29,
even small changes in phase at -90° result in
large changes in the value of resistance, R.
DUT Impedance
High impedance measurements increase the
error because it is difficult to measure the current flowing through the DUT. For example if
the impedance is greater than 1MΩ and the test
voltage is one volt there will be less than 1mA
of current flowing through the DUT. The inability to accurately measure the current causes an
increase in error.
Low impedance measurements have an
increase in error because it is difficult to measure the voltage across the DUT. Most LCR
Meters have a resistance in series with the
source of 100k to 5 ohms. As the impedance of
the DUT approaches the internal source resistance the voltage across the DUT drops proportionally. If the impedance of the DUT is significantly less than the internal source resistance
then the voltage across the DUT becomes
extremely small and difficult to measure causing an increase in error.
Frequency
The impedance of reactive components is also
proportional to frequency and this must be
taken into account when it comes to accuracy.
For example, measurement of a 1µF capacitor
at 1 kHz would be within basic measurement
accuracy where the same measurement at
1MHz would have significantly more error. Part
of this is due to the decrease in the impedance
of a capacitor at high frequencies however
there generally is increased measurement error
at higher frequencies inherent in the internal
design of the LCR meter.
Resolution
Resolution must also be considered for low
value measurements. If trying to measure
0.0005 ohms and the resolution of the meter is
0.00001 ohms then the accuracy of the measurement cannot be any better than ±2% which
is the resolution of the meter.
Resistance
+jX
δ
-j(1/ωCs)
Reactance
XC
RS
+R
θ
Z
Impedance
-jX
Capacitive
Figure 29: Phase Diagram for Capacitance
27
Example: Accuracy Formula
The impedance range (Z RANGE ) is specified
in this table:
7600 Precision LCR Meter
Test Conditions:
1pF Capacitor at 1MHz
1VAC signal
Auto Range
Non-Constant Voltage
Slow Measurement Speed
Df of 0.001
ZRANGE =
In Voltage Mode
In Current Mode
100kΩ for Zm ³ 25k Ω
400Ω for I < 2.5mA
6kΩ for 1.6k Ω ≤ Zm < 25kW
25Ω for I > 2.5mA
6kΩ for Zm > 25k Ω and Fm > 25kHz
400Ω for 100 Ω ≤ Zm < 1.6k Ω
400Ω for Zm > 1.6kΩ and Fm > 250kHz
25Ω for Zm < 100Ω
The Calculated Accuracy using the formula in
Equation 11 is 3.7% substituting the values
listed herein.
Kt
=1
Zm
= 1/(2π*frequency*C)
Basic Accuracy of the 7600 is ±0.05%
Accuracy Formula for Slow Mode R, L, C, X,
G, B, |Z|, and |Y| is given in Equation 11.
Vs
= Test voltage in voltage mode,
Zm
= I * Zm in current mode*
= Impedance of DUT
Fm
= Test frequency
Kt
= 1 for 18 o to 28oC
ZRANGE
= 1/(2π*1000000*1x10-12)
= 159 kohms
= 400 ohms
Vfs
=1
Multiply A% = 8
A%
= 0.46%
= 2 for 8o to 38oC
Multiply A% times 8 due to Z m > 64 times
ZRANGE
= 4 for 5o to 45oC
VFS = 5.0 for 1.000V < Vs ≤ 5.000V
A% = 0.46% * 8 = 3.68%
1.0 for 0.100V < Vs ≤ 1.000V
0.1 for 0.020V ≤ Vs ≤ 0.100V
Refer to Equation 12 to fill in the numbers.
For Zm > 4* ZRANGE multiply A% by 2
For Zm > 16* ZRANGE multiply A% by 4
For Zm > 64* ZRANGE multiply A% by 8
*: For I * Zm > 3, accuracy is not specified
A% = + 0.025 + 0.025 +
.05
Zm
+ Zm x 10 -7
x
.2
VS
+ .8 x
Vfs
VS
+
(V S - 1) 2
4
Equation 11: 7600 Accuracy Formula
28
x
0.7 +
Fm
10 5
+
300
Fm
x Kt
Equation 12: Completed 7600 Accuracy Formula
A% = + 0.025 + 0.025 +
.05
159000
+
159000
x 10 -7
x
.2
1
Example 7600 Accuracy Graph
The accuracy could have been predicted without the use of a formula. If we calculate the
impedance of a 1pF capacitor at 1MHz we get
a value of:
+ .8 x
1
1
+
(1 - 1)2
4
1000000
x
0.7 +
+
300
10 5 1000000
x1
Use the graph in Figure 30 and substitute Z
for R. If we find the position on the graph for
an impedance value of 159kohms at 1MHz we
see a light blue or teal representing an accuracy of 3.45% to 3.65%. Overall the graph and
formula point to the same accuracy of ±3.5%.
Z = Xs = 1/(2π*frequency*capacitance)
Z = Xs = 1/(2π*1,000,000*0.000,000,000,001)
= 159kohms
3.6500%-3.8500%
Accuracy Z vs F Slow
3.4500%-3.6500%
3.2500%-3.4500%
0.1
3.0500%-3.2500%
2.8500%-3.0500%
1
2.6500%-2.8500%
10
1000
1.00E+04
1.00E+05
2.2500%-2.4500%
Impedance
100
2.4500%-2.6500%
2.0500%-2.2500%
1.8500%-2.0500%
1.6500%-1.8500%
1.4500%-1.6500%
1.2500%-1.4500%
1.0500%-1.2500%
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
50
0
10
%
1.00E+06
0.8500%-1.0500%
0.6500%-0.8500%
100
1000
1.00E+04
1.00E+05
5.00E+05
1.00E+07
1.00E+06 2.00E+06
0.4500%-0.6500%
0.2500%-0.4500%
Frequency
0.0500%-0.2500%
Figure 30: 7600 Accuracy Plot
29
Materials Measurements
where εo is the permittivity of a vacuum, and ε
the absolute permittivity.
Materials Measurement
Many materials have unique sets of electrical
characteristics which are dependent on its
dielectric properties. Precision measurements
of these properties can provide valuable information in the manufacture or use of these
materials. Herein is a discussion of dielectric
constant and loss measurement methods.
εo
=
0.08854pF/cm
The capacitance of a parallel-plate air capacitor (two plates) is:
C
=
Ka εo Area / spacing
where Ka is the dielectric constant of air:
Ka
= 1.00053
if the air is dry and at normal atmospheric
pressure.
Measurement Methods, Solids
Figure 31: QuadTech 7000 Meter with LD-3 Cell
Definitions
There are many different notations used for
dielectric properties. This discussion will use K,
the relative dielectric constant, and D, the dissipation factor (or tan δ) defined as follows:
ε'
K=
=
The Contacting Electrode Method
This method is quick and easy, but is the least
accurate. The results for K should be within
10% if the sample is reasonably flat. Refer to
Figure 32. The sample is first inserted in the cell
and the electrodes closed with the micrometer
until they just touch the sample. The electrodes
should not be forced against the sample. The
micrometer is turned with a light finger touch
and the electrometer setting recorded as hm.
εr
and
D = tan δ =
εr"
εr'
The complex relative permittivity is:
εr* =
ε
εo
= εr' - j (εr")
h=ho
ho
H
L
H
Figure 32:
L
Contact Electrode
G
G
Specimen
Cxm and Dxm
Air
Ca and Da
30
The LCR Meter should be set to measure parallel capacitance and the capacitance and dissipation factor of the sample measured as Cxm
and Dxm.
The Air-Gap Method
This method avoids the error due to the air
layer but requires that the thickness of the
sample is known. Its thickness should be
measured at several points over its area and
the measured values should be averaged to
get the thickness h. The micrometer used
should have the same units as those of the
micrometer on the cell.
The electrodes are set to about .02 cm or .01
inch greater than the sample thickness, h, and
the equivalent series capacitance and D measured as Ca and Da. Note the micrometer setting as hm which can be corrected with the
micrometer zero calibration, hmo to get:
The electrodes are opened and the sample
removed and then the electrodes closed to the
same micrometer reading, hm. C (parallel) and
D of empty cell are measured as Ca and Da.
Calculate Kx and D x of the sample from:
Kx = (1.0005)
C xm
Ca
and
Dx = (D xm - D a)
ho = (hm + h mo)
The factor 1.0005 in the formula for Kx corrects
for the dielectric constant of (dry) air.
Subtracting D a from Dxm removes any constant
phase error in the instrument. For even better D
accuracy, the electrode spacing can be adjusted until the measured capacitance is approximately equal to Cxm, and then Da measured.
The sample is inserted and measured as Cxa
and Dxa . Calculate:
(ho - h)
M =
ho
Ca
Ca - MC xa
D = (Dxa - D a)
Note that both Kx and Dx will probably be too
low because there is always some air between
the electrodes and the sample. This error is
smallest for very flat samples, for thicker samples and for those with low K and D values.
(1-M) Cxa
Ca - MC xa
Kx =
ho
1.0005
1 + D x2
h
H
H
Figure 33:
Air Gap Method
L
L
G
G
Air
Ca and Da
31
Specimen and Air
Cxa and Dxa
Dow Corning 200, 1 centistoke viscosity, is
most generally satisfactory.
The four measurements of series capacitance
and D are outlined in the Figure 34. Note the
spacing is the same for all measurements and
should be just slightly more than the specimen
thickness. The accuracy will be limited mainly
by the accuracy of the measurements made.
From these measurements calculate:
The factor (1 + D x2 ) converts the series value of
Cx to the equivalent parallel value and is not
necessary if Dx is small. The factor of 1.0005
corrects for the dielectric constant of air (if dry).
The formula for Dx assumes that the true D of
air is zero and it makes a correction for a constant D error in the instrument.
The Two-Fluid Method
This method is preferred for specimens whose
thickness is difficult to measure and for best
accuracy which will be limited by the accuracy
of the C and D measurements. However it
requires four measurements, two using a second fluid (the first being air). The dielectric
properties of this fluid need not be known, but it
must not react with the specimen and it must be
stable and safe to use. A silicone fluid such as
h
ho
C xser
Ca
= 1-
=
CaC f (C xf - C xa)
Cxa Cxf (C f - C a)
C xf C xa (C f - C a)
Ca
(C xaCf - C xf C a)
which is the ratio of the equivalent series
capacitance of the sample to Ca .
ho
h
H
L
H
L
G
G
Air
Ca and Da
Specimen and Air
Cxa and Dxa
Figure 34: Two
Fluid Method
ho
h
H
L
H
L
G
G
Fluid
Cf and Df
Specimen and Fluid
Cxf and Dxf
32
If Dx is close to Df or larger use:
Dx = D xf +
C a (C xf - C xa) (D xf - D f)
(C xaCf - C xf C a)
If Dx is very small use:
Dx =
(Dxa - D a) C xf (C f - C a)
(C xaCf - C xf C a)
which makes a zero D correction.
From the above results calculate:
Kx =
h
C xser
1.0005
ho
Ca
1 + D x2
As before, the factor of 1.0005 corrects for the
dielectric constant of air (if dry) and the factor
(1 + Dx 2) converts Cx to equivalent parallel
capacitance.
Measurement Methods, Liquids
Measurements on liquids are simple, the only
difficulty is with handling and cleanup.
Equivalent parallel capacitance and D of air (Ca
and Da), is measured first and then that of the
liquid (Cxm and Dxm)
Determine Kx and Dx :
Kx =
Cxm
Ca
1.0005
Dx = (D xm - D a)
Note that the spacing is not critical but should
be narrow enough to make the capacitance
large enough to be measured accurately.
33
Recommended LCR Meter Features
As with most test instrumentation, LCR meters
can come with a host of bells and whistles but
the features one most often uses are
described herein.
tance (B), phase angle (θ) and ESR can more
fully define an electrical component or material.
Test Frequency
In order to measure both low and high impedance values measuring instrument must have
several measurement ranges. Ranging is usually done automatically and selected depending
on the impedance of the test device. Range
changes are accomplished by switching range
resistors and the gain of detector circuits. This
helps maintain the maximum signal level and
highest signal-to-noise ratio for best measurement accuracy. The idea is to keep the measured impedance close to full scale for any given
range, again, for best accuracy.
Ranging
Electrical components need to be tested at the
frequency in which the final product/application
will be utilized. An instrument with a wide frequency range and multiple programmable frequencies provides this platform.
Test Voltage
The ac output voltage of most LCR meters can
be programmed to select the signal level
applied to the DUT. Generally, the programmed
level is obtained under an open circuit condition. A source resistance (Rs, internal to the
meter) is effectively connected in series with
the ac output and there is a voltage drop across
this resistor. When a test device is connected,
the voltage applied to the device depends on
the value of the source resistor (Rs) and the
impedance value of the device.
Averaging
The length of time that an LCR meter spends
integrating analog voltages during the process
of data acquisition can have an important effect
on the measurement results. If integration
occurs over more cycles of the test signal the
measurement time will be longer, but the accuracy will be enhanced. This measurement time
is usually operator controlled by selecting a
FAST or SLOW mode, SLOW resulting in
improved accuracy. To enhance accuracy, the
measurement averaging function may be used.
In an averaging mode many measurements are
made and the average of these is calculated for
the end result.
Accuracy/Speed
Classic trade-off. The more accurate your
measurement the more time it takes and conversely, the faster your measurement speed the
less accurate your measurement. That is why
most LCR meters have three measurement
speeds: slow, medium and fast. Depending on
the device under test, the choice is yours to
select accuracy or speed.
Median Mode
A further enhancement to accuracy can be
obtained by employing the median mode function. In a median mode 3 measurements might
be made and two thrown away (the lowest and
the highest value). The median value then represents the measured value for that particular
test.
Measurement Parameters
Primary parameters L, C and R are not the only
electrical criteria in characterizing a passive
component and there is more information in the
Secondary parameters than simply D and Q.
Measurements of conductance (G), suscep34
Computer Interface
Display
Many testers today must be equipped with
some type of standard data communication
interface for connection to remote data processing, computer or remote control. For an
operation retrieving only pass/fail results the
Programmable Logic Control (PLC) is often
adequate, but for data logging it's a different
story. The typical interface for this is the IEEE488 general purpose interface bus or the RS232 serial communication line.
These interfaces are commonly used for monitoring trends and process control in a component manufacturing area or in an environment
where archiving data for future reference is
required. For example when testing 10% components, the yield is fine when components test
at 8% or 9%, but it does not take much of a shift
for the yield to plummet. The whole idea of production monitoring is to reduce yield risks and
be able to correct the process quickly if needed.
An LCR Meter with remote interface capability
has become standard in many test applications
where data logging or remote control have
become commonplace.
An instrument with multiple displays provides
measured results by application at the press of
a button. Production environments may prefer
a Pass/Fail or Bin Summary display. R&D Labs
may need a deviation from nominal display.
The 7000 series instruments have seven display modes: measured parameters, deviation
from nominal, % deviation from nominal,
Pass/Fail, Bin Summary, Bin Number and No
Display. Refer to Figure 35. Figure 36 illustrates three of the 7000 Series display modes.
QuadTech
7400
DISPLAY
Setup
I/O
Display
Analysis
Utilities
Measured Parameters
Deviation from Nominal
% Deviation from Nominal
Pass / Fail
Bin Summary
Bin Number
No Display
HIT MENU TO RETURN TO MAIN MENU
Figure 35: 7600 Display Menu
SELECT
ENTRY
TEST
PRECISION
LCR METER
!
CAUTION
HIGH VOLTAGE
255.2
1
2
3
MENU
4
5
6
CNCL
STOP
7
8
9
ENTER
START
-
0
.
204.3
153.4
102.5
IL
IH
51.59
IZI Ω
10.00
572.9
32.82k
2.000M
FREQUENCY Hz
PL
PH
0
Measured Parameters
Pass / Fail
Ls 158.450uH
Q 1.000249
Cs 17.52510 pF
DF 0.000500
PASS
Measuring
Freq
Range
Delay
AC Signal
Average
Bias
Measured Parameters
Freq
Range
Delay
AC Signal
Average
Bias
Bin
Low LIMIT
1
2
3
4
5
11
12
13
14
15
Totals:
90.00 k
100.00 k
110.00 k
120.00 k
130.00 k
PRI Pass SEC Fail
LOWPass SEC Fail
PRI
HI
PRI Fail SEC Pass
PRI Fail SEC Fail
NO CONTACT
Pass 595
High LIMIT
110.00
120.00
130.00
140.00
150.00
Figure 36: Example 7600 Display Modes
k
k
k
k
k
Fail 190
HIT <MENU> TO RETURN TO MAIN MENU
Pass / Fail
35
1
Bin Totals
Total
250
100
90
80
75
60
55
50
20
5
785
Bin 3
Bin 2
Bin 1
Measured
Value
N
-1%
+1%
-5%
+5%
-7%
Figure 37:
+10%
Nominal Value
100.00kΩ
Nested Limits
Binning
Sequential Limits
Sequential limits are a natural choice when
sorting components by absolute value. Figure
38 illustrates the use of sequential limits for a
total of three bins. Sequential bins do not have
to be adjacent. Their limits can overlap or have
gaps depending upon the specified limit. Any
component that falls into an overlap between
bins would be assigned to the lower numbered
bin and any component that falls into a gap
between bins would be assigned to the overall
fail bin.
A necessary production application, binning
sorts components by test results quickly by a
predetermined value set by the test engineer.
Two of the most common methods of sorting
results into bins are using nested limits or
sequential limits.
Nested Limits
Nested limits are a natural choice for sorting
components by % tolerance around a single
nominal value with the lower bins narrower than
the higher numbered bins. Nested limits for
three bins are illustrated in Figure 37. Note that
the limits do not have to by symmetrical (Bin 3
is -7% and +10%).
Bin 1
Bin 2
Bin 3
Measured
Value
85kΩ
90kΩ
100kΩ
120kΩ
Figure 38:
Sequntial Limits
36
Test Sequencing
Figure 39 illustrates the parameter sweep function of the 7000 Series instrument.
A sequence of tests, each with different test
parameters and conditions can be performed
on a single component. Combined with the binning process, test sequencing enables multiple
tests on a single component and then sorting by
test. This is a great electrical characterization
tool for finding out under which conditions your
particular component fails.
Bias Voltage and Bias Current
A bias voltage or bias current function enables
real time operating conditions to be applied to
the device under test. Bias an inductor with
DC current of 1-2mA to simulate the current
running through it in its real application (such
as in a power supply).
Parameter Sweep
Another excellent device characterization tool
of LCR meters is the parameter sweep function.
A sweep is a user-defined number of measurements for a particular test. The QuadTech 7000
Series instruments display a table or plot of
measured results versus a test variable such as
frequency, voltage or current. The user defines
the lower boundary of the sweep in Hz, Volts or
Amps; the upper boundary in Hz, Volts or Amps;
the step or number of increments in the sweep
and the format (table or plot).
Setup
I/O
Constant Source Impedance
An LCR meter with a constant source impedance, will provide a source resistance (Rs) that
will hold the current constant. Therefore one
knows what the voltage at the DUT will be. Rs
is in series with the ac output such that the programmed voltage is 1V but the voltage to the
test device is 0.5V. Refer to Figure 40.
Analysis
Sweep
Parameter
Freq
Voltage
Sweep Begin = 10.0 Hz
Sweep End = 1.0000 kHz
Sweep Step
25
Sweep Format Table
50
Plot
Figure 39:
Utilities
Parameter Sweep Function
Current
100
200
HIT MENU TO RETURN TO MAIN MENU
Sweep Parameter Setup
Plot Table
Frequency
DF
Cs
1.0000kHz
471.4576nF
0.003135
1.2915kHz
470.4563nF
0.003675
1.6681kHz
469.8878nF
0.003867
2.1544kHz
468.9983nF
0.010035
2.7825kHz
466.4532nF
0.010078
3.5938kHz
462.6634nF
0.011045
4.6415kHz
460.6645nF
0.012895
5.9948kHz
459.7892nF
0.014786
7.7426kHz
458.7845nF
0.016782
10.000kHz
456.5454nF
0.018544
200.0
180.0
160.0
140.0
120.0
Prev
Page
100.0
IZI Ω
Next
Page
50.000k
51.000k
54.000k
Frequency Hz
Sweep Table
Sweep Plot
37
62.000k
1910 Source Resistance
RS =25Ω
V PROGRAM
VP = 1V
VM= VP
Z X= R+jX
R = 25Ω
X = 0Ω
VM= ?
R2+ X2
(RS + R)2 + X2
DUT
V MEASURE
I MEASURE
Figure 40: Constant Source Impedance
Monitoring DUT Voltage & Current
Monitoring the voltage across or current
through the DUT during test enables real time
analysis of the device. If the voltage can be
kept level (constant) across a DUT then the
impedance can be measured accurately. In
inductor measurements it is necessary to keep
the voltage across the inductor constant
because the voltage across an inductor
changes with the impedance of the inductor
which changes with the current through it. So
the ability to monitor the voltage and current to
the DUT will provide the most accurate conditions for impedance measurement.
Figure 41: Digibridge Family: 1689 & 1689M
38
Examples of High Performance Testers
Examples of passive component measuring
instrumentation manufactured by QuadTech,
Inc of Maynard Massachusetts is provided
herein. Included are: Digibridges, Precision
LCR Meters and Impedance Analyzers.
1692 LCR Digibridge
Digibridges
The 1600 and 1700 Series digital bridges are
high performance passive component testers.
Figure 42: 1692 Digibridge
1600 Series
•
Measurement Parameters: R/Q, L/Q, C/R, C/D
Common Features
•
Test Frequency: 100Hz, 120Hz, 1kHz, 10kHz
and 100kHz
•
Full five digit display for primary L,C & R
•
Four digit display for secondary D, Q
•
Accuracy: 0.05% LCR; 0.0003 DQ
•
Continuous or Triggered Measurement Mode
•
Applied Voltage: 0.3V to 1.0V maximum
•
Open & Short Circuit Compensation
•
2, 4 or 8 measurements/second
•
DC Bias: Internal to 2V, External to 60V
•
Constant Voltage Mode (25Ω Source)
•
Auto Ranging with Manual Hold
•
Single Triggered Measurement or 1-10 Averaged
•
Pass/Fail Bins for Component Sorting
•
Charged Capacitor Protection
•
Optional IEEE 488 and Handler Interfaces
•
Full Range of Accessory Options
1693 LCR Digibridge
1659 LCR Digibridge
•
Measurement Parameters: R/Q, L/Q, C/R, C/D
•
Test Frequency: 100Hz, 120Hz, 1kHz, 10kHz
•
Accuracy: 0.1% LCR; 0.0005 DQ
•
Applied Voltage: 0.3V maximum
•
2, 4 or 8 Measurements per second
Figure 43: 1693 Digibridge
1689/89M LCR Digibridge
•
Measurement Parameters: R/Q, L/Q, C/R, C/D,
R/X, G/B, Z/θ, Y/θ
•
500 Test Frequencies: 12Hz to 200kHz
•
Accuracy: Primary 0.02% L,C,R, G, Z, Y
Secondary: 0.0002 DQ; 0.01 o θ
•
Measurement Parameters: R/Q, L/Q, C/R, C/D
•
Programmable Test Voltage: 5mV to 1.275V
•
Programmable Test Frequency: 12Hz to 100kHz
•
Up to 50 measurements/second*
•
Accuracy: 0.02% LCR; 0.0001 DQ
•
Constant Voltage Mode (25Ω Source)
•
Programmable Test Voltage: 5mV to 1.275V
•
Median Value Mode
•
1689: Up to 30 measurements/second*
•
1689M: Up to 50 measurements/second*
•
Constant Voltage Mode (25Ω Source)
•
Median Value Mode
* With High Speed Option
* With High Speed Option
39
1700 Series
Common Features
•
Guarded 4-Terminal Kelvin Connection
•
Selectable Test Voltage & Frequency
•
Selectable Measurement Rate
•
External DC Bias Voltage
•
Full Range of Accessory Options
Figure 45: 1730 Digibridge
1730 LCR Digibridge
1715 LCR Digibridge
Figure 44: 1715 Digibridge
•
12 Measurement Parameters
•
Accuracy: 0.1% LCR; 0.0001 DQ
•
7 Test Frequencies: 100Hz to 100kHz
•
Programmable Test Voltage: 10mV to 1.0V
•
Up to 62 measurements/second
•
Programmable Source Impedance
•
IEEE-488 & Handler Interfaces, Standard
•
Monitor DUT Voltage & Current
•
11 Measurement Parameters
•
Storage/Recall of 50 Setups
•
Test Frequency: 100Hz, 120Hz, 1kHz & 10kHz
•
Pass/Fail Binning
•
Basic Accuracy: 0.2% LCR; 0.002 DQ
•
Measurement Averaging (1-256)
•
Test Signal: 0.25V or 1.0V
•
Measurement Delay (0-10 seconds)
•
Up to 25 measurements/second
•
DC Bias Voltage: 0-5V
•
Programmable Source Impedance
•
Automatic Open/Short Zeroing
•
Open/Short Compensation
•
Comparator: Primary/Secondary Hi/Lo Limits
•
Binning: 8 Bins Primary/Secondary
•
RS-232 Interface, Standard
•
IEEE-488 & Handler Interfaces, Optional
40
Precision LCR Meters
1920 Precision LCR Meter
The 1900 and 7000 Series digital LCR meters
are precise impedance analyzers with a host of
useful functions for component testing and data
analysis.
1900 Series
Common Features
•
20 Measurement Parameters
•
Basic Accuracy: 0.1% LCR; 0.001 DQ
•
27,000 Test Frequencies: 20Hz to 1MHz
•
Programmable Test Voltage: 20mV to 1.0V
•
Up to 40 measurements/second
•
DC Bias Voltage: 0V to 2.0V, Internal
•
DC Resistance Measurements: 0.1mΩ-100kΩ
•
Monitor DUT Voltage & Current
•
Storage/Recall of 30 Single tests, 10 Sequential
•
14 Pass/Fail Bins
•
Measurement Averaging (1-1000)
•
Measurement Delay (0 to 1000 ms)
•
Open/Short Zeroing
•
Displays Usage & Calibration Data
•
High Performance, Fast, Production Oriented
•
Wide Frequency Range
•
Automatic Test Sequencing
•
Internal, External or Manual Trigger
•
Programmable Source Impedance
•
Constant Voltage Mode (Voltage Leveling)
•
IEEE-488, RS232 & Handler Interfaces, Std.
•
Built-In Automatic Calibration Procedure
•
Cable Compensation (1M, 2M, no cable)
7000 Series
•
Self Test Routine- Verify Instrument Operation
Common Features
Figure 46: 1910 Inductance Analyzer
1910 Inductance Analyzer
•
20 Measurement Parameters
•
Basic Accuracy: 0.1% LCR; 0.001 DQ
•
27,000 Test Frequencies: 20Hz to 1MHz
•
Programmable Test Voltage: 20mV to 1.0V
•
Up to 40 measurements/second
•
DC Bias Current: 1mA to 1A
•
DC Resistance Measurements: 0.1mΩ-100kΩ
•
Monitor DUT Voltage & Current
•
Storage/Recall of 30 Single tests, 10 Sequential
•
14 Pass/Fail Bins
•
Measurement Averaging (1-1000)
•
Measurement Delay (0 to 1000 ms)
•
Open/Short Zeroing
•
Displays Usage & Calibration Data
•
Fast, Precise, Production and R&D Oriented
•
Wide Frequency Range
•
Programmable Test Voltage & Current
•
Graphical and Tabular Display
•
Automatic Test Sequencing
•
Swept Frequency & Signal Level Measurements
•
Internal, External or Manual Trigger
•
AutoAcc (Automatic Accuracy Calculation)
•
Built-In Calibration Routine
•
IEEE-488, RS232, Handler, Parallel Printer and
3.5” Disk Drive Interfaces, Standard
•
Internal Storage of Test Setups & Floppy Drive
•
Full Range of Accessory Options
Figure 47: 7400 Precision LCR Meter
41
Dedicated Function Test Instruments
7400 Precision LCR Meter
•
14 Measurement Parameters
•
Basic Accuracy: 0.05% LCR; 0.0005 DQ
•
Programmable Test Frequency: 10Hz to 500kHz
•
Programmable Test Voltage: 20mV to 5.0V
•
Programmable Test Voltage: 250uA to 100mA
•
Up to 40 measurements/second
•
DC Bias Voltage: 0V to 2.0V, Internal
•
DC Bias Voltage: 0V to 200V, External
•
DC Bias Voltage: 0V to 500V, External (7400A)
•
Internal Storage/Recall of 25 Setups
•
15 Pass/Fail Bins
•
Measurement Averaging (1-1000)
•
Measurement Delay (0 to 1000 ms)
•
Charged Capacitor Protection
•
Displays Usage & Calibration Data
In addition to passive compent test instrumentation, QuadTech manufactures milliohmmeters, megohmeters, AC/DC Hipot Testers and
Electrical Safety Analyzers. View Product specifications at http://www.quadtech.com.
Milliohmmeters
Figure 49: LR2000 Milliohmmeter
Megohmmeters
7600 Precision LCR Meter
•
14 Measurement Parameters
•
Basic Accuracy: 0.05% LCR; 0.0005 DQ
•
Programmable Test Frequency: 10Hz to 2MHz
•
Programmable Test Voltage: 20mV to 1.0V
•
Programmable Test Voltage: 250uA to 100mA
•
Up to 25 measurements/second
•
DC Bias Voltage: 0V to 2.0V, Internal
•
DC Bias Voltage: 0V to 200V, External
•
DC Bias Voltage: 0V to 500V, External (7600A)
•
Internal Storage/Recall of 25 Setups
•
15 Pass/Fail Bins
•
Measurement Averaging (1-1000)
•
Measurement Delay (0 to 1000 ms)
•
Charged Capacitor Protection
•
Displays Usage & Calibration Data
Figure 50: 1865 Megohmmeter
Hipot Testers
Figure 51: Sentry Plus Series Hipot Tester
Electrical Safety Analyzers
Figure 52: Guardian 6000 Series
Figure 48: 7600 Precision LCR Meter
Production Safety Analyzer
42
Appendix A
43
Nationally Recognized Testing Laboratories (NRTL’s) and
Standards Organizations*
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Underwriters Laboratories, Inc.
333 Pfingsten Road Northbrook, Illinois 60062 USA
Tel: 847-272-8800, http://www.ul.com
American National Standards Institute
1 West 42nd Street New York, NY 10036
Tel: 212-642-4900, FAX: 212-398-0023 http://www.ansi.org
British Standards Institution
389 Chiswick High Road London W4 4AL United Kingdom
http://www.bsi.org.uk
CENELEC Comité Européen de Normalisation Electrotechnique
Rue de Stassart, 35 B - 1050 BRUSSELS
Tel: + 32 2 519 68 71, FAX: + 32 2 519 69 19, http://www.cenelec.be
Canadian Standards Association
Central Office 178 Rexdale Boulevard Etobicoke (Toronto), Ontario M9W 1R3
Tel: 416-747-4000 or 1-800-463-6727, http://www.csa.ca
VDE-Verband Deutscher Elektrotechniker
Merlinstrasse 28 D-63069 Offenbach Federal
Republic of Germany
http://www.vde.de
Japanese Standards Association
1-24, Akasaka 4, Minato-ku Tokyo 107 Japan
IEC International Electrotechnical Commission
3, rue de Varembé o PO Box 131 1211 Geneva 20 o Switzerland
Tel: +41 22 919 02 11 FAX: +41 22 919 03 00, http://www.iec.ch
The Institute of Electrical and Electronic Engineers, Inc
345 East 47th Street New York, New York 10017
Tel: 800-678-IEEE http://www.ieee.org
NIST National Institute of Standards and Technology Calibration Program
Bldg. 820, Room 232, Gaithersburg, MD 20899
Tel: 301-75-2002, FAX: 301-869-3548, http://www.nist.gov
National Electric Manufacturers Association Standards Publication Office
2101 L. Street, N.W. Suite 300 Washington, D.C. 20037 USA
Tel: 202-457-8400 FAX: 202-457-8473, http://www.nema.org
ISO International Standards Organization
1, rue de Varembé Case postale 56 CH-1211 Genève 20 Switzerland
Tel: + 41 22 749 01 11, FAX: + 41 22 733 34 30, http://www.iso.ch
OSHA Region 1 Regional Office
JFK Federal Building, Room E340 Boston, Massachusetts 02203
Tel: 617-565-9860, FAX: 617-565-9827, http://www.osha.gov
TÜV Rheinland of North America, Inc.
12 Commerce Road Newton, CT 06470
Tel: 203-426-0888 http://www.us.tuv.com
* Partial Listing
44
Helpful Links
TYPE
Parts
874 Connectors
NAME
ADDRESS
TELEPHONE
WEBSITE
Gilbert Engineering
800-528-5567
http://www.gilbertconnectors.com
874 Connectors
Microwave Distributors
800-637-4353
http://microwavedistributors.com
900 Connectors
Maury Microwave
5310 West Camelback Rd
Glendale AZ 85301
1707-32 Vet. Mem. HW
Islandia NY 11722
2900 Inland Empire Blvd.
Ontario CA 91764
909-987-4715
http://maurymw.com
Equipment
ATE for Circuit boards
Teradyne Inc
321 Harrison Avenue
Boston, MA 02118-2238
P.O. Box 222
14 Commerce Drive
Danbury CT 06813
178 Orchard Street
Watertown, MA 02172
RD#1 Box 117
Yukon PA 15698
617-482-2700
http://www.teradyne.com
724-722-3400
http://www.verteximage.com
IET Labs
10 Dedham Street
Newton MA 02461
534 Main Street
Westbury, NY 11590
800-475-1211
http://www.ietlabs.com
Canon
Communications
Conformity Magazine
310-445-4200
http://www.ce-mag.com
978-486-0888
http://www.conformity.com
617-558-4671
http://www.e-insite.net/ednmag
516-227-1300
http://www.electronicproducts.com
516-562-5325
(Fax)
941-966-9521
http://www.eetimes.com
919-468-0384
http://www.paumanokgroup.com/
617-558-4671
http://www.e-insite.net/tmworld
Variacs
Power Designs
Jerry Voity
Dielectric Cells
Dielectric Products Co.
Gerard Gilkie
Vertex Image Products
Chuck Bobich
Dielectric Cells
Standards
Inductance,
Capacitance &
Resistance Standards;
Decades, Strobes
Magazines
Compliance
800-682-8235
617-924-5688
EE Times
Reed Business Info.
(Formerly Cahners)
Hearst Business
Publishers
CMP Media Inc
Evaluation Engineering
Nelson Publishing
Passive Component
The Paumanok Group
Test & Measurement
World
Resources
The Capacitor Source
Product Sites
Electronics
Reed Business Info.
(Formerly Cahners)
11444 W. Olympic Bd.
Los Angeles, CA 90064
531 King Street
Littleton, MA 01460
275 Washington Street
Newton, MA 02458
645 Stewart Avenue
Garden City, NY 11530
600 Community Drive
Manhasset, NY 11030
2500 Tamiami Trail North
Nokomis, FL 34275
132 Preston Exec. Dr.
Cary NC 27513
275 Washington Street
Newton MA 02458-1630
FaradNet
Knoxville, TN 37922
865-966-8958
http://www.faradnet.com
GlobalSpec Inc
350 Jordan Road
Troy, NY 12180
518-880-0200
http://www.globalspec.com
Electronics
ChipCenter
Conformity
EDN
Electronic Design News
Electronic Products
http://evaluationengineering.com
http://www.chipcenter.com
45
Typical Measurement Parameters
for a
Variety of Components and Materials**
Component
Capacitors
Frequency
60 Hz
Voltage
.1,.3,1
Equiv. Circuit
Series
Quantity
C, D
120 Hz
Low, DC bias
Series
C, D
Series
ESR, |Z|
"
Inductors
Type
Electrolytic,
Non-polarized
Electrolytic,
Polarized
Electrolytic,
Polarized
Plastic, Ceramic
> 1000pF
Ceramic < 1000pF
High-valued
"
Resistors
"
"
"
"
100K-1MHz
1kHz
.1 – 1V AC
Series
C, D
1MHz
50 - 1000 Hz
.1 – 1V AC
varies
Series/parallel
Parallel
Low-valued (rf)
Low values
High values
1k - 1MHz
DC - 1kHz
DC - 100Hz
low
varies
varies
Series
Series
Parallel
Materials
Insulators
DC, 1k, 1M
1, HV DC
Parallel
"
"
"
Motors &
Transformers
"
"
Cables
"
"
Battery
Circuit board
Network
Semiconductors
Conductors
Magnetic
Capacitance
dc, low freq.
100, 1k
50-1 kHz
1k, 1M
varies
any
varies
1
Parallel
Series
Series/parallel
Parallel
C, D
L, Q, RP
L, Q, Rs
R, Q, L
R, Q, CP
C, D, R, G,
dielectric const, K
C, G, C vs. V
R, Q, L
L, Q, R
C, D
Inductance
Resistance
Capacitance
Inductance
Impedance
Impedance
Impedance
Impedance
50Hz to 1MHz
DC, 100Hz
1k, 1M
as required
1k, 1M
100,1k
1k, 1M
as required
1
1
1
any
any
1
1
any
Series
Series
Series
Series
Series/parallel
Series
Series
Series/parallel
Filters
Impedance
as required
any
Series/parallel
as required
as required
any
any
Series/ parallel
Series/ parallel
Transducers
Sensors
L, Q
R, Q
C
L
Z
Z, R
C, Z, L, G
R. L, C, Q, G, Z,
G, Y, θ
R, L, C, Q, G, Z,
G, Y, θ
Z, C, L, R, θ
all
** Partial Listing, Check Standard and Governing/Certifying Agency for specific requirements.
46
Impedance Terms and Equations*
Parameter
Z
Quantity
Impedance
Unit Symbol
ohm, Ω
|Z|
Magnitude of Z
ohm, Ω
Rs or ESR
Resistance,
Real part of Z
ohm, Ω
Xs
Reactance,
Imaginary part of Z
ohm, Ω
Y
Admittance
siemen, S
|Y|
Magnitude of Y
siemen, S
(was mho)
GP
Real part of Y
siemen, S
BP
Susceptance
siemen, S
Formula
1
=| Z | ε
Y
1
| Z |= R S 2 + X S 2 =
|Y |
G
RP
RS = 2 P 2 =
1 + Q2
GP + B P
Z = R S + jX S =
XS =−
jθ
BP
G P + BP
1
Y = GP + jB P = =| Y | ε jφ
Z
1
| Y |= G P 2 + B P 2 =
|Z|
R
GP = 2 S 2
RS + X S
BP = −
Cs
Series capacitance
farad, F
CP
Parallel capacitance
farad, F
Ls
Series inductance
henry, H
LP
Parallel inductance
henry, H
RP
Parallel resistance
ohm, Ω
Q
Quality factor
none
D, DF or
tan δ
Dissipation factor
none
θ
Phase angle of Z
degree or radian
θ = −φ
φ
Phase angle of Y
degree or radian
φ = −θ
CS = −
2
2
XS
RS + X S
2
2
1
= C P (1 + D 2 )
ωX S
CP =
CS
B
=
ω 1+ D 2
LS =
X
Q2
= Lp
ω
1 + Q2
1
1
= L S (1 + 2 )
ωB P
Q
1
RP =
= R S (1 + Q 2 )
GP
LP = −
Q=−
1 X S BP
=
=
= tan θ
D RS GP
D=−
R
G
1
= S = P = tan(900 − θ ) = tan δ
Q X S BP
Notes:
1. f = frequency in Hertz; j = square root (-1); ω = 2πf
2. R and X are equivalent series quantities unless otherwise defined. G and B are equivalent parallel quantities unless otherwise defined.
Parallel R (Rp) is sometimes used but parallel X (Xp) is rarely used and series G (Gs) and series B (Bs) are very rarely used.
3. C and L each have two values, series and parallel. If no subscript is defined, usually series configuration is implied, but not necessarily, especially for C
(Cp is common, Lp is less used).
4. Q is positive if it is inductive, negative if it is capacitive. D is positive if it is capacitive. Thus D = -1/Q.
5. Tan δ is used by some (especially in Europe) instead of D. tan δ = D.
47
LCR Selection Guide
Feature
1659
1689/89M
1692
1693
1715 CE
1730 CE
Accuracy
(+/-)
Test Frequency
0.1% LCR
0.0005 DQ
0.02% LCR
0.0001 DQ
0.05% LCR
0.0003 DQ
0.02% LCR
0.0001 DQ
0.2% LCR
0.002 DQ
0.1% LCR
0.0001 DQ
100, 120, 1k, 10kHz
12Hz – 100kHz
12Hz – 200kHz
100, 120, 1k, 10kHz
Test Voltage
Monitor V/I DUT
Measured
Parameters
Measurement
Range
0.3V
No
L, C, R, D, Q
5mV – 1.275V
No
L, C, R, D, Q
100, 120, 1k, 10k &
100k Hz
0.3V and 1.0V
No
L, C, R, D, Q
.00001mH -99999H
.00001pF-99999mF
.00001 Ω-99999MΩ
.0001-9999
.00001mH-99999H
.00001pF-99999uF
.00001Ω-99999kΩ
1ppm-9999
.00001mH-99999H
.00001pF-99999mF
.00001Ω-99999MΩ
.0001-9999
0.25V and 1.0V
No
L, C, R, Z, D, Q, θ,
X
0.01uH-9.999kH
0.01pF-99.999mF
0.1mΩ-99.99MΩ
0.0001-9999
-180.00 ° - +180.00°
2, 4, or 8 meas/sec
Up to 50 meas/sec
2, 4, or 8 meas/sec
5mV – 1.275V
No
L, C, R, Z, D, Q, θ,
Y, G, X
.00001mH-99999H
.00001pF-99999uF
.00001Ω-99999kΩ
1ppm-9999
.00001° - 180°
.00001uS-99999S
Up to 50 meas/sec
100, 120, 1k, 10k,
20k, 50k & 100k Hz
10mV – 1.0V
Yes
L, C, R, Z, D, Q, θ,
X, ESR
0.001uH-99.999kH
0.001pF-9.9999F
0.01mΩ-99.99MΩ
0.0001-9999
-180.00 ° - +180.00°
Up to 25 meas/sec
Up to 62 meas/sec
Full 5 + 4 digits,
Bin #
No
No
2V INT
0 - 60V EXT
Built-In Kelvin plus
Optional fixtures
Full 5 + 4 digits,
Bin #, ∆, ∆%
No
No
2V INT
0 - 60V EXT
Built-In Kelvin plus
Optional fixtures
Full 5 + 4 digits,
Bin #, ∆, ∆%
No
No
2V INT
0 - 60V EXT
Built-In Kelvin plus
Optional fixtures
Full 5 + 4 digits,
Bin #, ∆, ∆%
No
No
2V INT
0 - 60V EXT
Built-In Kelvin plus
Optional fixtures
Full 5 + 4 digits
Bin #, ∆, ∆%
No
No
No
No
Kelvin Clips plus
Optional fixtures
Full 5 digit (pri/sec)
∆, ∆%, P/F, Bin#
No
No
0-5V INT with R BIAS
0 - 5V EXT
Kelvin Clips plus
Optional fixtures
Yes
Yes
Yes (10)
No
Yes (1 or 10)
No
Yes
Optional Cal Kit
Yes
No
Yes
No
Option
Option
No
No
25, 400, 6.4k, 100k
(Range dependent)
Yes
Yes
Yes (15)
Yes
Yes (1 – 256)
Yes
Yes
Optional Cal Kit
Yes
No
Yes
No
Option
Option
Yes
No
25, 400, 6.4k, 100k
(Range dependent)
Yes
Yes
Yes (10)
No
Yes (1 – 10)
No
Yes
Optional Cal Kit
Yes
No
Yes
No
Option
Option
Yes
No
25, 400, 6.4k, 100k
(Range dependent)
Yes
Yes
Yes (15)
Yes
Yes (1 – 256)
Yes
Yes
Optional Cal Kit
Yes
No
Yes
No
Option
Option
Yes
Yes
25, 400, 6.4k, 100k
(Range dependent)
No
Yes
Yes (8)
Yes
No
No
Yes
No
Yes
No
No
Yes
Option
Option
No
No
25, 100, 1k, 10k,
100k (DUT dependent)
No
Yes
Yes (8)
Yes
Yes (1-256)
No
Yes
No
Yes (50)
No
No
No
Yes
Yes
No
No
100/25, 100, 25, 10
(Constant current)
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Yes
Yes
Yes
No
No
Yes (0-10s)
Measurement
Speed
Display
Plot: F, V, I
Sequence
DC Bias Voltage
Test
Connection
Auto Parameters
Auto Range
Binning
Bin Sum
Averaging
Median Mode
Offset / Zero
Calibration
Save Setup
Floppy Drive
Self Diagnostics
RS232
IEEE-488
Handler Port
Constant V
Constant I
Source
Impedance (Ω)
Delta % (∆ %)
Delta LCR
D & Q in ppm
Ratio Display
Program Delay
Page 1 of 2
48
LCR Selection Guide
Feature
1910 CE
1920 CE
7400 CE
7600 CE
0.05% LCR
0.0005 DQ
0.18°
AutoAccTM
10Hz – 500kHz
20mV – 5.0V
250uA – 100mA
No
L, C, R, Z, D, Q, θ, Y,
G, B
0.001nH-99.9999H
0.01fF-9.9999F
0.0001mΩ-99.9999MΩ
.1ppm-99.9999 D
.1ppm-999999.9 Q
-180.000° - 180°
0.01uS-9.999999MS
0.05% LCR
0.0005 DQ
0.18°
AutoAcc TM
10Hz – 2MHz
20mV – 5.0V
250uA – 100mA
No
L, C, R, Z, D, Q, θ, Y,
G, B
0.001nH-99.9999H
0.01fF-9.9999F
0.0001mΩ-99.9999MΩ
.1ppm-99.9999 D
.1ppm-999999.9 Q
-180.000° - 180°
0.01uS-9.999999MS
Up to 40 meas/sec
Full 7 digit (pri/sec),
Bin #, Bin Sum,
∆, ∆%, Pass/Fail
Blank (No display)
Yes
Yes
0 - 2V INT
0 - 200V EXT
0 - 500V EXT 7400A
No
25 meas/sec
Full 7 digit (pri/sec),
Bin #, Bin Sum,
∆, ∆%, Pass/Fail
Blank (No display)
Yes
Yes
2V INT
0 - 200V EXT
0 - 500V EXT 7600A
No
Yes
Yes
Yes
4-BNC Guarded plus
Optional fixtures
Option
Yes
Yes (15)
Yes
Yes (1 – 1000)
Yes
Yes
Built-In Auto Cal
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
25, 400, 6.4k, 100kΩ
(Range dependent)
Yes
Yes
Yes
4-BNC Guarded plus
Optional fixtures
Option
Yes
Yes (15)
Yes
Yes (1 – 1000)
Yes
Yes
Built-In Auto Cal
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
25, 400, 6.4k, 100kΩ
(Range dependent)
Yes
Yes
Yes
No
Yes (0 – 1000ms)
No
Yes (0 – 1000ms)
No
Yes (0 – 1000ms)
Accuracy (+/-)
0.1% LCR
0.001 DQ
0.18°
0.1% LCR
0.001 DQ
0.18°
Test Frequency
Test Voltage
Test Current
Monitor V/I DUT
Measured
Parameters
Measurement
Range
20Hz – 1MHz
20mV – 1.0V
No
Yes
L, C, R, Z, D, Q, θ, Y,
G, B, ESR, DCR
0.001nH-99.999H
0.01pF-9.9999F
0.0001mΩ-99.999MΩ
0.00001-99.999 D
0.00000-9999.9 Q
-180.000° - 179.99 °
10nS-9999.9S
0.1mΩ-100kΩ DCR
Up to 40 meas/sec
Full 5 digit (pri/sec)
Engineering/Scientific
∆, ∆%, Pass/Fail
Blank (No display)
No
Yes
No
20Hz – 1MHz
20mV – 1.0V
No
Yes
L, C, R, Z, D, Q, θ, Y,
G, B, ESR, DCR
0.001nH-99.999H
0.01pF-9.9999F
0.0001mΩ-99.999MΩ
0.00001-99.999 D
0.00000-9999.9 Q
-180.000° - 179.99°
10nS-9999.9S
0.1mΩ-100kΩ DCR
Up to 40 meas/sec
Full 5 digit (pri/sec)
Engineering/Scientific
∆, ∆%, Pass/Fail
Blank (No display)
No
Yes
0 - 2V INT
0 – 1.0A INT
0 – 20.0A EXT (1320)
4-BNC Kelvin plus
Optional fixtures
Yes
Yes
No
No
Yes (1 – 1000)
Value of last 3 msmt
Yes
Built-In Auto Cal
Yes
No
Yes
Yes
Yes
Yes
No
Yes
No
5, 25, 50, 100Ω
No
4-BNC Kelvin plus
Optional fixtures
Yes
Yes
No
No
Yes (1 – 1000)
Value of last 3 msmt
Yes
Built-In Auto Cal
Yes
No
Yes
Yes
Yes
Yes
No
Yes
No
5, 25, 50, 100Ω
Yes
Yes
Yes
No
Yes (0 – 1000ms)
Measurement Speed
Display
Plot: F, V, I
Sequence
DC Bias Voltage
DC Bias Current
Test Connection
Auto Parameters
Auto Range
Binning
Bin Sum
Averaging
Median Mode
Offset / Zero
Calibration
Save Setup
Floppy Drive
Self Diagnostics
RS232
IEEE-488
Handler Port
Printer Port
Constant Voltage
Constant Current
Source Impedance
Delta % (∆ %)
Delta LCR
D & Q in ppm
Ratio Display
Program Delay
Page 2 of 2
49
LCR Accessory Selection Guide
Part #
1320-06
1320-07
Accessory
Description
36-pin Interconnect Cable (7000)
37-pin Interconnect Cable (1910)
150261
150262
150491
150566
150683
150710
7600
7400
1910
1920
1730
1715
1657-5995
1657-9600
1658-9620
1659-0120
1689-0120
1689-9600
1689-9601
1689-9602
1689-9604
1689-9605
1689-9611
1689-9630
1692-0120
1693-0120
Axial Lead Test Clips (4)
Extender Cable (3’) A/R to Banana
IEEE-Handler Interface
1659 Instruction Manual
1689 & 89M Instruction Manual
Remote Test Fixture
BNC Adapter Box
BNC/BNC Extender Cable (1 meter)
Cal Kit: 1659, 89, 89M, 92 & 93
Remote Fixture Strt & Go/NoGo LEDs
Rack Mount Kit: 1689M & 1693
High Speed IEEE/Handler Interface
1692 Instruction Manual
1693 Instruction Manual
1700-01
1700-02
1700-03
1700-04
1700-05
1700-07
1715-WZD
Axial/Radial Component Test Fixture
Remote Component Test Fixture
Kelvin Clip Leads (1 meter)
BNC/Banana to Alligator Lead Set
Chip Component Tweezers
Kelvin Clip Leads (2 meters)
1715 Virtual Front Panel
1900-WZD
Instruction
Instruction
Instruction
Instruction
Instruction
Instruction
1659
1689
1692
1693
Manual
Manual
Manual
Manual
Manual
Manual
Instrument
1715
1730
1910
1920
x
x
7400
x
7600
x
x
x
x
x
x
x
x
x
x
x
x*
x
x*
x
x*
x
x
x
x
x*
x
x*
x
x*
x (m)
x (m)
x
x
x
x*
x
x*
x
x*
x
x
x
x
x*
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
1900 Virtual Front Panel
x
x
2000-16
Rack Mount Flanges
x
x
7000-00
7000-01
7000-02
7000-03
7000-04
7000-05
7000-06
7000-07
7000-08
7000-09
Rack Mount Kit
BNC Cable Set (1 meter)
BNC Cable Set (2 meters)
Kelvin Clip Leads
Alligator Clip Leads
Chip Component Tweezers
Axial/Radial Test Fixture
Chip Component Test Fixture
High Voltage Test Fixture
Calibration Kit
x
x
x
x
x
x
x
700171
IEEE/Handler Interface
x*
x (m)
x*
x*
x
x
x*
x*
x*
x
x*
x*
x*
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
For Reference Only
*
This accessory requires the use of 1689-9601
(m)
This accessory for use with the 1689M Digibridge
The 1658-9620 is required for the 1689-9605 Start & Go/No Go LEDs to illuminate correctly.
Refer to: http://www.quadtech.com/products for a complete list of accessories by product including descriptions,
images and price information.
50
Application Note
Directory
51
QuadTech Application Notes
Contained herein is a list of QuadTech application notes available for download in Adobe PDF format.
To access the application notes visit: http://www.quadtech.com/resources and click on the Application
Note link.
A/N P/N
035000
035001
035002
035003
035004
035005
035006
035007
035008
035009
035010
035011
035012
035013
035014
035015
035016
035017
035018
035019
035020
035021
035022
035023
035024
035025
035026
035027
035028
035029
035030
035031
035032
035033
035034
035035
035036
035037
035038
035039
035040
035041
035042
035043
035044
035045
035046
035047
035048
035049
035050
035051
035052
035053
035054
035055
035056
035057
035058
035059
035060
Title/Description
Measuring Insulation Resistance of Capacitors
Series & Parallel Impedance Parameters and Equivalent Circuits
Equivalent Series Resistance (ESR) of Capacitors
Increasing Test Voltage on the QuadTech Digibridge
High Voltage DC Bias on the QuadTech Digibridge
Application for Precision Impedance Meters in a Standards Laboratory
Application for Precision Impedanc e Meters in a Standards Laboratory
Release
06-03-03
07-09-03
07-09-03
10-10-00
10-10-00
09-12-03
07-18-00
Application of DSP to Precision LCR Measurements
Measuring Biased Inductors with the 7000 Precision LCR Meters
A Guide to LCR Measurements
A Practical Guide to Dielectric Testing
Measurements of Dielectric Constant and Loss with the LD-3 Cell
Sentry Series Light Ballast Application
Guardian 1030S and Cable Reel Immersion Test
Guardian 1030 used for IR Test on Adhesive Heat Shrink
Sentry Series Panel Meter Application
07-09-03
07-25-03
07-10-03
06-24-03
08-04-03
10-03-02
10-03-02
10-03-02
10-03-02
Helpful Tips on Measuring Capacitors
Testing Capacitors with the QuadTech Model 1865 Megohmmeter/IR Tester
What’s Changing in Appliance Hipot Testing and Why
Measuring Biased Inductors with the QuadTech Digibridge
Characteristic Cable Impedance
Calibrating Impedance Meters Using Resistance Standards
Advanced Technique for Dielectric Analysis
Medical Equipment Test Applications using the 7000 Precision LCR Meter
Multi-Terminal Impedance Measurements (Why do these bridges use so…)
Testing Automotive Engine Oxygen Sensors using the 1900 Precision LCR
Hipot Testing of Motors and Safety Standard Compliance
Transformer Turns Ratio using the 7000 Series RLC Meters
The QuadTech 1865 as a Current Meter
Measuring Large Capacitors with the 1865-52 Component Test Fixture
Insulation Resistance of Cables
1865 Remote Pass/Fail Lights
1865 Specified Accuracy
The QuadTech 1865 Average Function
How to Connect a Foot Switch to the 1870 Dielectric Analyzer
The 1880 Specified Accuracy & Constant Current Ranges
External DC Supply for the 1536 Photoelectric Pickoff Cell
Basic Program to Control the Flash on a 1539 Strobe
Characteristic Cable Impedance
Constant Current with the 1693 RLC Digibridge
Charged Capacitor Protection Circuit for the QuadTech Digibridges
Transformer Ratio Measured Directly on the 1689 & 1693 Digibridges
How Much is One Joule
7000 Series Connections to the LD-3 Dielectric Cell
Digibridge Connections to the LD-3 Dielectric Cell
Battery Impedance Measurements
Charged Capacitor Protection for the 7000
What Voltage and Current is Applied to the Unknown?
Power Factor of a Capacitor (1900 Series)
Tutorial on Safety Standard Compliance for Hipot Testing
Benefits and Advantages of Digital Electrical Safety Testers
Measuring Electrical Properties of Copier/Printer Toners
Monitoring the Production Process of Tantalum Powder
Transducers used in Monitoring Nuclear Waste Tanks
Measuring the Dielectric Constant of PVC Compounds
Testing Animal Identification Implants
Testing Telecommunications Transformers
Enhanced Protection When Measuring Charged Capacitors
07-11-03
11-08-00
11-08-00
11-08-00
01-24-03
08-18-00
06-24-03
09-28-00
07-23-03
02-11-02
12-19-00
12-19-00
12-19-00
06-03-03
09-28-00
01-08-01
01-08-01
09-19-02
01-08-01
01-10-01
01-10-01
01-10-01
01-24-03
05-26-00
02-15-02
03-25-03
09-11-03
08-05-03
01-15-01
07-18-00
02-13-01
07-24-03
07-28-03
06-24-03
02-13-01
08-06-03
08-07-03
07-28-03
08-08-03
07-28-03
02-28-01
02-28-01
52
QuadTech Application Notes
A/N P/N
035061
035062
035063
035064
035065
035066
035067
035068
035069
035070
035071
035072
035073
035074
035075
035076
035077
035078
035079
035080
035081
035082
035083
035084
035085
035086
035087
035088
035089
035090
035091
035092
035093
035094
035095
035096
035097
035098
035099
035100
035101
035102
035103
035104
035105
035106
035107
035108
035109
035110
035111
035112
035113
035114
035115
035116
035117
035118
035119
035120
035121
035122
035123
Title/Description
Guardian 1000 Series Light Ballast Application
Cable Reel IR Testing Application
Adhesive Heat-Shrink IR Testing
Why Perform Electrical Safety Testing?
Ground Bond, Ground Continuity and Earth Continuity
Appliance Testing with the Guardian 6200 Production Safety Analyzer
Determining if a DUT is connected, using the Low Trip Limit (G1000 Series)
UL Standards
Guidelines for External Bias on the 7400 and 7600
Digibridge to 7000 Handler Conversion
Increasing Test Voltage of a 7000 Series RLC Meter
Mutual Inductance Measurements with a 4-Terminal LCR Meter
Connection of the 1865 Megohmmeter to a Resistivity Cell
Guardian 5000 Demo Guide
Guardian 2500 Demo Guide
Sentry 10-35 Demo Guide
Sentry 50 Demo Guide
Glossary of Electrical Safety Terms
Digibridge and Battery Impedance Measurements (1557, 1659, 1689, 1693)
Use of Palm Switches with QuadTech Hipot Testers
Measuring Transformer Turns Ratio using the 1910 Inductance Analyzer
Analyze This Inductor
So You Need To Measure Some Inductors…
LCR Product Accessories
EST Product Accessories
What’s Your LCR IQ?
Applying DC Bias to Inductors with the 1910 Inductance Analyzer
Applying DC Bias to Inductors with the 1910 and 1320
LCR & EST Product Interfaces
Electrical Safety Testing of Medical Electronic Equipment
Ensuring RH Sensor Repeatability with Capacitance Testing
Measuring IR with the Guardian 2530
Errors in Low Resistance Measurements
Building the Perfect Component Test Fixture
Custom Design Your Own Shock Therapy
Test Instrumentation: Can’t Always Get What You Want?
Guardian 2500 Series Features & Benefits
Sentry Series Features & Benefits
Overview of IEC 60601-1 Medical Electrical Equipment
Why Product Safety Test Your Electrical Medical Products?
Line Leakage Measurement & Human Body Equivalent Circuits
IEC60601-1 and Your Electrical Medical Products
A Bridge to the Future… Capacitance Measurements Through The Ages
What is the Accuracy Anyway?
25 Patents Reference Digibridge
Henry Hall: Father of the Digibridge
1920 Used in Eddy Current Sensor Testing
1689 Digibridge Used In Gas Sensor Materials Testing
Classification per IEC60601-1
EST 101 (IEC60601-1 Electrical Safety Tests)
Ensuring the Safety of Medical Electronics
Low ESR Capacitor Measurements
Measurement of Dielectric Constant and Loss: 1900 LCR Meter & LD-3 Cell
1900 Series Remote I/O Handler
Resistive Load Boxes for Hipot Testers and Megohmmeters
Guardian 6000 Series Scanner Connections
Leakage Current – Part 1
Leakage Current – Part 2
Calibration of 7000 Series Precision LCR Meters
Testing Power Line Filters using the Guardian 1030S
1864 Megohmmeter used in DC-10 Aircraft Maintenance
1864 Megohmmeter used in Aircraft Fuel Pump Inspection
National Deviations to IEC60601-1
53
Release
10-03-02
10-03-02
10-03-02
06-23-03
06-23-03
03-27-01
02-04-02
03-27-01
04-24-01
04-24-01
04-24-01
08-18-00
09-05-03
07-18-00
07-31-00
07-18-00
09-11-03
06-23-03
05-16-00
05-09-00
07-23-03
07-29-03
09-19-02
09-19-02
07-23-03
05-19-00
07-29-03
09-19-02
06-16-00
07-29-03
07-05-00
08-20-04
07-29-03
06-13-03
11-28-00
01-23-01
01-23-01
06-09-03
06-09-03
06-09-03
06-09-03
07-24-03
07-24-03
10-15-01
10-15-01
09-05-03
07-24-03
06-09-03
06-06-03
06-06-03
09-05-03
02-11-02
03-11-02
07-29-03
03-29-02
06-09-03
06-09-03
08-09-02
08-09-02
09-06-02
09-06-02
06-09-03
QuadTech Application Notes
A/N P/N
035124
035125
035126
035127
035128
035129
035130
035131
035132
035133
035134
Shared
035135
Shared
035136
Shared
035137
Shared
035138
Shared
035139
Shared
035140
Shared
035141
Title/Description
Ground Bond Testing per UL 60950
Connection of Isolation Transformer to Safety Tester
Dielectric Strength Testing of External Cardiac Defibrillators: IEC 60601-2-4
Testing Filter Capacitors on Medical Devices
Hipot Testing Multi-Conductor Feedthroughs used in Implanted Medical Devices
Digibridge Operation and Technique
Open and Short Correction
IR Testing Lithium Batteries for Medical Devices using the 1865 Megohmmeter
Using the 1900 LCR Meter for Medical Industry Capacitance Testing
Automated Quality Testing of Cathode Ray Tubes (CRTs)
A New Reliability Diagnostic for Aged Insulation Systems Based on Cure Monitoring of
“Motorettes” of Catalyzed Mica Tapes Wrapped on Aluminum Bars
– Courtesy of Donald R. Speer, W. J. Sarjeant
Determining Cure of a Varnish/Resin After Impregnation of an Electric Motor Stator or Transformer
– Courtesy of Donald R. Speer, W.J. Sarjeant, and Roger Ripley
Horizon – Marine Application, CableTest Application Note AN-146
– Courtesy of CableTest Systems Inc.
Mass HiPot Testing, CableTest Technical Bulletin TB-0110A
– Courtesy of CableTest Systems Inc.
High Current Source Compliance Limits, CableTest Technical Bulletin TB-0117
– Courtesy of CableTest Systems Inc.
MPT Horizon – Capacitance Measurement, CableTest Technical Bulletin TB-0118
– Courtesy of CableTest Systems Inc.
DC HiPot Description, CableTest Technical Bulletin TB-0119
– Courtesy of CableTest Systems Inc.
F-Type Leakage Measurements with the Guardian 6100
54
Release
06-13-03
05-15-03
09-05-03
09-05-03
09-05-03
09-12-03
09-15-03
09-15-03
09-17-03
01-23-04
04-07-04
04-07-04
04-07-04
04-07-04
04-07-04
04-07-04
04-07-04
06-14-04
Glossary
55
AC
Alternating current, an electric current that has one polarity during part of the cycle and the opposing polarity during the other part of the cycle. Residential electricity is
AC.
Capacitive Reactance
Measurement of the actual AC resistance of a capacitor.
How effective a capacitor is in allowing AC to flows
depends upon its capacitance and frequency.
Xc = 1/2πfC.
Accuracy
The difference between the measured value or reading
and the true or accepted value. The accuracy of an LCR
meter is typically given as a +/- percentage of the measured value for primary parameters and +/- an absolute
value for the secondary parameter. Example: +/-0.05%
for L, C & R and +/-0.0005 for Df.
Clearance
Clearance is the shortest distance between two conductors through air or insulating medium.
ANSI
American National Standards Institute, an industry association that defines standards for
data processing and communication.
Creepage
Creepage is the shortest path along the surface of an
insulator or insulating medium that separates two conductors. The insulator or insulation medium cannot be air.
Basic Accuracy
basic accuracy is specified at optimum test signal, frequency, highest accuracy setting or slowest measurement speed and impedance of the DUT. As a general
rule this means 1VAC RMS signal level, 1kHz frequency,
high accuracy which equates to 1 measurement/second
and a DUT impedance between 10Ω and 100kΩ.
CSA
Canadian Standards Association.
Compare
A procedure for sorting components by comparing the
component’s measured value against a known standard.
Current Draw
The mains current consumed by the product or DUT.
DC
Direct current, non-reversing polarity. The movement of
charge is in one direction. Used to describe both current
and voltage. Batteries supply direct current.
Binning
A procedure for sorting components into bins using
sequential limits or nested limits.
Delay Time
The amount of time an instrument waits before performing a task.
Breakdown
Failure of electrical insulation to provide a dielectric barrier to current flow.
Dielectric
A material which is an electric insulator or in which an
electric field can be sustained with a minimum dissipation
of power.
Capacitor
Abbreviated as C (as in LCR). A capacitor is a passive
component comprised of two conductors separated by a
dielectric. A capacitor stores charge, blocks DC flow and
allows AC flow based on frequency and capacitor design.
Dielectric Constant
Abbreviate K, relative dielectric constant. The dielectric
constant of a material is the ratio of the capacitance of a
capacitor filled with a given dielectric to that same capacitor having only a vacuum as a dielectric.
Capacitance
The ratio of charge on either plate of a capacitor to the
potential difference (voltage) across the plates. When a
voltage is applied, current flows immediately at a high
rate and then decays exponentially toward zero as the
charge builds up. If an ac voltage is applied, an ac current appears to flow continuously because the polarity of
the voltage is reversed at the frequency of the applied
voltage. The waveform of this current, however, is displaced in time from the applied voltage by 90°.
Discharge
The act of draining off an electrical charge to ground.
Devices that retain charge should be discharged after a
DC hipot or IR test.
DUT
Device Under Test - the product being tested.
56
DUT
Series
RS
Parallel
RS
CP
CS
LS
IMPEDANCE
Capacitive
Inductive
RP
or
GP
LP
RP
or
GP
ADMITTANCE
Capacitive
Inductive
Equivalent Circuit
Dwell Time
The amount of time the DUT is allowed to stabilize at the
test voltage before measurements are performed.
Ground
The base reference from which voltages are measured,
nominally the same potential as the earth. Also the side
of a circuit that is at the same potential as the base reference.
Electric Current
The flow of electrons (or electron "holes") through a conducting material, which may be a solid, liquid, or gas; the
rate of flow of charge past a given point in an electric circuit. The magnitude of current flow through the conductor is proportional to the magnitude of voltage or electrical potential applied across the conductor and inversely
proportional to the resistance (or impedance) of the conductor. Current is expressed in amperes or milliamperes
(amperes/1000).
Handler
Device for remote control of test instrument in component
handling operations.
Hertz
The unit of measure of frequency, equivalent to cycles
per second.
Equivalent Circuit
The configuration of the device under test. The components of the DUT can be represented as a series or parallel equivalent circuit.
High Limit
The upper value for a test to be considered a PASS. If
the measured value is higher than the high limit the test
is considered a FAIL. In hipot, leakage current and
ground bond tests a high limit is required.
Fall Time
The amount of time it takes to gradually decrease the
voltage to zero potential.
IEEE
An acronym for Institute of Electrical and Electronic
Engineers, a professional association of engineers.
Frequency
The rate at which a current or voltage reverses polarity
and then back again completing a full cycle, measured in
Hertz (Hz) or cycles per second.
IEEE 488
General Purpose Interface Bus (GPIB) - an industry standard definition of a parallel bus connection for the purpose of communicating data between devices.
GFCI
An acronym for Ground Fault Circuit Interrupter, a safety
device that breaks a power circuit as soon as it detects
current flow of a certain magnitude through the ground
return of a power circuit. Also known as GFI.
57
Impedance
A term used with alternating current circuits to describe
the "ac resistance" to the flow of current through a circuit
when an ac voltage is applied across the terminals of that
circuit. Impedance is a complex quantity composed of
real (in phase with voltage) and reactive (out of phase by
90°) components. Impedance is calculated as voltage
divided by current.
Low Limit
The lower value for a test to be considered a PASS. If
the measured value is lower than the low limit the test is
considered a FAIL.
Impedance (Z) is a vector summation of resistance (R)
and reactance (X).
Capacitors: Reactance = XC = 1/jωC
Milliohmmeter
An instrument designed to measure low values of resistance using a dc current or voltage.
Megohmmeter
An instrument designed to measure high values of resistance using a dc voltage usually greater than 50 V DC.
Inductors: Reactance = XL = jωL
Resistors: Resistance = R
Impedance = Z = square root (X 2 + R2 )
NIST
National Institute of Standards and Technology, an
agency of the U.S. Government that sets standards for
physical measurements and references, formerly called
the National Bureau of Standards.
Inductor
Abbreviated L (as in LCR). An inductor is a coil of wire. It
is used to create electromagnetic induction in a circuit.
NRTL
Acronym for Nationally Recognized Testing Laboratory,
such as Underwriters Laboratories (UL), Factory Mutual
(FM), or Canadian Standards Association (CSA).
Inductance
The property of a coil to oppose any change in current
through it. If the turns (coils) of the wire are stretched out,
the field intensity will be less and the inductance will be
less. Unit of measure is the Henry (H).
Offset
An automatic zeroing function to correct for leakage currents or additional resistance due to test leads or fixtures.
An offset is performed by making a measurement at the
programmed test settings, calculating the difference
between the leakage current or resistance measured and
the ideal current or resistance and then subtracting this
difference from all future measurements.
Inductive Reactance
A measure of how much the counter electro-magnetic
force (emf) of the coil will oppose current variation
through the coil. The amount of reactance is directly proportional to the current variation: XL = 2πfL.
Ohm's Law
The fundamental law of electrical circuits that describes
the relationship between voltage, current and impedance
(or resistance). For DC circuits, Ohm's Law states that
Current =Voltage/Resistance. For AC circuits, Current =
Voltage/Impedance. Stated conversely, Voltage = Current
x Resistance (DC) or Current x Impedance (AC). The difference between the dc resistance and ac impedance is
that ac circuits must deal with phase and time relationships and dc circuits do not.
Insulation
The protection against unwanted flow of current through
a path, as between a circuit of a product and the ground
reference. Materials that prevent current flow are referred
to as insulators or dielectrics.
Kelvin Connection
A circuit configuration that automatically compensates for
measurement errors caused by resistance of leads
between a tester and the point of measurement on a
DUT.
Ohms (Ω)
The unit of measure of resistance and impedance,
derived from Ohm's Law.
Level
The test signal level is the programmed RMS voltage of
the generator in an LCR meter. The actual test voltage
across the DUT is always less than the programmed
level.
OSHA
Occupational Safety and Hazards Administration, an
agency of the U.S. Government that regulates industrial
safety.
Load
The total resistance or impedance of all circuits and
devices connected to a voltage source.
58
Parameter
Electrical property being tested. The primary parameter
(L, C, R) is the first property characterized of the device
under test. The secondary parameter (D, Q, θ) is the second property characterized of the device under test.
Range
The resistance ranges the test instrument uses for reference in making the measurement.
Reactive
The component of an ac voltage, current, or impedance
that is 90° out of phase with the "real" or in phase component. Reactive components are associated with capacitive or inductive circuits.
Permittivity
Abbreviated ε. The dielectric constant multiplied by the
dielectric constant of empty space (εo), where the permittivity of empty space (εo ) is a constant in Coulomb’s
law, equal to a value of 1 in centimeter-gram-second
units and to 8.854 x 10 -12 farads/meter in rationalized
Real
The component of an ac voltage, current, or impedance
that is in phase with the "real" component. Real components are associated with purely resistive circuits.
meter-kilogram-second units.
Phase
The time relationships between alternating voltages, currents, and impedances. Usually expressed as complex
vectors with "real" (in-phase) and "reactive" (out of
phase) components.
Regulation
When applied to electrical circuits, regulation refers to the
variation in output voltage that occurs when the input
voltage changes or when the connected load changes.
When applied to test laboratories and agencies, refers to
the control exercised by these entities over test specs
and rules.
Polarization
A term used to describe a "one way" limitation on the
insertion of a plug into a receptacle for a corded product.
A polarized plug can be inserted in only one orientation
and cannot be reversed.
Repeatability
The difference between successive measurements with
no changes in the test setup or test conditions.
Potential
Electrical potential is a term equivalent to "voltage".
Reproducibility
Similar to repeatability but adds the element of what
could be expected under real life conditions.
Reproducibility would take into account the variability in
things like fixturing where the DUT being tested is
removed from the fixture and then inserted again.
Prefixes
The prefixes for Multiple Scientific Engineering Symbols
are:
1000000000000000
10 15
Peta
P
12
1000000000000
10
Tera
T
Giga
G
1000000
10 9
10 6
Mega
M
1000
10 3
Kilo
k
0.001
10 -3
milli
m
0.000001
10 -6
micro
µ
0.000000001
nano
n
0.000000000001
10 -9
10 -12
pico
p
0.000000000000001
10 -15
femto
f
1000000000
Resolution
The smallest value that can be shown on the display in a
digital instrument. LCR meters typically specify a measurement range that is the largest and smallest value that
can be shown on that meter’s display.
Resistance
The electrical characteristic that impedes the flow of current through a circuit to which voltage has been applied.
Resistance is calculated by Ohm's Law as voltage divid ed by current (for DC circuits). For AC circuits, it is the inphase or "real" component of impedance. Units are
expressed in ohms (Ω).
Protective Earth
Conductor that connects between any protectively earthed parts of a Class I product and an external protective
earth connection.
RS232
An industry standard definition for a serial line communication link or port.
Microsecond
One millionth of a second.
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Scanner
A scanner is a device designed to switch or matrix signals.
Waveform
The instantaneous value of a variable such as voltage or
current plotted against time.
SCC
The Standards Council of Canada, an agency of the
Canadian Government analogous to OSHA in the United
States.
X (Reactance)
Reactance is the imaginary component of Impedance.
Y (Admittance)
Admittance is the reciprocal of Impedance. Y = 1/Z
Speed
The rate at which the instrument makes a measurement
in measurements per second. Speed is inversely proportional to accuarcy.
Z (Impedance)
Impedance is the sum of alternating current oppositions
(capacitive reactance, inductive reactance and resistance). Z = R + jX
Spikes
A large momentary deviation from a normal voltage or
current waveform.
Stabilization Time
The time required for a transient disturbance to decay to
a steady state value.
Source Impedance
The impedance of the measuring instrument applied to
the input terminals of the device under test (DUT). If 1V
is the programmed voltage and the source impedance is
25 ohms, DUT is 25 ohms, then the voltage at the DUT is
0.5V.
Trigger
The device for initiating the test (applying the voltage or
current).
External Trigger
The test is initiated via an external source such as a
computer with an IEEE-488 or Handler interface.
One measurement is made each time the external
trigger is asserted on the handler.
Internal Trigger
The instrument continuously makes measurements.
Manual Trigger
The operator initiates the test by pressing the
[START] button. One measurement is made each
time the trigger is pressed.
QuadTech is a trademark of QuadTech, Inc.
Digibridge is a registered trademark of QuadTech, Inc.
Copyright 2002 by QuadTech, Inc.
4th Edition, February 2005, P/N 030122/A4
All rights reserved
Printed in U.S.A.
UL
Underwriters Laboratories, Inc., an NRTL located in
Illinois.
Voltage
The electrical potential applied to a circuit.
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