LAB MANUAL
ANALOGE ELECTRONIC CIRCUITS
Department of
Electronics and Communication
Engineering
Silicon Institute of Technology
Bhubaneswar
Analoge Electronics Lab Manual 2
Dept.of ECE
ANALOG ELECTRONICS CIRCUIT LAB
List of Experiments
1. Design and simulate BJT bias circuit and compare the results.
2. Design and simulate JFET/MOSFET bias circuit and compare the results.
3. Design and simulate BJT common-emitter circuit and compare D.C and
A.C performance.
4. Design and simulate JFET/MOSFET common-emitter circuit and
compare D.C and A.C performance.
5. Design and simulate the frequency response of a common-emitter
amplifier: low frequency, high frequency and mid frequency response.
6. Design & simulate Darlington connection and current mirror circuits.
7. Study the operation of Power amplifiers.
8. Application of Op-Amp as differentiator, integrator, square wave
generator.
9. Obtain the band width of FET/ BJT using Square wave testing of an
amplifier.
10. R.C phase shift oscillator/Wien-Bridge Oscillator using OPAmp /Crystal
Oscillator
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AIM OF THE EXPERIMENT :
To Design and simulate BJT bias circuit and compare the
results.
OBJECTIVE:
To Finding out the resistance value simulate the BJT bias circuit
in Multisim .
PRELAB:
1.Study the operation and working principle BJT Voltage
divider biasing.
2.Identify all the formulae you will need in this Lab.
3.Study the procedure of using Multisim tool (Schematic &
Circuit File).
SOFTWARE TOOL:
•Multisim
THEORY
Transistor Biasing
The proper flow of zero signals collector current and the
maintenance of proper collector emitter voltage during the
passage of signal is known as transistor biasing.
The basic purpose of transistor biasing is to keep the base
emitter junction forward bias & collector base junction
properly reverse bias during is known as biasing circuit.
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Biasing is very essential for the proper operation of transistor
in any circuit. For a faithful amplification transistor biasing is
required. Most important biasing method is voltage divider
bias method.
Voltage divider bias method
It is widely used method for providing biasing stabilization
to transistor, In this method two resistances RA and RB are
connected across the supply voltage VCC and providing
biasing. Since the current IB is in microampere, so we can
neglect it. Which implies the resistors RA and RB are in
series. Hence the voltage VCC is divided between RA and RB.
CIRCUIT DIADR AM:
CALCULATIONS
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Given Data
Transistor (BD115), Calculate
β =?
VCE =10 Volt, IC = 2 mA, RC = 5 KΩ,
Assume, I1 = 10IB, VCC = 25 Volt, VBE = 0.7 Volt
Calculate RA, RB, RE = ?
For RE
VCC - VCE = IC ( R C + R E )
For RB
VB = VBE + IE R E = VBE + IC R E
IC
,I =10 IB = I2 (Assumption)
 1
V
RB = B
I1
IB =
For RA
I1 =
VCC
(R A + RB )
PROCEDURE:
▪ Open Multisim Software to design .
▪ Select on New editor window and place the required
component on the circuit window.
▪ Make the connections using wire and set Multimeter.
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▪ Check the connections and the specification of components
value properly.
▪ Go for simulation using Run Key observe the output .
OBSERVATION
Parameters
VCE(Volts)
IC(mA)
Theoretical Values
(Calculation
Values)
Practical Values
(Taken Values)
% Error =
Experimental - Theoritical
CONCLUSION:
Theoritical
×100
0
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REVIEW QUESTIONS:
• What is transistor biasing?
Transistor Biasing is the process of setting a transistors DC
operating voltage or current conditions to the correct level so
that any AC input signal can be amplified correctly by
thetransistor.
• What is Q-point?
The operating point of a device, also known as bias point,
quiescent point, or Q-point, is the steady-state voltage or current
at a specified terminal of an active device (a transistor or
vacuum tube) with no input signal applied.
• What is stability factor?
Stability Factor (S) is defined as the change in the collector
current of a Bipolar Junction Transistor (BJT) with respect to
change in various transistor parameters like as Collector
Leakage Current.
• What is thermal runaway condition?
Thermal runaway refers to a situation where an increase in
temperature changes the conditions in a way that causes a
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further increase in temperature, often leading to a destructive
result. It is a kind of uncontrolled positive feedback.
• What are the commonly used biasing circuits?
The following discussion treats five common biasing circuits
used with class-A bipolar transistor amplifiers:
I.
II.
Fixed bias
Collector-to-base bias
III.
Fixed bias with emitter resistor
IV.
Voltage divider bias or potential divider
V.
Emitter bias
• What is β-independent bias circuit?
The operating point (or quiescent point, q-point, bias point, etc.)
Of a bipolar transistor (BJT) circuit, the circuit design can
affected by the bias point due to the value of beta (current gain)
of the transistor.
• Fixed bias circuit is not popularly used. Why?
Fixed bias is rarely used in linear circuits, ie. Those circuits
which use the transistor as a current source. Instead it is often
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used in circuits where transistor is used as a switch. However,
one application of 'fixed' bias is to achieve crude automatic gain
control in the transistor by feeding the base resistor from a dc
signal derived from the ac output of a later stage.
• What is a load line?
A load line is used in graphical analysis of non linear electronic
circuits, representing the constraint other parts of the circuit
place on anon linear device, like adiode or transistor.
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AIM OF THE EXPERIMENT:
To Design and simulate JFET biasing circuit and compare the
results.
OBJECTIVE:
To Finding out the resistance value simulate the JFET bias
circuit in Multisim .
PRELAB:
1.Study the operation and working principle JFET self biasing.
2.Identify all the formulae you will need in this Lab.
3.Study the procedure of using Multisim tool (Schematic &
Circuit File).
SOFTWARE TOOL:
•Multisim
THEORY
The Field Effect Transistor, or simply FET however, uses the
voltage that is applied to their input terminal, called the Gate to
control the current flowing through them resulting in the output
current being proportional to the input voltage. As their
operation relies on an electric field (hence the name field effect)
generated by the inputGate voltage, this then makes the Field
Effect Transistor a “VOLTAGE” operated device.
Mathematical Analysis
As gate source junction is reverse biased, So IG = 0 A and,
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therefore VG = IGRG = 0 V, hence ID = IS
Voltage at source is
VS = IS R S = IDR S
Applying
KVL at Input loop
-I R - V - I R = 0
G
G
GS
S
S
VGS = -IDR S
So, voltage drop across RS provides the biasing Voltage VGG and
no external source is requiredfor biasing and this is the reason
that it is called Self biasing.
The operating point can easily be determined from equation
V = V - I (R + R )
DS
DD
D
D
S
Self biasing of a JFET stabilizes its quiescent operating point
against any change in its parameters like transconductance.
CIRCUIT DIADR AM:
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CALCULATIONS
• VDD = 12 Volts
• ID = 2.5 mA
• RG = 1MΩ
• Assume RD = 3 RS
• VDS = 7.4 Volts
• Calculate RD, RS, VGS =?
V = V - I (R + R )
• Find RS = ?
DS
• Find RD = ?
DD
D
D
RD = 3 R S
VGS = -IDR S
S
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• Find VGS = ?
PROCEDURE:
▪ Open Multisim Software to design .
▪ Select on New editor window and place the required
component on the circuit window.
▪ Make the connections using wire and set Multimeter.
▪ Check the connections and the specification of components
value properly.
▪ Go for simulation using Run Key observe the output .
OBSERVATION
Parameters
VDS(Volts)
ID(mA)
Theoretical Values
(Calculation
Values)
Practical Values
(Taken Values)
% Error =
Experimental - Theoritical
Theoritical
×100
0
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CONCLUSION:
REVIEW QUESTIONS:
AIM OF THE EXPERIMENT:
To Design and simulate BJT CE Amplifier.
OBJECTIVE:
To Finding out the resistance value, voltage gain, input & output
impedance for bypass and unbypass emitter resister.
PRELAB:
1.Study the operation and working principle BJT biasing & Re
model.
2.Identify all the formulae you will need in this Lab.
3.Study the procedure of using Multisim tool (Schematic &
Circuit File).
SOFTWARE TOOL:
•Multisim
THEORY
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➢ Anything that amplifies, or makes something larger or
more intense.
➢ An appliance or circuit that increases the strength of a
weak electrical signal without changing the other
characteristics of the signal.
➢ An amplifier is an electronic device that increases the
voltage, current, or power of a signal. BJT is one of the
electronics device which is used as an amplifier.
➢ Condition for BJT amplifier?
➢ Before amplification BJT should biased properly to get Qpoint in constant current region. The signal should applied
at Q-point to get faithful amplification.
➢ Benefits of Voltage divider biasing
➢ Only one dc supply is necessary.
➢ Operating point is almost independent of β variation.
➢ Operating point is stabilized against shift in temperature.
➢ V(B) is made quite stable.
➢ Therefore Voltage divider CE configuration is the most
commonly used circuit for transistor amplifiers.
DC Analysis
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Capacitor blocks DC hence, treated as open ckt.
VCC - VCE = IC ( R C + R E )
For RB
VB = VBE + IE R E = VBE + IC R E
IC
,I =10 IB = I2 (Assumption)
 1
V
RB = B
I1
IB =
For RA
I1 =
VCC
(R A + RB )
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AC Analysis
The capacitors allow AC signal but blocks DC signal, hence for
this analysis Capacitors are treated as short circuit.
Furthermore, consider DC voltage source to short circuit and
DC current source to open circuit. Transistor replaced by re
model.
Cc and Cb are called coupling capacitor
Ce is called by pass capacitor
Considering Bypass capacitor Ce
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Considering Bypass capacitor Ce
Calculate
re =
26mV 26mV
=
IE
IC
Input Impedance Zi = RB//RA// βre
Output Impedance Z0 = Rc
Voltage gain AV?
AV =
Vo -Ib R c -R c
=
=
Vi
Ibre
re
Considering Unbypass capacitor Ce
Input Impedance Zi = RB//RA// β(re +RE)
Voltage gain AV
AV =
Vo
-R c
-R
=
= c
Vi  ( re + R E ) R E
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Measurement or Practical value
For Bypass and Unbypass
Input Impedance Zi
Zi =
Vin
Iin
Iin =
Vs - Vin
Rs
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Output Impedance Zo ?
1. Measure output voltage without connecting RL i.e. Vo
2. Connect RL and measure the voltage across RL i.e VL
3. Vary the pot till VL=Vo/2 (Maxm power transmission)
4. At VL=Vo/2, Disconnect the pot and Measure the resistance
of the pot by using Millimeter in resistance mode i.e.
Zo=RC
AV =Vo/Vin
PROCEDURE:
▪ Open Multisim Software to design .
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▪ Select on New editor window and place the required
component on the circuit window.
▪ Make the connections using wire and set Multimeter &
probe.
▪ Check the connections and the specification of components
value properly.
▪ Go for simulation using Run Key observe the output .
For input impedance:
• Measure the voltage Vin & Vs by using voltage probe
• Compare it with theoretically input impedance
For output impedance
• Measure output voltage without connecting RL, i.e Vo
• Connect RL and measure the voltage across RL i.e VL
• Vary the potentiometer till VL= V0/2,
• At VL = Vo/2, Disconnect it and measure the resistance of
the pot by using Multimeter i.e. ZO = RC
UNBYPASS
Repeat all the steps by removing the capacitor ‘Ce’.
Observation
OBSERVATION
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Parameters
VDS(Volts)
ID(mA)
Theoretical Values
(Calculation
Values)
Practical Values
(Taken Values)
Table-2 (BYPASS)
Parameters
Theoretical
Values
ZIN(KΩ)
ZO(KΩ)
AV
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Practical
Values
% Error
Table-3 (UN BYPASS)
Parameters
ZIN(KΩ) ZO(KΩ)
Theoretical
Values
Practical
Values
% Error
CONCLUSION:
REVIEW QUESTIONS:
AV
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AIM OF THE EXPERIMENT:
To Design and simulate JFET CS Amplifier.
OBJECTIVE:
To Finding out the resistance value, voltage gain, input & output
impedance for bypass emitter resister.
PRELAB:
1.Study the operation and working principle JFET biasing.
2.Identify all the formulae you will need in this Lab.
3.Study the procedure of using Multisim tool (Schematic &
Circuit File).
SOFTWARE TOOL:
•Multisim
THEORY
Junction Field Effect Transistor (JFET)
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FET CS Amplifier Circuit
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As gate source junction is reverse biased, So IG = 0 A,
Unlike a bipolar transistor circuit, the junction FET takes
virtually no input gate current allowing the gate to be treated as
an open circuit.
DC ANALYSIS
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• VDD = 12 Volts
• ID = 2.5 mA
• RG = 1MΩ
• Assume RD = 3 RS
• VDS = 7.4 Volts
• Calculate RD, RS, VGS =?
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Calculation
Find RS = ?
Find RD = ?
RD = 3 R S
Find VGS = ?
AC Analysis
The capacitors allow AC signal but blocks DC signal, hence for
this analysis
Capacitors are treated as short circuit. Furthermore, consider DC
voltage source
to short circuit and DC current source to open circuit. FET is
replaced by ac
model.
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Considering Bypass capacitor CS
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Considering Bypass capacitor CS
✓ Calculateg
m
=
ID
VGS
✓ Input Impedance = Zi = RG
✓ Output Impedance Zo ?
Z0 = RD//rd = RD (since rd is about 40 to 50 KΩ or rd =10
RD)
✓ Voltage gain AV?
Vo = −g m Vgs (rd //R D )
✓
 Av =
Vo
= −g m (rd //R D )  −g m R D
Vi
PROCEDURE:
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▪ Open Multisim Software to design .
▪ Select on New editor window and place the required
component on the circuit window.
▪ Make the connections using wire and set Multimeter &
probe.
▪ Check the connections and the specification of components
value properly.
▪ Go for simulation using Run Key observe the output .
Measurement or Practical value
For Bypass and Unbypass
Input Impedance Zi
Zi =
Vin
Iin
Iin =
Vs - Vin
Rs
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AV =Vo/Vin
For input impedance:
• Measure the voltage Vin & Vs by using voltage probe
• Compare it with theoretically input impedance
For output impedance
• Measure output voltage without connecting RL, i.e Vo
• Connect RL and measure the voltage across RL i.e VL
• Vary the potentiometer till VL= V0/2,
• At VL = Vo/2, Disconnect it and measure the resistance of
the pot by using Multimeter
For Voltage gain
• AV =Vo/Vin
OBSERVATION
Parameters
Theoretical Values
(Calculation
Values)
VDS(Volts)
ID(mA)
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Practical Values
(Taken Values)
Table-2 (BYPASS)
Parameters
Theoretical
Values
Practical
Values
% Error
CONCLUSION:
ZIN(KΩ)
ZO(KΩ)
AV
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AIM OF THE EXPERIMENT:
To Design and simulate the frequency response of a commonemitter amplifier: low frequency, high frequency and mid
frequency response.
OBJECTIVE:
Finding out the Frequency response curve at different frequency
(Low, High & Medium frequency).
PRELAB:
1.Study the operation and working principle frequency response
of CE amplifier.
2.Identify all the formulae you will need in this Lab.
3.Study the procedure of using Multisim tool (Schematic &
Circuit File).
SOFTWARE TOOL:
•Multisim
THEORY
Frequency Response of Amplifiers
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➢ The output voltage leads the input voltage due to the
presence of the capacitance having reactance. fc=1/2πRC
➢ This is practically open circuit at a very low frequency and
short circuit at a very high frequency.
➢ If the frequency of the network is shown in fig. varied, the
output voltage will change because of the reactance of the
capacitor. Voltage gain verses frequency shown in fig. is
called frequency response of the lead network.
➢ The cut-off frequency is the frequency at which XC is equal
to R i.e. fc=1/2πRC.
➢ The cut-off frequency is the frequency at which XC is equal
to R i.e. fc=1/2πRC. This is also called Half power
frequency or -3dB(decibell) cut off frequency.
Mid band voltage gain (Avmid)
➢ The voltage gain in the mid band of a lead network with
source and load resistance is the gain in the range of
frequencies at which the capacitor acts approximately like
an a.c. short
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➢
Low Frequency Response
High Frequency Response
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This actually indicates that the response of the device below the
mid-band region frequency (i.e. where the voltage gain is 1) is
termed low frequency response and the response of the device
above the mid-band region frequency is termed high frequency
response.
Generally, the frequency response analysis of a circuit or system
is shown by plotting its gain, that is the size of its output signal
to its input signal, Output/Input against a frequency scale over
which the circuit or system is expected to operate.
Then by knowing the circuits gain, (or loss) at each frequency
point helps us to understand how well (or badly) the circuit can
distinguish between signals of different frequencies.
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BJT CE amplifier
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For the RC coupled amplifier, the drop at low frequencies is due
to the increasing reactance of Cc or Ce, while its upper limit is
determined by either can the parasitic capacitive element of the
network and frequency dependent of the gain of the active
device.
Given Data:
VCC = 12volts
CB = CC = 10 µF CE = 47µF
RS=10 K RA=33 RB = 10K RC =2.2K RE =1K
a. Software REquired – multisim
b. Resistors
c. Capacitors- CB =CC = 10µF , CE = 47µF
d. Semiconductor – BC107
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PROCEDURE:
▪ Open Multisim Software to design .
▪ Select on New editor window and place the required
component on the circuit window.
▪ Make the connections using wire and set Multimeter &
probe.
▪ Check the connections and the specification of components
value properly.
▪ Go for simulation using Run Key observe the output .
Observation
Seria Frequenc O/P
l No y
voltag
e
(Hz)
(VO)
Voltag AV/AVmi Gain in db =
e Gain d
20log(AV/AVmi
d)
(Av) =
Vo/Vin
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CONCLUSION:
REVIEW QUESTIONS:
1. What is the equation for voltage gain?
Ans:
2. What is cut off frequency? What is lower 3dB and upper
3dB cut off frequency?
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Ans: In electronics, cutoff frequency or corner frequency is the
frequency either above or below which the power output of a
circuit, such as a line, amplifier, or electronic filter has fallen to a
given proportion of the power in the pass band. Most frequently
this proportion is one half the pass band power, also referred to as
the 3 dB point since a fall of 3 dB corresponds approximately to
half power. As a voltage ratio this is a fall to of the pass band
voltage
3. What are the applications of CE amplifier?
Ans: Low frequency voltage amplifier, radio frequency circuits
and low-noise amplifiers
4. What is active region?
Ans: The active region of a transistor is when the transistor has
sufficient base current to turn the transistor on and for a larger
current to flow from emitter to collector. This is the region where
the transistor is on and fully operating. In this region JE in forward
bias and JC in reverse bias and transistor works as an amplifier
5. What is Bandwidth of an amplifier?
Ans: Bandwidth is the difference between the upper and lower
frequencies in a continuous set of frequencies. It is typically
measured in hertz, and may sometimes refer to passband
bandwidth, sometimes to baseband bandwidth, depending on
context. Passband bandwidth is the difference between the upper
and lower cutoff frequencies of, for example, a bandpass filter, a
communication channel, or a signal spectrum. In case of a lowpass filter or baseband signal, the bandwidth is equal to its upper
cutoff frequency.
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AIM OF THE EXPERIMENT:
To Study of Darlington connection and current mirror circuits.
OBJECTIVE:
Finding out the current and voltage gain of darlingtone
connection and comparion of currents in current mirror circuits.
PRELAB:
1.Study the operation and working principle of darlingtone pair
and current mirror circuit.
2.Identify all the formulae you will need in this Lab.
3.Study the procedure of using Multisim tool
(Schematic & Circuit File).
SOFTWARE TOOL:
•Multisim
THEORY
Darlington pair
➢ A Darlington pair is two transistors that act as a single
transistor but with a much higher current gain. This mean
that a tiny amount of current from a sensor, microcontroller or similar can be used to drive a larger load. The
Darlington Pair can be made from two transistors as shown
in the diagram or Darlington Pair transistors are available
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where the two transistors are contained within the same
package.
current gain
➢ Transistors have a characteristic called current gain. This is
referred to as its hFE. The amount of current that can pass
through the load in the circuit above when the transistor is
turned on is:
➢ Load current = {input current x transistor gain (hFE)}
➢ The current gain varies for different transistors and can be
looked up in the data sheet for the device. For a normal
transistor this would typically be about 100. This would
mean that the current available to drive the load would be
100 times larger than the input to the transistor.
➢ Darlington Pair uses
➢ In some applications the amount of input current available
to switch on a transistor is very low. This may mean that a
single transistor may not be able to pass sufficient current
required by the load.
➢ As stated earlier this equals the input current x the gain of
the transistor (hFE). If it is not possible to increase the
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input current then the gain of the transistor will need to be
increased. This can be achieved by using a Darlington Pair.
➢ A Darlington Pair acts as one transistor but with a current
gain that equals:
Total current gain (hFE total) = current gain of transistor 1
(hFE t1) x current gain of transistor 2 (hFE t2)
So for example if you had two transistors with a current
gain (hFE) = 100:
(hFE total) = 100 x 100
(hFE total) = 10,000
➢ You can see that this gives a vastly increased current gain
when compared to a single transistor. Therefore this will
allow a very low input current to switch a much bigger load
current.
➢ Analysis of Darlington Pair
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β1 = β2=110 VCE = 5 Volt,
IC = 2 mA, VCC = 27 Volt, VBE = 1.5 Volt,
R1=470K R2=220K, RC=1.2K, RE=680 Ω, RIN=10K
C1=C2=10µF C3=47µF
Measurement or Practical value
✓ Input Impedance Zi ?
Zi =
Vin
Iin
Iin =
Vs - Vin
Rs
✓ Current Gain β ?
β =I out /I in
✓ Voltage Gain Av ?
Av =Vout /Vin
OBSERVATION
Current Gain of Darlington Pair, β =.........
Individual β of transistor = β’=.........
Input impedance of emitter follower =.........Ω
Voltage gain of Darlington pair =...........V
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Current Mirror Circuit
➢ A current mirror is a circuit block which functions to
produce a copy of the current in one active device by
replicating the current in second active device.
➢ An important feature of the current mirror is a relatively
high output resistance which helps to keep the output
current constant regardless of load conditions.
➢ Another feature of the current mirror is a relatively low
input resistance which helps to keep the input current
constant regardless of drive conditions.
➢ The current being 'copied' can be, and often is, a varying
signal current. Conceptually, an ideal current mirror is
simply an ideal current amplifier with a gain of -1.
➢ The current mirror is often used to provide bias currents
and active loads in amplifier stages.
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Given Data→
VCC = 12 Volt, VBE = 0.7 Volt,R1=1.1K
Calculate Iref=? Iref = (VCC-VBE)/R1
OBSERVATION
Parameter
Iref
I
Theoritical
Practical
PROCEDURE:
▪ Open Multisim Software to design .
▪ Select on New editor window and place the required
component on the circuit window.
0
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▪ Make the connections using wire and set Multimeter &
probe.
▪ Check the connections and the specification of components
value properly.
▪ Go for simulation using Run Key observe the output.
CONCLUSION:
REVIEW QUESTIONS:
AIM OF THE EXPERIMENT:
Study the operation of Power amplifiers.
.OBJECTIVE:
Design of class A, B & AB power amplifiers
PRELAB:
1. Study the operation and working principle of power
amplifiers.
2. Identify all the formulae you will need in this Lab.
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THEORY
The power amplifier works on the basic principle of converting
the DC power drawn from the power supply into an AC voltage
signal delivered to the load.
Although the amplification is high the efficiency of the
conversion from the DC power supply input to the AC voltage
signal output is usually poor.
The main feature of a power amplifier or large power amplifier is
the circuit power efficiencies, Maximum amount of power that
the circuit is capable of handling and the impedance matching to
the output device.
Various Types Or Class Of Amplifier:
• Class A Amplifier – has low efficiency of less than 40% but
good signal reproduction and linearity.
• Class B Amplifier – is twice as efficient as class A amplifiers
with a maximum theoretical efficiency of about 70% because the
amplifying device only conducts (and uses power) for half of the
input signal.
• Class AB Amplifier – has an efficiency rating between that of
Class A and Class B but poorer signal reproduction than class A
amplifiers.
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• Class C Amplifier – is the most inefficient amplifier class as
only a very small portion of the input signal is amplified therefore
the output signal bears very little resemblance to the input signal.
Class C amplifiers have the worst signal reproduction.
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HARDWARE REQUIRED:a.Equipments – CRO,FG
b. Resistors –
R1 , R4, R6 =1K, R5 =10 K, R7= 4.7K
R3= 10 K POT , R2= 4.7 K POT
c. CapacitorsC1 = C2 =10µF
d. Semiconductor –
BC 107
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PROCEDURE: • Collect all the required equipments from the laboratory.
• Connect the transistor,capacitors and the resistors as per the
circuit diagram on the Breadboard.
• Before connecting the source voltage, Switch ON the kit
and adjust the VCC at 12volt through Multimeter from 0 to
30 volt variable voltage source with respect to ground point
of the trainer kit.
• Before measurement check all the circuit connection and
verify it through concerned faculty.
• By varying the potentiometer (Pot-1 & Pot-2) Different
mode of operation can be occurred.
• Trace the output waveforms for different amplifiers and
compare with the input signal.
CONCLUSION:
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AIM OF THE EXPERIMENT:
To Study Application of Op-Amp.
OBJECTIVE:
Study of the different application of op-amp.
PRELAB:
1.Study the operation and working principle of differentiator,
integrator and schimtt trigger circuit.
2.Identify all the formulae you will need in this Lab.
THEORY
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➢ An Operational Amplifier (Op-Amp) is an integrated
circuit that uses external voltage to amplify the input
through a very high gain. We recognize an Op-Amp as a
mass-produced component found in countless electronics.
What an Op-Amp looks like to a lay-person
What an Op-Amp looks like to an engineer
Op-Amp Differentiator
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R = 1k
C=0.1µF
Op-Amp Integrator
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R = 1k
C=0.1µF
Schmitt trigger
Schmitt trigger is an electronic circuit with positive
feedback which holds the output level till the input signal to
comparator is higher than the threshold. It converts a
sinusoidal or any analog signal to digital signal.
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To obtain this threshold voltage we use voltage divider
circuit R1-R2where voltage through R1 is feedback to the
(+VE) I/P.
The voltage across R1 is reference voltage which depends
on the value and polarity of VO when VO = +Vsat, the
voltage across R1 is Vut. The input voltage Vin must be
slightly more +ve than Vut in order to cause the o/p VO to
switch from +Vsat to – Vsat.
When Vin < Vut, VO is +Vsat
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So, Vut, = R1 (+Vsat)/(R1 + R2)
On the order hand when VO = - Vsat the voltage across R1 is
refere to as Vit Vin must be slightly more –Ve then Vit is
order to switch VO from –Vsat to +Vsat
Vit = R1 (-Vsat)/(R1 + R2).
➢ Vut = 20mv, Vlt = -20mv,
➢ R1 = 100 ohm +Vsat =12 v
➢ Vut = R1 (+Vsat)/(R1 + R2)
R2 = ?
Hardware Required
a. Equipments – CRO,FG .
b. Resistors –R1 , R2
c. Capacitors- NIL
d. Semiconductor – OP-AMP IC 741
e. Miscellaneous – Bread board and wires
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PROCEDURE: • Collect all the required equipments from the laboratory.
• Connect the IC and the resistors as per the circuit diagram
on the Breadboard.
• Before connecting the source voltage, Switch ON the kit
and adjust the VCC at 12volt through Multimeter from 0 to
30 volt variable voltage source with respect to ground point
of the trainer kit.
• Before measurement check all the circuit connection and
verify it through concerned faculty.
CONCLUSION:
REVIEW QUESTIONS:
1. Explain what is an operational amplifair?
An operational amplifier, abbreviatred as op-amp, is
basically a multi-stage, very high gain, direct-coupled,
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negative feedback amplifier that uses voltage shunt
feedback to provide a stabilized voltage gain.
2. Define offset voltage as applied to an op-amp?
Input offset voltage may be defined as that voltage which
is to be applied between the input terminals to balance the
amplifier.
3. Define slew rate?
Slew rate of an op-amp is defined as the maximum rate of
change of output voltage per unite time and is expresses in
V/µs.
4. Explain what kind of negative feedback is present in a non
inverting op-amp?
Negative voltage-series feedback.
5. Explain what is an inverting amplifier?
In an inverting amplifier, the input is connected to the
minus or inverting terminal of op-amp.
6. Explain what is a differential amplifier?
Differential amplifier is a combination of inverting and non
inverting amplifier the voltage difference between input
lines neither of which is grouned.
7. Explain what is an integrator?
An integrator is a circuit that performs a mathematical
operation called integration.
8. Explain what are the applications of integrators?
Integrators are widely used in ramp or sweep generators,
filters, analog computers etc.
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9. Op-amp is used mostly as an integrator than a
differentiator. Explain why?
Op-amp is used mostly as an integrator than a differentiator
at high frequency, gain is high and so high-frequency noise
is also amplified which absolutely abstract the
differentiated signal.
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AIM OF THE EXPERIMENT:
To Study Square wave testing of an Amplifier.
OBJECTIVE:
Find out the different parameters, such as rise time and width,
high cutoff frequency, low cutoff frequency and %age of tilt.
PRELAB:
1. Study the operation and working principle of amplifier.
2. Identify all the formulae you will need in this Lab.
THEORY
➢ Wave is a type of signal which contains amplitude, phase
and frequency.
➢ An amplifier is being tested at high or low frequencies for
the shape of the output wave form (frequency response)
whether it is properly amplified or not.
➢ The high-frequency response measures essentially the
ability of the amplifier to respond faithfully to rapid
variation of the signal.
➢ The low-frequency response measures the fidelity
(accuracy, exactness, precision, faithfulness, authenticity)
of the amplifier for slowly varying signal.
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➢ The use of square wave testing is significantly less time
consuming than applying a series of sinusoidal signals at
different frequencies and magnitude to test the frequency
response of the amplifier.
➢ The use of square wave testing is significantly less time
consuming than applying a series of sinusoidal signals at
different frequencies and magnitude to test the frequency
response of the amplifier.
➢ A Square wave is a type of signal which contains a series of
sinusoidal terms of different frequencies and magnitude as
per Fourier series expansion.

1
1

sin2fs t
+
sin2(3fs )t
+
sin2(5fs )t


 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯→ 3 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯→ 5 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯→

Third harmonic term
Fifth harmonic term
4  Fundamental term

v = Vm

1
1
  1
sin2(7fs )t
+
sin2(9fs )t
+ ..... +
sin2(nfs )t
+

n ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯→ 
 7 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯→ 9 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯→
Seventh harmonic term
N int h harmonic term
nth harmonic term 

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The actual high cutoff frequency (or BW) can be determined
from the output waveform by carefully measuring the rise time
defined between 10% and 90% of the peak value, as shown in
the Fig.
tr=90% of Vmax time – 10% of Vmax time
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Substituting into the following equation will provide the upper
cutoff frequency, and since BW = f2- f1 ≈ f2, the equation also
provides an indication of the BW of the amplifier
The low cutoff frequency can be determined from the output
response by carefully measuring the tilt and substituting into one
of the following equations:
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The low cutoff frequency is then determined from
GIVEN DATA:
Transistor- BC107
VCC = 12volts, CB = CC = 10 µF
CE = 47µF , RS=10 K
RA=33K, RB = 10K ,RC =2.2K, RE =1K
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Hardware Required
a. Equipments – CRO & FG
b. Resistors –RC , RS ,
RA , RB ,RE
c. Capacitors- CB =CC = 10µF , CE = 47µF
d. Semiconductor – BC107
e. Miscellaneous – Bread board and wires
PROCEDURE
• Collect all the required equipments from the laboratory.
• Connect the transistor and the resistors as per the circuit
diagram on the Breadboard.
• Before connecting the source voltage, Switch ON the kit
and adjust the VCC at 12volt through Multimeter from 0 to
30 volt variable voltage source with respect to ground point
of the trainer kit.
• Before measurement check all the circuit connection and
verify it through concerned faculty.
OBSERVATION
0
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tr
FH =
0.35/tr
Vmax
CONCLUSION:
REVIEW QUESTIONS:
Vmin
tilt
% of tilt
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AIM OF THE EXPERIMENT:
To Study RC Phase Shift Oscillator .
OBJECTIVE:
Design of RC phase shift oscillator using OP-Amp.
PRELAB:
1. Study the operation and working principle of RC phase shift
oscillator .
2. Identify all the formulae you will need in this Lab.
THEORY
➢ RC phase shift oscillator is a sinusoidal oscillator used to
produce sustained well shaped sine wave oscillations.
➢ It is used for different applications such as local oscillator
for synchronous receivers, musical instruments, study
purposes etc.
➢ The main part of an RC phase shift oscillator is an op amp
inverting amplifier with its output feed back into its input
using a regenerative feedback RC filter network, hence the
name RC phase shift oscillator.
➢ The use of square wave testing is significantly less time
consuming than applying a series of sinusoidal signals at
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different frequencies and magnitude to test the frequency
response of the amplifier.
➢ By varying the capacitor, the frequency of oscillations can
be varied.
➢ The feedback RC network has a phase shift of 60 degrees
each, hence total phase shift provided by the three RC
network is 180 degrees.
➢ The op amp is connected as inverting amplifier hence the
total phase shift around the loop will be 360 degrees. This
condition is essential for sustained oscillations.
Use Of RC Stages
Number of RC stages help improve the frequency stability. The
total phase shift introduced by the feedback network is 180
degrees, if we are using N RC stages each RC section provide
180/N degree phase shift.
When 2 RC sections are cascaded, the frequency stability is low.
For 3 sections cascaded the phase change rate is high so there is
improved frequency stability.
However for 4 RC sections there is an good phase change rate
resulting in the most stable oscillator configuration. But 4 RC
sections increases cost and makes circuit complexity.
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Hence phase shift oscillators make use of 3 RC sections in
which each section provides a phase shift of 60 degree. The
latter is generally used in high precision applications where cost
is not much regarded and only accuracy plays a major role.
Frequency of oscillation (F)
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Hardware Required
a. Equipments – CRO
b. Resistors –R1 , R2 , R3 =100 ohm, R4 = 10 K POT
c. Capacitors- C1 = C2 = C3 = 0.1 µF
d. Semiconductor – OP-AMP IC- 741
e. Miscellaneous – Bread board and wires
PROCEDURE:
• Collect all the required equipments from the laboratory.
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• Connect the ic ,capacitors and the resistors as per the circuit
diagram on the Breadboard.
• Before connecting the source voltage, Switch ON the kit
and adjust the VCC at 12volt through Multimeter from 0 to
30 volt variable voltage source with respect to ground point
of the trainer kit.
• Before measurement check all the circuit connection and
verify it through concerned faculty.
Vary the potentiometer 10k to get proper oscillation and
compare it with the calculated frequency.
Trace the wave from at each test point i.e., at the output of
op-Amp at each RC stage with help of CRO.
Observation
PARAMETERS
Theoritical
Practical
Error
CONCLUSION:
FREQUENCY
0
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REVIEW QUESTIONS: