lab manual

lab manual
Electronics II
(EELE 3120)
(٢) ‫مختبر إلكترونيات‬
Lab Manual
Prepared by
Eng. Deeb Tubail
Eng. Amani Abu Reyala
IUG - 2009
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
ACKNOWLEDGMENT
We dedicate this work to our lovely teachers
Eng. Moayed Al-mobaied
Eng. Manhal Abu safer
Who put the keystone for this material
Eng. Deeb A. Tubail
Eng. Amani S. Abu Reyala
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Laboratory Safety
Experiments in this laboratory will be conducted in strict accordance with following
list of regulations, procedures and comments in order to promote a professional and
safe approach to the laboratory experience. Additionally, laboratory safety rules
apply during all experiments. If you are not sure of the operation of equipment or
laboratory procedure, particularly those which might compromise personal safety
and the safety of your laboratory partners, do not hesitate to ask your laboratory
instructor for assistance. The following rules must be strictly adhered to during the
course of your laboratory experiment:
1. Be calm and relaxed, while working in Lab.
2. No paper lying on table or nearby circuits.
3. No smoking, no food and no drinks permitted inside the laboratory.
4. Wear proper clothing and insulated footwear to the laboratory.
5. Do not use wet hands or stand on a wet floor while making electrical
connections.
6. Do not place personal belongings (books, coat, etc.) on the laboratory
equipment.
7. Keep your work area clean and organized.
8. Use only that equipment required for a particular experiment specified.
9. Do not use damaged or poorly insulated wires or equipment.
10. Properly ground all equipment.
11. Thoroughly check all connections before applying power.
12. Turn power off when making changes to your experiment.
13. Discharge capacitors by shorting with resistor.
14. Do not energize equipment until give permission.
15. Do not touch 120V electrical outlets or the terminals of any energized
electrical connection.
16. Report any accident to your instructor immediately.
17. Work deliberately and carefully.
18. In the event of a power failure, turn off the power switched to all equipment
immediately and wait further instructions.
19. After you are done with your experiment, turn all main switches off.
20. Failure to follow safety instructions can cause serious bodily injury or death.
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
The Islamic University of Gaza
Faculty of Engineering
Department of Electrical Engineering
Electronics II Laboratory (EELE 3120)
Laboratory Experiments:
The lab will cover the following experiments:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Multistage amplifier- cascade and cascode connection.
Multistage amplifier- current mirror and Darlington.
AC analysis of JFET.
Frequency response of BJT.
Frequency response of JFET.
Differential amplifier.
Operational amplifier- part 1.
Operational amplifier- part 2.
Power transistor.
Silicon controlled rectifier
Diac and Triac.
Objectives:
•
•
•
•
•
•
This course aims to give a practical view on your theoretical subject.
To be familiar with multistage amplifier connections.
To get to know the ac analysis of JFET.
To be familiar with the frequency response of BJT and JFET transistors.
To get to know operational and differential amplifiers
To be familiar with power transistors, SCR, Diac and Triac.
References: Robert L. Boylestad, Louis Nashelsky, “ Electronic Circuits, Devices
and Circuit Theory , ” 9th edi!on, Pren!ce Hall, 2006.
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Grades:
Lab work……………………….
10 Pts
Midterm Exam………………....
20 Pts
Final Exam………………….....
30 Pts
Reports…………………………
15 Pts
Prelabs…………………………
5 Pts
Project
20 Pts
Lab Policy:
•
•
•
•
No late reports or pre-labs will be accepted
Avoid copy-paste Technology
Reports should be done individually.
Mid term Exam will be at the end of Lab(5)
Office Hours: Open-door policy, by appointment or as posted.
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
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PSpice with OrCAD Capture
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Objectives :
Provide an introduction to the basics of using the PSpice circuit analysis
software package.
Get a review about installing of OrCAD software program.
Be familiar with different types of analyses and simulation.
Introduction:
PSpice is a powerful general purpose analog and mixed-mode circuit simulator that
is used to verify circuit designs and to predict the circuit behavior. Its name implies '
Simulation Program for Integrated Circuits Emphasis ' .
It is recommended to simulate all circuits you will connect in the lab to get the ability
of predicting the practical results thus the intended ideas become more obvious.
PSpice allows you to do different types of analysis according to the purpose of each
circuit. These types are DC bias, DC Sweep, Transient with Fourier analysis, AC
analysis, Parameter sweep and Temperature sweep.
In this lab, we will use three basic types of circuit analysis; transient analysis, AC
frequency sweep and DC sweep. Briefly, these may be described as follows:
The “DC sweep” analysis produces a graph of the voltage (or current) at a
selected point in the circuit as the value of one of the DC sources in the circuit
is swept over some range.
The “AC Sweep” analysis produces a graph of the magnitude of the
sinusoidal voltage versus frequency at a selected point in the circuit.
The “Time Transient” analysis produces a graph of the output voltage (or
current) versus time at a selected point in the circuit. Applied sources are
characterized by a time sequence of samples of a voltage or current
waveform.
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Procedure :
1. Install OrCAD Program on your computer from your own CD. Try to follow
the instruction of downloading.
2. from ʹ Programsʹ directory, click : OrCAD release 9, Capture CIS. The main
page of OrCAD will appear.
3. To open anew project, click : File, New, Project.
4. In the dialog box, type the name of your project. Check the ʹ Analog or Mixed
– Signal Circuit Wizard ʹ . Browse to the path to be used to store the project at
location Field. Click OK.
5. Another dialog box will appear, it asks you to add libraries you need at your
project. Initially the default libraries are sufficient so Click Finish.
6. A schematic page will appear. Click near the right edge of the screen Then a
tool bar should appear.
Simulation Examples:
As mentioned before, there are different types of analysis are available using
OrCAD, in this laboratory, you will work through an example of each of the three
basic types of analysis.
•
DC sweep :
1. Open OrCAD main window, Open a new project .
2. From the tool bar, click ʹ Place partʹ.
3. From source library, choose VDC "Dc source" and click ok. Place it on your
project page.
4. From Analog library, choose R "resistor" and click ok. Place two resistors on
the project page.
5. From tool bar, click ʹ Place wireʹ and connect between the components as
shown at figure(1).
6. From the tool bar, click ʹ Place groundʹ, choose ʹ 0/SOURCEʹ, connect it to the
circuit as shown at figure (1).
7. Save your project.
8. click PSpice, New simulation profile, Type your desired name of the
simulation name. Click OK.
9. Simulation Settings window will appear. Choose ʹ DC Sweep ʹ as the analysis
type.
10. Choose the type of the dc source you want to draw the output with respect to
it . At this example it is a voltage source. Type its name V1.
11. Type the range of V1, start value, final value and increment which is the step
between voltage values.
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Figure (1) : DC sweep example circuit
12. It is intended to plot the current versus to the value of voltage source, so the
current should be measured. Put ʹCurrent into Pinʹ as shown at figure (1)
13. click Runʹ. The result of simulation will appear as shown at figure(2).
Figure (2) : DC sweep simulation result
14. Try to analyze and explain the result, does it as you have predicted ….. ?!!
15. For any details, see ʹ Example1 ʹ video file on the aJached CD.
•
AC sweep :
1. Try to follow the same steps at ʹExample1ʹ, to build the circuit shown at
figure(3).
2. The differences between two examples are:
- Use VAC ʺac sourceʺ source instead of VDC, change its value to 1V.
Ac source is used for plotting relations versus frequency.
- Use ʹVoltage levelʹ instead of ʹCurrent into Pinʹ, to plot the output
voltage versus frequency.
- Choose ʺAC Sweepʺ as an analysis type for this example, linear choice.
Type the range of frequency at start frequency, end frequency and
total points.
- Note that the x-axis variable is the frequency while at dc sweep is the
source voltage V1.
- The result of AC sweep simulation is shown at figure(4).
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Figure (3) : AC sweep example circuit
Figure (4) : AC sweep simulation result
•
Time Transient :
1. Follow steps at ʹExample2 ʹ to build the circuit shown at figure(5).
2. The differences are:
- Use VSIN ʺsinusoidal sourceʺ source instead of VAC. The sinusoidal
source is used for plotting relations versus for time.
- Double click on the sinusoidal source to change its parameters:
frequency, amplitude and offset voltage.
- Choose ʺTime transientʺ as an analysis type for this example. Type the
duration of simulation you want. Keep it suitable with the frequency
of the sinusoidal input to get obvious simulation result.
- Note that the x-axis variable is the time.
- Showing the input and output signals in the simulation result helps
you during results analysis.
- The result of AC sweep simulation is shown at figure(6).
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Figure (5) : Time transient example circuit
Figure (6) : Time transient simulation result
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
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Laboratory Instruments and Measurements
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Objectives:
•
•
To learn how to make basic electrical measurements of current, voltage, and
resistance using multi-meters.
To be familiar with the bread board.
Theoretical Background:
Definitions:
a- Electric current (i or I) is the flow of electric charge from one point to another,
and it is defined as the rate of movement of charge past a point along a
conduction path through a circuit, or i = dq/dt. The unit for current is the
ampere (A). One ampere = one coulomb per second .
b. Electric voltage (v or V) is the "potential difference" between two points, and
it is defined as the work, or energy required, to move a charge of one
coulomb from one point to another. The unit for voltage is the volt (V). One
volt = one joule per coulomb.
c.
Resistance (R) is the "constant of proportionality" when the voltage across a
circuit element is a linear function of the current through the circuit element,
or v = Ri. A circuit element which results in this linear response is called a
resistor. The unit for resistance is the Ohm(Ω . One Ohm = one volt per
ampere. The relationship v = Ri is called Ohm's Law.
Typical standard resistor values are 1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6,
6.8, 7.5, 8.2, and 9.1 multiplied by a power of 10
d.
Electric power (p or P) is dissipated in a resistor in the form of heat. The
amount of power is determined by p=Vi, p=i2R, or p=v2/R. The latter two
equations are derived by using Ohms Law (v = Ri) and making substitutions
into the first equation. The unit for power is the watt (W) One watt = one
joule per second.
Instruments and equipments that will be used in this lab:
1- Multimeter:
Meters are used to make measurements of the various physical variables in
an electrical circuit. These meters may be designed to measure only one variable
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
such as a voltmeter or an ammeter. Other meters called multimeters are
designed to measure several variables, typically voltage, current and resistance.
These multimeters have the capability of measuring a wide range of values for
each of these variables. Some multimeter operate on battery power and are
therefore easily portable, but need battery replacement. Others operate on A.C.
power.
The read-out, or display, of value being measured on the multimeter may be
of the digital type or the analog type. The digital type displays the measurement
in an easy to read form. The analog type has a pointer which moves in front of a
marked scale and must be read by visually interpolating between the scale
markings.
In this lab we will use a digital multimeter which is as shown in figure 1.
Figure (1) : The multimeter device
It consists of :
-
Ammeter which is used to measure A.C or D.C current passing in a branch
and is connected in series with the circuit’s elements.
-
Voltmeter for measuring the A.C or D.C voltage drop a cross any two point
in the circuit, and is connected in parallel.
-
Ohmmeter for measuring the resistance, and is connected across the resistant.
2- Oscilloscope:
An oscilloscope (abbreviated sometimes as 'scope or O-scope) is a type of
electronic test instrument that allows signal voltages to be viewed, usually as
a two-dimensional graph which a potential differences plotted as a function
of time. Although an oscilloscope displays voltage on its vertical axis, any
other quantity that can be converted to a voltage can be displayed as well.
Oscilloscopes are commonly used when it is desired to observe the exact
wave shape of an electrical signal. In addition to the amplitude of the signal,
an oscilloscope can show distortion and measure frequency, time between
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
two events (such as pulse width or pulse rise time), and relative timing of two
related signals. (figure2.2)
Figure (2) : Oscilloscope
3- Wattmeter
The wattmeter is an instrument for measuring the electric power in watts of
any given circuit. The traditional analog wattmeter is an electrodynamics
instrument. The device consists of a pair of fixed coils, known as current coils,
and a movable coil known as the potential coil.
The current coils connected in series with the circuit, while the potential coil
is connected in parallel.
A current flowing through the current coil generates an electromagnetic field
around the coil. The strength of this field is proportional to the line current
and in phase with it. The potential coil has, as a general rule, a high-value
resistor connected in series with it to reduce the current that flows through it.
The result of this arrangement is that on a dc circuit, thus conforming to the
equation W=VA or P=VI. (figure 3)
Figure (3) : Wattmeter
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
4- Bread Board:
A breadboard is used to make up temporary circuits for testing or to try out
an idea. No soldering is required so it is easy to change connections and
replace components. Parts will not be damaged so they will be available to reuse afterwards.
This is in contrast to strip board and similar prototyping printed circuit
boards, which are used to build more permanent soldered prototypes, and
cannot easily be reused.
A typical small bread board is shown in figure below(figure 4), which is
suitable for testing a small circuit.
Figure (4) : The bread board
Connections on Breadboard
Breadboards have many tiny sockets (called ʹholesʹ) arranged on a 0.1ʺ grid. The
leads of most components can be pushed straight into the holes. ICs are inserted
across the central gap with their notch or dot to the left.
Wire links can be made with single-core plastic-coated wire of 0.6mm diameter (the
standard size). Stranded wire is not suitable because it will crumple when pushed
into a hole and it may damage the board if strands break off.
The diagram shows how the breadboard holes are connected:
The top and bottom rows are linked horizontally all the way across as shown in
figure (5), it is suggested to use the horizontal holes ; one for the positive power
supply and the other for ground also the lower horizontal holes may be used for a
negative power supply.
The other holes are linked vertically in blocks of 5 with no link across the centre.
Notice how there are separate blocks of connections to each pin of ICs.
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Figure (5) : bread board connections
On larger breadboards there may be a break halfway along the top and bottom
power supply rows. It is a good idea to link across the gap before you start to build a
circuit, otherwise you may forget and part of your circuit will have no power!
Lab Work:
Building a Circuit on Breadboard
1. Connect the circuit shown in figure (6) on the bread board.
2. Set the power supply output voltage to 10v.
3. Find the value of the current passing through the circuit and the voltage
across the resistor using multi-meter.
4. Record the value that you got in the table 1.
A
10V
1k
V
Figure (6)
V(volt)
I(mA)
Table (1)
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Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
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Experiment 1
Multistage Amplifier – Part 1
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Objectives:
Investigate the multistage amplifier design using simple BJT amplifier circuit,
especially cascade and cascade connections practically and by simulation
Prelab:
Consider the circuit shown in figure 2 and using OrCAD Pspise:
1. Connect the first stage amplifier without AC input (only DC), then find and
plot 1st transistor Q-point (Ic and Vce).
2. Like one, find and plot the Q-point of the 2nd transistor.
3. Now connect the multistage circuit with sinusoidal input (50mV, 1 kHz).
4. Plot the input voltage, 1st stage output voltage, 2nd stage voltage. " Don't plot
the signals on the same graphs".
5. Let the output of the first stage on the emiJer (VE1), the second output on the
collector and then plot the input voltage, 1st stage output voltage, 2nd stage
voltage. " Don't plot the signals on the same graphs".
6. Let the output of the first stage on the emiJer (VE1), the second output on the
emiJer (VE2) and then plot the input voltage, 1st stage output voltage, 2nd
stage voltage. " Don't plot the signals on the same graphs".
7. Comment on your results at (4, 5, and 6).
Theoretical Background:
The properties of BJT amplifiers can be summarized in table(1).
These basic amplifier stages can be combined by cascade connection or cascode
connection to create multistage amplifiers with better overall characteristics.
•
Cascade connection :
In which each stage is coupled with the next by a capacitor. Figure (1) shows a
general model for a cascade multistage amplifier configuration.
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
Common emitter
ENG.DEEB ASAD TUBAIL
CE with RE
Emitter follower CC
Construction
V1
V1
0
V1
0
0
R2
R1
C1
R1
R1
C1
C1
0
0
0
Voltage gain
High
Medium
Low
Input resistance
Low
High
High
Output resistance
High
High
Low
Table (1) : Properties of BJT amplifiers
Figure (1) : General model for a cascade multistage amplifier
The gain of multistage amplifier is the product of the individual gain stages. For the
generalized example in figure (1), the over all gain can be calculated as :
Av(total) = Av1 . Av2 . Av3
----------------------- (1)
The input resistance of the multistage amplifier equals to the input resistance of the
first amplifier stage as following:
Rin(total) = Rin1
--------------------------------------- (2)
And the output resistance will be
Rout(total) = Rout3 --------------------------------------- (3)
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
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These properties will help us to design a multistage amplifier that has high gain,
high input resistance and low output resistance by carefully combining the basic BJT
amplifier stages.
•
Cascode connection :
In which the collector of the leading transistor is connected to the emitter of
the following transistor as shown at figure (3). The cascode connection offers
high gain, high stability, and high input impedance.
Lab Work:
For the circuit shown in figure (2) :
1. Evaluate the DC Q-point for each transistor.
2. Connect the multistage circuit, plot the output voltage using (50 mV, 1k Hz)
sinusoidal input. Then determine the voltage gain.
3. Let the output of the first stage on the emitter, plot the output voltage and
determine the voltage gain.
4. Let the output of the second stage on the emitter, plot the output voltage and
determine the voltage gain.
5. Comment on your result.
V1
0
15V
R3
1k
R1
10 k
100u
R6
1k
C2
Q1
C1
R5
10k
C3
22u
Q2
Q2N2222
100u
Q2N2222
R9
1.8 k
V2
R2
1k
0
R7
1k
R4
100
0
Figure (2) : Cascade multistage circuit
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R8
47
0
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Exercises :
1. Calculate the DC Q-points for each transistor shown in the circuit in
figure (2), assume that β =100
2. Derive Zin, Av, Zout for the circuit in figure (2).
3. Simulate the circuit shown at figure (2) and figure (3).
V1
0
15 V
R3
1k
C2
R5
22k
C4
R1
R6
10k
22u
10u
Q2N2222
22k
Vin
f =1kHz
0
C1
100u
Q2N2222
R2
10k
R4
470
0
0
Figure (3) : Cascode multistage circuit
١٩
C3
10u
Vout
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
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Experiment 2
Multistage Amplifier – Part 2
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Objectives:
Investigate another types of the multistage amplifier design using simple BJT
amplifier circuit, which are current mirror connection and Darlington connection
practically and by simulation.
Theoretical Background:
1. Current mirror connection:
A current mirror may be through of as an adjustable
current regulator. The current limit being easily set by
a single resistance. In this lab one of these circuits will
be built. Also exploring regulating properties and
experience some of its practical limitations. Current
mirror circuit is shown in figure (1).
Figure (1) : Current mirror
2. Darlington connection:
A very popular connection of two bipolar junction transistors for operation as one
transistor. The main feature of it is that the composite transistor acts as a single unit
with a current gain that is the product of the current gains of the individual
transistors, that:
βD = β1 * β2
where βD is the current gain of the Darlington circuit, β1 is the current gain of the
first transistor and β2 is the current gain of the second transistor. Basic circuit of th
Darlington transistor is shown in figure (2).
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ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Figure (2) : Darlington transistor
Lab Work:
Part 1: Current mirror:
-
Measurement of βf :
First a quick assessment will be made of the degree of electrical match
between two BJTs which will be used in the current mirror circuit. Using the
circuit shown in figure (3), do the following procedure :
12V
0
0.1u
220 k
3.3 k
Q1
0V
Vdc
0
Figure (3) :
βf test
1. Increase VDC from zero till you obtain VCE = 0.2 V, this value should be
regarded as VDC1. The value of VDC should then increase to obtain VCE =
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1.5 V. This value of VDC should be recorded as VDC2. Then the vale of βf
can be obtained as:
2. Repeat the above procedure for Q2.
3. Comment on the degree of match in βf for the two transistors
-
Operation of current mirror:
0
12V
12.00V
330
R9
7.345V
R10
500
I
500
RL
R6
470
I
1000
Q3
Q4
6.043V
6.043V
R7
R8
I
500
86.55mV
I
500
Q5
Q6
714.9mV
Q2N2222
Q2N2222
Q2N2222
Q2N2222
0V
0
Figure (4) : current mirror circuit
1. Build the circuit shown in figure (4).
2. Calculate the value of IREF.
3. Let the load resistance equal to 1 kΩ, then measure Ie1 and Ie2. Are they
nearly equal? Are they nearly to Iref? Summarize your result in table(1).
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Calculated Iref
Measured Ie1
Measured Iref
ENG.DEEB ASAD TUBAIL
Measured Ie2
Calculated Ie2
Table (1)
4. Let the load resistance equals to 2 kΩ and measure Ie2 and Vce2. Repeat the
measuring for RL = 3 kΩ and 13 kΩ. Record your results in table (2).
RL= 1 kΩ
RL= 2 kΩ
RL= 3 kΩ
RL= 13 kΩ
Meas. Ie2 (mA)
Meas. Vce2 (V)
Table (2)
Part 2: Darlington transistor:
0
18V
3.3 M
Vi
0.5 u
Vo
0.5 u
390
0
Figure (5): Darlington emiJer follower circuit
6. Connect the circuit shown in figure (5).
7. Measure the dc bias voltages and currents.
8. Evaluate the measured DC Q-point for each transistor.
9. Plot the output voltage using (50 mV, 1k Hz) sinusoidal input. Then
determine the voltage gain.
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Exercises :
1. Calculate the DC Q-points for each transistor shown in the circuit in
figure (5).
2. Derive Zin, Av, Zout, Ai for the circuit in figure (5).
3. Simulate all circuits of this laboratory experiment.
4. Comment on your results.
Note :
you can get the value of β and ri of your Darlington transistor from its data
sheet.
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Experiment 3
AC analysis of JFET
‫ــــــــــــــــــــــــــــــــــــــــــــــــــ‬
Objectives:
•
Revise the dc analysis of JFET circuits.
•
To bias the JFET.
•
To understand JFET AC model.
•
To make JFET amplification.
Pre-lab:
Referring to figure (1), design a common source configuration that has an operating
point ( IDQ = 4mA, and Vout = 10V).
Theoretical background :
Bipolar junction transistors have low input impedance, small high frequency gain
and are non linear when |VCE| < 0.2 V. The input impedance is naturally restricted
by the forward-biased base-emitter junction. There are always problems due to the
main charge carriers passing through the region where the majority carriers are of
opposite polarity.
The field effect transistor (JFET) overcomes some of the problems of the bipolar
junction transistor. JFETs come in two types : N- channel and P- channel.
The designation refers to the polarity of the majority charge carriers in the bar of
semiconductor that connects the drain terminal D to the source terminal S. Since the
channel is formed from a single polarity (unipolar) material, its resistance is a
function only of the geometry of the conducting volume and the conductivity of the
material. The JFET operates with all PN junctions reverse-biased so as to obtain a
high input impedance into the gate.
Common Source Configuration :
The common source configuration for a FET is similar to the common emitter bipolar
transistor configuration and is shown in figure(1). The common source amplifier can
provide both a voltage and current gain. Since the input resistance looking into the
gate is extremely large the current gain available from the FET amplifier can be large
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but the voltage gain is generally inferior to that available from a bipolar device. The
source by-pass capacitor is connected to provide a low impedance path to ground for
high frequency components. As a result of presence of by-pass capacitor, AC signals
wi11 not cause a swing in the bias voltage.
Since the FET gate current is small we can make the approximations iD=is and
Vg=Vgs: the source is positive with respect to the gate for reverse bias.
Figure (1): Common source configuration
Note: Donʹt forward bias JFET gate, forward gate current larger than 50 mA will
burn out the JFET.
Lab Work:
Part 1: JFET Biasing:
1. Refer to figure (1) use VDD = 14V.
2. Operating point IDQ = 4mA and Vout = 10 V.
3. Set RG = 1M ohm (or 2M ohms).
4. Place Rd with the value calculating in the pre-lab to get the desired operating
point.
5. Adjust the value of Rs until it matches the calculated value.
6. Switch the power on and confirm the Q-point, try to tune Rs until IQis close
as possible to 4mA.
7. Summarize your measurements in table (1).
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IDQ
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Vout
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VDSQ
Rs
RD
Table (1)
Part 2: JFET Amplification:
14V
0
Rd
C2
Rs ource
C1
Vout
10u
10u
Rg
V1
Rs
0
Function Generator
Figure (2)
1. Refer to figure (2).
2. Apply AC sine wave from the function generator (100mV p-p at 1KHz).
3. Observe the input and output signal on the oscilloscope.
4. Vary the amplitude of AC input as shown in table (2).
5. Record the corresponding parameters using the voltmeter.
6. Plot the input and the output signal on the same paper.
7. Connect the RL = 10k and measure Av, Avs, Ro.
8. Shunt Rs with 10uF capacitor, put AC signal 100mV p-p and observe the
output voltage on the oscilloscope.
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Vin(t) 1kHz (rms)
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Vg(t) Iout Vout(t) Ro=Vout/Iout
Distortion
Av
Avs
0.5
1
2
3
4
5
Table (2)
Exercises:
1. For the circuit in figure (1), Find JFET power and compare your result with
data sheet.
2. For the circuit of figure (2), Does the output voltage increases or decreases
compared with first steps? Why?
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Experiment 4
Frequency Response of BJT
‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬
Objectives:
To study the frequency response and bandwidth of the common emitter CE-BJT, the
common collector CC-BJT, and the common base CB-BJT amplifiers.
Theoretical Background:
The frequency response is a representation of the system's response to sinusoidal
inputs at varying frequencies. The output of a linear system to a sinusoidal input is a
sinusoid of the same frequency but with a different magnitude and phase. It is
defined as the magnitude and phase differences between the input and output
sinusoids. It is the measure of any system's output spectrum in response to an input
signal.
The frequency response allows you to determine how the system responds at
different frequencies, finds the stability properties of the system and designs the
appropriate controllers for the system according to required specifications.
Bandwidth is typically measured in hertz, It is the difference between the upper and
lower cutoff frequencies of a filter, a communication channel, or a signal spectrum. In
case of a low-pass filter or baseband signal, the bandwidth is equal to its upper cutoff
frequency. The term baseband bandwidth refers to the upper cutoff frequency.
•
Low frequency response of BJT amplifier :
The low cutoff frequency is determined by Cs is given by the relation:
fLs =
where
1
2 Π ( Rs + Ri )Cs
Ri = R1 II R2 II β re
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The low cutoff frequency is determined by Cc is given by the relation :
fLc =
where
1
2 Π ( Ro + RL )Cc
Ro = Rc II ro
The low cutoff frequency is determined by CE is given by the relation :
fLE =
1
2 Π Re Cc
R s

+ re 
Re = REII 
 β

\
where
Rs'=Rs ||R1||R2
•
High frequency response of BJT amplifier :
fHi =
where
1
2ΠRThiCi
RThi = Rs II R1 II R2 II Ri
Ri = R1||R2||Bre
Ci = Cwi + Cbe + CMi = Cwi + Cbe + (1 – Av )C bc
Re=15.76 ohm
B=100
Av= ( -Rc||RL)/re
fHo =
where
1
2 Π R Tho C o
RTho = Rc II RL II ro
Co = Cwo + Cce + CMo
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Lab work :
1) Connect the circuit in figure 2.
2) Adjust the DC power supply at 20 V.
3) Adjust the function generator to sinusoidal of amplitude 1 V at a frequency at
1 kHz.
4) Measure the output voltage Vo.
5) Decrease the frequency till Vo = 0.707 Vo, Find fL.
6) Increase the frequency till Vo = 0.707 Vo, find fH.
7) Calculate the bandwidth (BW).
8) Vary the frequency according to table 1 and complete the table.
9) Plot the voltage gain against frequency.
10) Repeat above procedures for the circuit at figure 3 and complete table (2).
20 Vdc
3.3 k
R1
R3
47 k
C2
C1
Q1
V1
R5
1k
Q2N2222
10u
1 Vac
1u
R2
R4
10 k
1k
C3
20u
0
0
Figure (2) : Common Emitter amplifier
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0
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Frequency (Hz)
Electronics II
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Vi (volt )
Vo (volt)
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Av =Vo/Vi
1
10
100
1k
5k
10k
50k
100k
1M
Table (1) : CE results
20 Vdc
3.3 k
R1
R3
47 k
Q1
C1
Q2N2222
10u
V1
1 Vac
R2
R4
10 k
1k
C2
1u
R5
4.7 k
0
0
Figure (3) : Common Collector amplifier
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Frequency (Hz)
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Vi (volt )
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Vo (volt)
Av =Vo/Vi
1
10
100
1k
5k
10k
50k
100k
1M
Table (2) : CC results
Exercises :
1) Repeat all steps for figure 2 using OrCAD.
2) Repeat all steps for figure 3 using OrCAD.
3) Simulate the circuit at figure 4 to get its frequency response.
Figure (4) : Common Base amplifier
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Experiment 05
JFET Frequency Response
‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬
Objectives:
•
To analysis the FET amplifier in low & high frequencies to show and realize
the response.
•
To find the cut off frequencies and calculate bandwidth.
Theoretical Background:
1. Low frequency response- FET amplifier
The FET amplifier in low frequency is quite similar to that in BJT.
The low cutoff frequency is determined by CG is given by the relation:
f
LG
=
1
2π (R sig + R i )C G
The low cutoff frequency is determined by Cc is given by the relation :
f
LC
=
1
2π (R o + R L )C
C
The low cutoff frequency is determined by Cs is given by the relation :
f
LS
=
1
2π R eqC
S
Where
Ri =RG
Ro =RD
Req=Rs //(1/gm)
After calculation we choose the largest frequency as cutoff frequency.
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V1
20V
RD
R4
4.7k
0
R1
C2
C1
0.5u
J1
Cc
10k
V2
Vs
R5
0.01u
Rsig
RL
J2N3819
CG
Cs C3
RG
2.2k
R2
2u
1000k
RS
R3
1k
0
Figure (1) :low frequency FET
2. High frequency response- FET amplifier
In high frequency there are parasitic capacitances (Cgd , Cgs , Cds) and wiring
capacitances (Cwi , Cwo) .
For the input circuit the high cutoff frequency is determined by the relation:
f
Hi
=
1
2π R ThiC
i
For the output circuit the high cutoff frequency is determined by the relation:
f
Ho
=
1
2π R ThoC
o
Where:
RTHI =Rsig//RG
Ci =CWi + Cgs + CMi
CMi=(1-Av ) Cgd
RTHo=RD//RL//rd
Co=CWo +Cds +CMo
CMO= (1-(1/Av))Cgd
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Av=Vo/Vi= -gm(Rd//RL)
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V1
20V
RD
R4
4.7k
0 Cgd C7
Cc
C2
Vo
Rsig
R1
Vs
V2
10k
CG
C1
2p
0.5u
J1
Cds
0.01u
Cwi
RG
R2
J2N3819
C8
C4
5p
1000k
Cwo
C5
0.5p
6p
C6
R5
RL
C3
2u
Cgs 4p
R3
Rs
Cs
1k
0
Figure (2) : high frequency FET
Lab work :
1) Connect the circuit in figure 1.
2) Adjust the DC power supply at 20 V.
3) Adjust the function generator to sinusoidal of amplitude 1 V at a frequency at 1
kHz.
4) Measure the output voltage Vo.
5) Decrease the frequency till Vo = 0.707 Vo, Find fL.
6) Increase the frequency till Vo = 0.707 Vo, find fH.
7) Calculate the bandwidth (BW).
8) Vary the frequency according to table 1 and complete the table.
9) Plot the voltage gain against frequency.
10) Repeat above procedures for the circuit at figure 2 and complete table (2).
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Frequency (Hz)
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Vi (volt )
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Vo (volt)
Av =Vo/Vi
Vo (volt)
Av =Vo/Vi
1
10
100
1k
5k
10k
50k
100k
1M
Table (1)
Frequency (Hz)
Vi (volt )
1
10
100
1k
5k
10k
50k
100k
1M
10M
15M
Table (2)
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Exercises :
For figure1& figure2 :
1.
calculate the cutoff frequencies using equations (mathematically)
2.
Repeat all steps using ORCAD.
3.
compare between result that you had got from exercise and compare
with result you had got from practical experience.
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‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬
Experiment 6
Differential Amplifier
‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬
Objective:
In this laboratory experiment you will construct and test the differential amplifier
using BJTs.
Theoretical Background:
The differential amplifier is a basic circuit, used in all linear integrated circuits. It is
also the basis for analog to digital and digital to analog converters. Understanding its
operation including the DC bias operation and its response to signal inputs are
important for further study of linear integrated circuits.. The differential mode gain
is Avdm and the common mode gain is Avcm. The differential amplifier circuit is
shown in figure (1).
0
15 V
1k
1k
10k
10k
Vin1
Vin2
1k
15V
0
0
0
Figure (1) : Differential amplifier circuit
Lab Work:
1. Construct the circuit shown in figure (1). Make the circuit quiescent (no signal
applied) by connecting both bases to ground.
2. Measure DC values of Vc1, Vc2, VE, IB1, IB2 and IE.
3. Measure the differential gain (only one input used), from each input, and the
common-mode gain (both inputs connected to the same source) by applying
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1kHz sinusoidal input voltages as shown in table (1). For each input
condition (1st – diff. mode, 2nd diff. mode, 3rd common mode).
4. Sketch all waveforms (Vin1, Vin2, Vc1 and Vc2) for each input condition; be
sure to include DC levels, peak to peak voltages, and relative phase
information.
Input condition
Vin1
Vin2
Vc1
Vc2
Vpp ∟0
Vpp ∟0
Vpp ∟0
Vpp ∟0
1st – diff. mode
50 m
0m
…….
…….
2nd– diff. mode
0m
50 m
…….
…….
3rd -com. mode
50 m
50 m
…….
…….
Table (1)
5. Using the measured data in table (1) calculate Avcm, Avdm and CMRR
6. Simulate the circuit shown in figure (1) via PSpice ( DC & AC analysis).
Compare the gain found via measurement and justify any possible
differences ( Vin =50 mV, 1KHz).
Remark : for realistic simulation, you need to create a Pspise model for your
Q2N2222 BJTs. To this end, click the BJT in your PSpise schematic to select it,
and then click Edit, PSpise model, add the line (+ βf = 100) and then save and
close.
7. Fill in the table (1) by simulation results also.
Exercises :
1. Calculate the DC Q-points for the transistors shown in the circuit in figure (1).
Assume that βf = 100.
2. For this circuit, evaluate Avcm, Avdm and CMRR.
3. Comment on your result.
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Experiment 7 & 8
Operational Amplifier
‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬
Objective :
To study how to design and build a basic the Op-Amp used in inverting and noninverting amplifiers, inverting summing amplifier, integrator and differentiator.
Pre-lab :
1. Design an inverting amplifiers with gain -1 and -10 and input impedance of
least 1K. Use available resistor values.
2. Design non-inverting amplifiers with gain 1 and 10. Use available resistor
values.
-
For part 1 and 2 , plot the voltage gain as a function of the frequency in
the range 0 to 50 kHz ( simulation).
3. Design a summing amplifier to implement the function Vo= - (V1+2V2).
-
For part 3, generate the output voltage waveform if V1 as a sine wave or a
square wave of 2 volt peak and V2 is a DC voltage of 1 volt.
4. Design an integrator circuit so that when the input is a sine wave of
frequency 1 KHz, the output voltage has the same amplitude (unity gain ).
5. Design a differentiator circuit so that when the input is a sine of frequency 1
kHz, the output voltage has the same amplitude (unity gain).
-
For part 4 and 5, generate the output voltage waveform if the input is a
sine wave or a square wave of 2 volt peak and of frequency 500 Hz, 1kHz,
and 2 kHz.
Theoretical Background:
A basic model of an ideal operational amplifier is shown in figure (1). An op-amp is a
direct coupled device with differential inputs and a single ended output. The op-amp
responds only to the difference voltage between the two input terminals, not to their
common potential. A positive going signal at the inverting (-) input produces a
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negative going signal at the output, whereas the same signal at the non-inverting (+)
input produces a positive going output. With a differential input voltage, Vin, the
output voltage , Vo will be Avo Vin, where Avo is the open loop gain of the op-amp.
Both input terminals of the op-amp will always be used, regardless of the
application. The output is single ended and is referred to ground. Bipolar (±) power
supplies are most commonly used, which allows both positive and negative output
voltages.
Properties that are useful in describing the operation of operational amplifiers are
listed below and the ideal values given. Figure (1) illustrates the relationships
between the op-amp and these properties.
1. The voltage gain is high – Ideal value Avo is = ∞ .
2. The input resistance is high – Ideal value Rin = ∞ .
3. The output resistance is low – ideal value Ro = 0 .
4. The bandwidth is high – ideal value BW = ∞ .
5. The CMRR – ideal value = ∞ .
Figure (1) : Equivalent circuit of an operational amplifier
From these ideal characteristics, we can deduce two very important additional
properties of the operational amplifier. Since the voltage gain approaches infinite,
any output signal developed will be the result of an infinitely small input signal.
Thus, in essence:
1. The differential input voltage is zero.
2. There is no current flow into either the inverting or the non-inverting signal
input terminal because of the infinite input resistance.
These two axioms will be used repeatedly in the analysis and design of circuits using
op-amps. Once these properties are understood, the operation of virtually any circuit
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using an op-amp can be logically deduced. For the most real op-amps, these ideal
calculations are very close to the actual conditions.
Most linear op-amp circuits can be divided into two general classes; inverting and
non-inverting. Other circuits can be a combination of both. In the next two sections
we briefly review these two basic configurations.
1. Inverting configuration :
The basic inverting configuration is shown in figure (2). Because of the virtual
short and because the non-inverting terminal is grounded, we say that there is a
virtual ground at the inverting terminal. The final closed loop gain expression is :
The negative sign justifies the term " inverting" . In the more general case that
resistors are replaced by impedances.
Figure (2) : Basic inverting configuration
2. Non-inverting configuration :
The basic non-inverting configuration is shown in figure (3). The final closed loop
gain expression is :
Since the closed loop gain is positive, the term " non-inverting" is justified.
Vi
3
+
OUT
2
Vo
6
Rf
LM741
R1
0
Figure (3) : Basic non-inverting configuration
٤٣
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Voltage follower : a particularly simple version of the non-inverting circuit with
unity gain is the voltage follower shown at figure (4). The name "follower" is due
to the fact that the output voltage "follows" the input. Voltage followers are
widely used to provide buffering between high internal resistance sources and a
load.
Vi
3
+
2
Vo
6
OUT
LM741
Figure (4) : Voltage follower
3. Inverting summing amplifier :
By adding additional input resistors to the basic inverting circuit of figure (2). We
have the summing amplifier (inverting ) shown in figure (5) with three inputs.
The output voltage is given by
:
If R1 = R2 = R3 = R , then ;
V1
V2
V3
R1
Rf
R2
2
-
R3
Vo
OUT
3
0
6
+
LM741
Figure (5) : Inverting summing amplifier
4. Inverting integrator :
Referring to the general inverting circuit of figure (2), if Zf is a capacitor and Z1 is
a resistor, then we have the inverting integrator of figure (6). Assuming that the
capacitor has zero voltage at t = 0, the output voltage is given by :
٤٤
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
C
R
Vi
2
-
Vo
OUT
3
6
+
LM741
0
Figure (6) : Inverting integrator
Integrators suffer from DC components in the input voltage. If the input voltage
has a non-zero average value "DC term", then when this term is integrated it
becomes a linear ramp which over time will saturate the op-amp. Furthermore,
small DC voltages and currents present at and between the inputs of the op-amps
(known as input offset voltages and currents) also get integrated and they could
over time saturate the op-amp.
Integrators are widely used in practice because their frequency response has low
pass characteristics, which tends to attenuate noise that may be present in the
input voltage that noise has predominantly high frequency content.
5. Inverting differentiator :
By reversing the resistor and the capacitor in the integrator, we get the inverting
differentiator shown in figure (7). The output voltage is given by :
R
C
2
Vi
-
Vo
OUT
3
0
6
+
LM741
Figure (7) : Inverting differentiator
٤٥
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Lab Work :
Check the designs you have prepared in your pre-lab. Lab results should be included
in your report.
You will use lm741 op-amp in the lab. Figure (8) illustrates its pin diagram.
Figure (8) : Pin diagram of lm741 op-amp
Exercises:
Discuss and compare your lab results and simulation outputs.
٤٦
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Experiment 09
Power transistors
‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬
Objectives:
To learn about power amplifiers types and know the characteristics of each type.
Theoretical Background:
Amplifier classes represents the amount the output various over one cycle of
operation for a full cycle of input signal (return to section 12.1 in your book).
Amplifier efficiency is defined as the ratio between input power to output power.
Power Amplifier may be classify to:
Class A
Class B
Class AB
Class C
Class D
3. Class A
The power into amplifier is provided by supply. Without input signal the dc current
drawn is the collector bias ICQ . Then the input power drawn from supply is:
Pi(dc)=Vcc *ICQ
The output power (ac power) is given by :
Po(ac)= VCE (rms) *Ic(rms)
The efficiency is:
%η =
P
P
Po(ac)= I2c(rms)*Rc
o
(ac )
i
(dc )
×100%
The maximum efficiency is equal to 25%
V2
Vcc 22V
R1
Rc
R2
20k
0
V1
C1
10u
0
100
Q1
Q2N3904
0
٤٧
Po(ac)= V2CE (rms)/
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Figure (1) :series-fed Class A amplifier
4. Class B
Idc= 2*I(p)/pi
Pi(dc)= Vcc * Idc
P2Q= Pi(dc) - Po(ac)
PQ = 0.5* P2Q
Where
Po(ac)= V2L(rms)/RL
Idc is the dc current drawn from power supplies
PQ is the dissipated power by each transistor
The efficiency is: %η =
P
P
o
(ac )
i
(dc )
×100%
The maximum efficiency is equal to 78.5%
V1
R2
R4
R3
68
22V
1k
1
0
Q1
C1
100u
Q2N3904
D1
D1N4002
V3
Vi
RL
R1
C2
R6
Q4
1
8
100u
0
Q2N3905
R7
R5
68
0
V2
1
22V
0
٤٨
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Lab work :
1) Connect the circuit in figure 1.
2) Adjust the function generator to sinusoidal of amplitude 1 V at a frequency at 1
kHz.
3) Using wattmeter measure the input power .
4) Using wattmeter measure the output power on Rc .
5) Calculate the efficiency and verify less than maximum efficiency.
6) Connect the circuit in figure 2.
7) Adjust the function generator to sinusoidal of amplitude 1 V at a frequency at 1
kHz.
8) Using wattmeter measure the deliver power by the two power supply .
9) Using wattmeter measure the output power on RL.
10) Calculate the efficiency and verify less than maximum efficiency.
Exercises :
For figure1& figure2 :
1.
calculate the efficiency using equations (mathematically)
2.
Using ORCAD plot the output and determine VP_P and then calculate
the efficiency.
3.
compare between result that you get in exercise and compare with
result you get from practical experience.
٤٩
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
Experiment 10
SCR&TRIAC
‫ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ‬
Objectives:
•
To familiar with dimmer circuit and SCR.
Silicon controlled rectifier (SCRs)
There are many devices in the SCR (thyristor) family including the power thyristor,
the gate turn-off thyristor (GTO), the field controlled thyristor (FCT), the triac, etc.
A thyristor consists of a 4-layer silicon wafer with 3 P-N junctions. It has two power
terminals, called the anode (A) and cathode (K), and a third control terminal called
the gate (G).
Thyristor has two state Forward biased state if the anode voltage is larger than
cathode voltage, else Reverse biased state.
From the above curve When we apply forward bias voltage a small current flow,
this current called Forward leakage current. Until we reach Forward Breakdown
Voltage the resistance of thyristor will be small and current will flow from anode
to cathode.
٥٠
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
When we apply negative voltage reverse leakage current will flow. Until reverse
breakdown voltage thyristor will damage.
Methods of triggering a thyristor:
•
High forward voltage
•
High rate of rise of forward voltage, dV/dt.
•
Excessive temperature.
•
Positive current gate pulse: This is the normal way that a thyristor is brought
into conduction. The gate pulse must be of a suitable amplitude and duration,
depending on the size of the thyristor.(We are interested in this method)
It can be turned off only by reducing the anode current below holding current
(current which thyristor turn off when reach it).
TRIAC
The Triac is a member of the thyristor family. But unlike a thyristor which conducts
only in one direction (from anode to cathode) a triac can conduct in both directions.
Thus a triac is similar to two back to back (anti parallel) connected thyristosr but
with only three terminals. As in the case of a thyristor, the conduction of a triac is
initiated by injecting a current pulse into the gate terminal. The gate looses control
over conduction once the triac is turned on. The triac turns off only when the current
through the main terminals become zero.
Lab work :
1) Connect the circuits in the previous figures.
2) Using oscilloscope view the result.
3) Change the value of resistor R4 in and not the change record your result in
the below table.
٥١
ENG. AMANI ABU REYALA
Electronics II
Lab Manual
ENG.DEEB ASAD TUBAIL
4) Replace the SCR by triac
X1
R4
11600
2N1595
V1
C2
1n
R3
1k
0
R4
1K
2K
3K
4K
5K
6K
8K
10K
11.5K
Exercise :
Delay angle=w*t
V average
The photo
1) Repeat the lab work steps using orcad simulation program.
٥٢
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