Download List of Experiments 1. V-I characteristics of PN Junction Diode in

NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
List of Experiments
1. V-I characteristics of PN Junction Diode in Forward bias.
2. V-I characteristics Zener Diode in Reverse Bias.
3. To determine the frequency response of transistor in CE mode.
4. To determine the frequency response of transistor in CB mode.
5. To draw the frequency response of RC coupled amplifier.
6. To draw V-I characteristics of U.J.T.
7. Inverting and Non Inverting Amp using Op-Amp.
8. Summing and Subtractor Amp using Op-Amp.
9. Integrator Amp using Op-Amp.
10. Differentiator Amp using Op-Amp.
11. A stable multi-vibrator using 555 timer IC
Department of Electronics and Communication
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Experiment No.1
To plot the characteristics curve of PN junction diode in Forward & Reverse bias
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
Department of Electronics and Communication
CS-302 Lab Manual
Page 1 of 4
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
PN Junction Diode
Object: To plot the characteristics curve of PN junction diode in Forward & Reverse bias.
Apparatus Required:
S.No. Apparatus
1.
Bread Board
2.
Voltmeter
3.
Ammeter
4.
DC power supply
5.
Connection Wire
Specification
6*2 inch
0-10 volt D.C.
0-100 mA.
0-10 Volt
single wire
Required No.
01
01
01
01
08-10
CIRCUIT DIAGRAM:-
sREVERSE BIAS & FORWARD BIAS:
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NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
The Basic Diode Symbol and Static V-I Characteristics.
Theory: - This is a two terminal device consisting of a P-N junction formed either in Ge or Si
crystal. A P-N junction is illustrated in fig. shows P-type and N-type semiconductor pieces
before they are joined.
P-type material has a high concentration of holes and N-type material has a high concentration of
free electrons and hence there is a tendency of holes to diffuse over to N side and electrons to Pside. The process is known as diffusion.
Volt-Ampere Characteristics Of P-N Junction: - Fig.shows the circuit arrangement for
drawing the volt-ampere characteristics of a P-N junction diode. When no external voltage is
applied the circuit current is zero. The characteristics are studied under the following two heads:
(i) Forward bias
(ii) Reverse bias
(i)Forward bias:- For the forward bias of a P-N junction, P-type is connected to the positive
terminal while the N-type is connected to the negative terminal of a battery. The potential at P-N
junction can be varied with the help of potential divider. At some forward voltage (0.3 V for Ge
and 0.7V for Si) the potential barrier is altogether eliminated and current starts flowing. This
voltage is known as threshold voltage(Vth) or cut in voltage or knee voltage .It is practically
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CS-302 Lab Manual
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NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
same as barrier voltage VB. For V<Vth, the current flow is negligible. As the forward applied
voltage increases beyond threshold voltage, the forward current rises exponentially.
(ii)Reverse bias: - For the reverse bias of p-n junction, P-type is connected to the negative
terminal while N-type is connected to the positive terminal of a battery.
Under normal reverse voltage, a very little reverse current flows through a P-N junction. But
when the reverse voltage is increased, a point is reached when the junction break down with
sudden rise in reverse current. The critical value of the voltage is known as break down (VBR).
The break down voltage is defined as the reverse voltage at which P-N junction breakdown
with sudden rise in reverse current.
Observation Table
Forward BiasS.No.
Forward voltage Vf (volt)
Forward Current If( mA)
Forward voltage Vf (volt)
Forward Current If( μA)
Reverse BiasS.No
Result:
The V-I characteristics of junction diode in forward and reverse bias condition has been be
plotted on the graph
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CS-302 Lab Manual
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NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: ECE Dept.
Experiment No.2
To plot the V-I characteristics of a zener diode in reverse wise.
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
Page 1 of 7
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: ECE Dept.
Zener Diode
Objective: - To plot the characteristics of a zener diode.
Appratus:- Training kit, connecting wires, multimeter.
Theory: -
Special diodes are constructed which can operate at voltage that equal or exceed their
breakdown voltage rating. These special diode are commonly referred to as zener diode. The
overall forward and reverse characteristics of the zener diode are similar to those of an
ordinary junction diode. The primary difference is simple that the zener diode is specifically
designed to operate with a reverse bias voltage that is high enough to
Cause the device to breakdown and conduct a high reverse current. Then the reverse current
through the diode increases at an extremely rapid rate as the reverse voltage increases beyond
the breakdown point.
The V-I curve therefore shows that beyond the breakdown point, a very large change in
reverse current is accompanied by only a very small change in reverse voltage. This action
occurs because the resistance of the diode drops considerably as its reverse voltage is increased
beyond the breakpoint. Once the breakdown point is exceeded the diode is said to be operating
in its zener breakdown region or simply its zener region.
Page 2 of 7
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: ECE Dept.
VOLTAGE REGULATION WITH ZENER DIODE:Although the zener diode may be used to perform a number of important functions it is
perhaps most widely used in applications where it is continually reverse biased so that it
operates constantly within its zener breakdown region. Under these conditions, the zener
diode so effectively used to provide voltage stabilization or regulation.
Procedure: -
1. Construct the circuit as shown in fig. using take 1K ohm potentiometer on your
1. Experimenter, a 470 ohm resistor and the zener diode. Figure shows one-way you can
write the circuit.
2. Power supply voltage (approx.15 V.D.C.) will be applied to the 1K ohm potentiometer
(designated as R1) to control the voltage applied to the zener diode (D1) and its series
470 ohm resistor (R2). Observe the polarity of the voltage applied to D1. Is D1 forward
or reverse biased?
3. Turn the 1K potentiometer R fully counter clockwise, and then turn on your
experimenter.
4. Connect voltmeter across D1 as indicated in fig. then turn R1 slowly clockwise and
observe the increase in voltage across D1 as indicated on your meter. Continue turning
R1 until the voltage across D1 stops increasing at a rapid rate and effectively remains
constant. At this point stop turning D1 and as accurately as you can measure the voltage
acrossD1. Record this voltage in the DIODE VOLTAGE column (upper space).
5. Next use voltmeter to measure the voltage across R2. Then use the voltage across R2
and the resistance of R2 (470 ohms) to calculate the current flowing in the circuit
according to ohms law (I=E/R). Your calculated value of current represent the amount of
Page 3 of 7
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: ECE Dept.
current that is now flowing through resister R2 and diode D1. Record this current in the
diode current column (upper space).
6. Measure the input voltage Vin between potentiometer terminal 1 and 2 indicated in fig.
Record your value in the INPUT VOLTAGE column (upper space) of the table. Now you
will make several voltage measurements, which must be performed quickly to avoid
overheating the diode. First measure the voltage across D1 as you turn potentiometer
D1 fully clockwise. Note the voltage across D1 with R1 fully clockwise and record this
voltage in the DIODE VILTAGE column (lower space).Next measure the input voltage and
record this value in fig. Then measure the voltage across R2. The voltage across R2 is
now equal to ------- volts. Now turn off your experiment.
7. Use the voltage across R2 (recorded above) and the resistance of R2 to calculate the
current flowing through R2 according to ohms law. This calculated value of current
represents the current that flows through R2 and D1. Record this current in the DIODE
CURRENT column (lower space).
8. Reverse the diode leads and turn R1 fully counterclockwise. Then turn on the
experimenter. Connect your voltmeter between terminal 1 and 2 of potentiometer R1
and adjust the input voltage Vine to 5 volts.
9. Measure the voltage across the diode with your voltmeter. The diode voltage now equal
to ---------- volts. Is the diode forward or reverse biased?
10. You will now use your experimental circuit to supply a regulated output voltage of 5.1
volts to various resistive loads. When a load resistor is connected across the sneer
diode, the circuit effectively becomes a simple voltage regulator circuit. This circuit is
capable of operating wit input voltage between 9 and 12 volts and output load currents
between 0 and 30 milliamperes. You will now test this circuit by setting the input
voltage to its lower limit of 9 volts and observing the regulated output voltage for
various load currents. Reverse the diode leads to return the circuit to its original
condition.
11. Insure that the +ve voltage control is turned fully clockwise. Then turn on your
experimenter. Next connect your voltmeter between the arm of the potentiometer and
the anode D1 (across R2 and D1) and adjust the 1K ohms potentiometer R1 until the
meter indicates that the voltage applied to R1 and D1 is equal to 9 volts.
12. With no load resistor connected across diode D1 (no load current) use your voltmeter to
measure the voltage across D1. Record the indicated voltage in the OUTPUT VOLTAGE
column of the table.
13. Now connect a 1K ohm resistor across diode D1. This resistor will serve as a load and will
draw a load current of approximately 5 mill amperes at the rated output voltage of 5.1
volts. Measure the output voltage across D1 at this time and record the indicated
voltage in the appropriate space in the OUTPUT VOLTAGE column.
14. Now repeat step 14 using load resistor with values of 470,220 and 47 ohm. These
resistors will draw load currents of approximately 11, 23 and 108 mill amperes
respectively. Assuming the output voltage remains at 5.1 volts. After you connect each
load resistor across D1 and measure the voltage across D1, record the indicated voltage.
Page 4 of 7
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: ECE Dept.
Then turn off your experimenter and explain any unusual variations in output voltage
noted.
Observation Table:INPUT VOLTAGE
OUTPUT VOLTAGE
OUTPUT CURRENT
Results: -
The V-I characteristics of zener diode has been studied and graph is plotted.
Precautions:1. Patch cords should be properly connected.
2. Power supply should be on after completed the connections.
Lab Quiz :Q.1 Zener breakdown results basically due to
(A) impact ionisation
(B) strong electric field across the junction
(C) emission of electrons
(D) rise in temperature
Q.2 Zener diode works in
(A) Forward bias
(B) Reverse bias
(C) Both a and b
(D) none of these
Q.3 A Zener diode is based on the principle of:
(A) Thermionic emmision
(B) Tunneling of charge carriers across the junction
Page 5 of 7
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: ECE Dept.
(C) Diffusion of charge carriers across the junction
(D) None of these
Q.4 Silicon is not suitable for fabrication of light-emitting diodes because it is:
(A) An indirect band gap semiconductor
(C) A wide band gap semiconductor
(B) A direct band gap semiconductor
(D) A wide band gap semiconductor
Q.5 A Zener diode:
(A) Has a high forward voltage rating
(B) Has a sharp breakdown at low reverse voltage
(C) Is useful as an amplifier
(D) None of the above
Q.6 Which of these is a best description of a Zener diode?
(A) It operates in the reverse region
(B) It is a constant voltage device
(C) It is a constant current device (D) None of the above
Q.7 The LED is usually made of materials like:
(A) GaAs
(B) C and Si
(C) GeAs
(D) None of the above
Q.8 Zener diodes are used as:
(A) Reference voltage elements
(B) Reference current elements
(C) Reference resistance
(D) None of the above
Q.9 Zener diodes are:
(A) Specially doped p–n junctions
(B) Normally doped p–n junctions
(C) Lightly doped p–n junctions
(D) None of the above
Q.10 A general propose diode is more likely to suffer an avalanche breakdown rather than a Zener
Page 6 of 7
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: ECE Dept.
breakdown because:
(A) It is lightly doped
(B) It is heavily doped
(C) It has weak covalent bonds (D) None of the above
Further reading resources:
Book: Lab experiment related theory available in following books:
Book Name
Author
1. Electronics devices and circuits theory
Boylestad
2. Integrated electronics
Millman
3.Electronic Devices and Circuits, PHI
Graham Bell
4. Microelectronics, Oxford Press.
Sendra and Smith
5. Electronic Circuits Analysis and Design
Donald A Neamen
Web resources:
1. coefs2.njit.edu
2. eecs.oregonstate.edu/education/docs/ece111/CompleteManual.pdf
3. forum.jntuworld.com
4. www.vidyarthiplus.com
5. www.svcetedu.org
Page 7 of 7
Page No.
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Experiment No.3
Transistor Characteristics
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Transistor Characteristics
Object: To plot the Transistor input and output characteristics in Common Emitter Mode.
Appratus:- Training kit, connecting wires, multimeter.
Theory: Circuit Configurations: A transistor has three terminals hence when it is connected in
a circuit one of its terminals in common to input and output parts of the circuits. Three circuits
configurations in which a transistor can be connected are discussed below (discussion has been
limited to NPN transistor).
1.
Common Emitter Configuration :- When a transistor is used in common emitter
configuration the input is fed between its base and emitter terminal and output is taken between
the collector and emitter terminal as shown in fig.3.1 shows the circuit for determining the input
and output characteristics of NPN transistor in common emitter configuration. Figure 2.1 Show
the wiring diagram for practically determining the common emitter characteristics using this
training board.
Figure 3.1 wiring diagram of common emitter configuration
Input Characteristics:
For input characteristics, the collector voltage i.e. Vc is kept constant. The base voltage is
varied in small steps and corresponding values of base current are observed. The readings are
plotted on a graph sheet with the base voltage Vb on the X-axis and the base current Ib on the Yaxis. Fig shows the practical curves obtained for
various transistors.
From the practical curves obtained, it is
observed that the curve does not start from zero
base voltage (Vb). Appreciable base current
flows when the base voltages are 0.3 volts for
germanium transistor and 0.6 volts for silicon
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
transistor. From the curve we can obtain the input resistance of the transistor.
Input Resistance Rin = Vb/Ib, at certain Vc value
Common Emitter:
Procedure: - Input Characteristics:
1.
Using suitable patch cords make connections as per shown in fig. For NPN transistor.
2.
Keep the knobs of both 0 – 10 V DC supplies to fully anticlockwise position.
3.
Switch on the power to the training board.
4.
Set the collector voltage to a certain value say 1 V.
5.
Vary the base voltage VB in 15 mV (20 mV) steps and observe the corresponding base
current by keeping the current meter in 200 A ranges.
6.
Take the observations as per table 1 and plot the readings on a graph sheet. Take VB on
the X-axis and IB on the Y-axis.
Table – 3.1
S.No.
VC =.......... Volt
VB
IB
VC =........... Volt
VB
IB
1.
2.
3.
4.
5.
Output Characteristics:
For obtaining the output characteristics, the base current is kept fixed at a certain value.
The collector voltage is increased in certain steps and corresponding readings of collector current
are noted. The reading can be repeated for
another value of base current. The graph of Vc
Vs. Ic is plotted for each fixed value of Ib. fig
shows the practical curves obtained for various
transistors. From the curves it is observed that:
No collector current flows when Ib=0
For a certain fixed value of base current the
collector current does not vary, much with the
change of collector voltage.
The output resistance of a transistor can be obtained as:
R0 = Vc/Ic, at certain value of Ib.
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Also the current gain B of the transistor can be calculated as:
B = Ic/Ib, for a certain value of Vc.
Procedure: - Output Characteristics:
1.
Using suitable batch cords make connections as per shown in fig. For NPN transistor.
2.
Keep the knobs of both 0 – 10 V DC supplies to fully anticlockwise position.
3.
Switch on the power to the training board.
4.
Set the base current to a certain value say 25 A with the help of 0 – 10 V DC supply of
the input circuit.
5.
Now vary the collector voltage from 0 – 10 V in steps say 1 V and note down the
corresponding values of the collector current IC as per table 2.
6.
Repeat the collector voltage and collector current for different settings of the base
current.
7.
Plot the of collector voltage along X-axis and collector current along Y-axis.
Table – 3.2
S.No.
IB =........... A
VC
IC
IB =........... A
VC
IC
1.
2.
3.
4.
5.
Result: Input and Output characteristics of a Transistor in Common Emitter Configuration are
studied.
The h-parameters for a transistor in CB configuration are:
a. The Input resistance (hib)
__________________ Ohms.
b. The Reverse Voltage Transfer Ratio (hrb) __________________.
c. The Output Admittance (hob)
__________________ Mhos.
d. The Forward Current gain (hfb)
__________________.
Precautions:
1. While performing the experiment do not exceed the ratings of the transistor. This may
lead to damage the transistor.
2. Connect voltmeter and ammeter in correct polarities as shown in the circuit diagram.
3. Do not switch ON the power supply unless you have checked the circuit connections as
per the circuit diagram.
4. Make sure while selecting the emitter, base and collector terminals of the transistor.
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Experiment No.4
Transistor Characteristics
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Transistor Characteristics
Object: To study and plot the Transistor input and output characteristics in Common Base Mode.
Appratus:- Training kit, connecting wires, multimeter.
Theory: Circuit Configurations: A transistor has three terminals hence when it is connected in a circuit
one of its terminals in common to input and output parts of the circuits. Three circuits configurations in
which a transistor can be connected are discussed below (discussion has been limited to NPN transistor):
Common Base Configuration:
The Common Base (CB) (Figure 2.1) circuit characteristics constitute a family of static
characteristics plots of collector current versus collector-base voltage for several values of emitter current.
Here the input is given between base and emitter and output is taken between collector and base as shows
in fig . Shows circuit diagram and fig.2.1 shows the wiring diagram for practically determining the
characteristics in the common base configuration.
Input Characteristics:
VEE (Volts)
Observation Table 2.1
Input Characteristics
VCB = 0V
VCB = 4V
VEB (Volts)
IE (mA)
VEB (Volts)
IE (mA)
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
For input characteristics in the common base
configuration the collector Vc is kept constant at
a certain value. The emitter voltage Ve is varied
and corresponding value of emitter current Ie are
observed. Fig. shows the practical curves
obtained for various transistors. From these
curves we observe the following:
1.
The curves start from zero.
2.
The emitter current increases sharply at an emitter voltage which is about 0.2V for a Ge and about
0.6V for a Si transistor can be obtained as follows:
Ri = Ve/Ie, for a certain of Vc.
Procedure:- Input Characteristics
1. Connect the circuit as shown in the circuit diagram.
2. Keep output voltage VCB = 0V by varying VCC.
3. Varying VEE gradually, note down emitter current IE and emitter-base voltage(VEE).
4. Step size is not fixed because of nonlinear curve. Initially vary VEE in steps of 0.1 V.
Once the current starts increasing vary VEE in steps of 1V up to 12V.
5. Repeat above procedure (step 3) for VCB = 4V.
Output Characteristics:
Observation Table 2.2
Output Characteristics
VCC (Volts)
IE = 0mA
IE = 5 mA
IE = 10mA
VCB (Volts) IC (mA) VCB (Volts) IC (mA) VCB (Volts) IC (mA)
For the output characteristics of a transistor in common base configuration, the emitter current Ie
is kept constant at a certain value. The collector
variations corresponding to variations of the
collector voltages are observed. Fig shows the
practical curves for various transistors. From the
curves, we observe as follows:
1.
2.
3.
The curves start from a point 0 instead of
zero.
This point is about 0.2V for a Ge.
Transistor and about 0.6V in case of a Si
transistor.
Point 0 is of polarity to the usual polarity of
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
4.
collector voltage.
This point 0 is nearly same for all values of emitter current.
This output resistance of a transistor in common base configuration can be determined as follows:
R0 =Vc/Ic, for a certain of Ie.
The current gain can also be calculated as:
α = Ic/Ie, for a certain value of Vc.
Procedure: - Output Characteristics
1. Connect the circuit as shown in the circuit diagram.
2. Keep emitter current IE = 5mA by varying VEE.
3. Varying VCC gradually in steps of 1V up to 12V and note down collector current IC and
collector-base voltage (VCB).
4. Repeat above procedure (step 3) for IE = 10mA.
Repeat above procedure (step 3) for IE = 10mA.
Result:
Input and Output characteristics of a Transistor in Common Base Configuration are studied.
The h-parameters for a transistor in CB configuration are:
a. The Input resistance (hib)
__________________ Ohms.
b. The Reverse Voltage Transfer Ratio (hrb) __________________.
c. The Output Admittance (hob)
__________________ Mhos.
d. The Forward Current gain (hfb)
__________________.
Precautions:
1. While performing the experiment do not exceed the ratings of the transistor. This may
lead to damage the transistor.
2. Connect voltmeter and ammeter in correct polarities as shown in the circuit diagram.
3. Do not switch ON the power supply unless you have checked the circuit connections as
per the circuit diagram.
4. Make sure while selecting the emitter, base and collector terminals of the transistor.
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Experiment No. -5
To draw the frequency response of RC coupled amplifier.
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
Department of Electronics and Communication
CS-302 Lab Manual
Page 1 of 3
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Object :To draw the frequency response of RC coupled amplifier.
Apparatus Required:
S.No.
1.
2.
3.
4.
5.
Name of Instruments/Kit
RC Coupled Amplifier Trainer kit
Cathode Ray Oscilloscope
Function Generator
BNC Cable
Patch Chords
Specifications
ETB-45
30 MHz
30 MHz
75 Ω
Banana Pin
Quantity
01
01
01
03
05
Theory:
(a)
Frequency Response: The voltage gain of amplifier base varies with frequency the
curve between voltage gain and signal frequency of an amplifier is known as
frequency response. The gain of the amplifier increases from 0 till it became
maximum at Fr called resonance frequency is the frequency increases beyond fr the
gain decreased.
(b)
Bandwidth : The range of the frequency over with the gain is equal to or greater
than 70.7% of the maximum gain is known as bandwidth from the figure it is clear
that f1 – f2 is bandwidth f1 is the lower cutoff frequency and f2 is the higher cutoff
frequency. The frequency f1 and f2 is also called 3DB frequency or half power
frequency.
R – C Coupled Amplifier:
It is the most popular type of coupling dives use for the voltage amplification in figure it
is seems that a coupling capacitor Cc is used to connect the output of the first stage to the input
of the second stage. Resistance R1, R2 and RE used for the biasing and stability.
When an AC signal i9s apply to the bias of the first transistor it amplify across the load
RC this amplified signal is fade to the bias of the second stage through CC in this way we get the
overall signal increase at the output of the second stage.
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Page 2 of 3
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Frequency Response of RC Coupled Amplifier:
(i)
At the lower frequency (<50 Hz) the reactance of CC is very high hence very small
part of the signal will pass from one stage to another stage.
(ii)
At high frequency (>20 kHz) the reactance of CC is very small and it behave the short
circuit thus because of the loading effect reduce the voltage gain.
(iii)
At mid frequency (50 to 20 KHz) the voltage gain of amplifier is constant the effect
of the CC in this frequency range is such as to mention uniforms voltage gain.
Procedure :
(1)
Take the frequency response of the individual stage.
(2)
Measure the output of the first stage at point A.
(3)
Measure the output of the second stage at point B.
(4)
Draw the frequency response of the R – C coupled amplifier.
Observation Table :
S.No.
Fin (Hz)
Vin (Volts)
Vout (Volts)
Gain (dB) = 20 log10 (Vout/Vin)
Result:-
Department of Electronics and Communication
CS-302 Lab Manual
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NAME OF LABORATORY: : ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE:CS-302
NAME OF DEPARTMENT: ECE Dept.
Experiment No. -6
To plot the V-I characteristics of a given U.J.T.
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
Page 1 of 7
NAME OF LABORATORY: : ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE:CS-302
NAME OF DEPARTMENT: ECE Dept.
Uni Junction Transistor
Objective: - To plot the V-I characteristics of a given U.J.T.
Appratus:- Trainer kit (volt meter,current meter,variable P/S,U.J.T.), Patch cords, Multimeter,
C.R.O.
Theory: - A Uni-junction transistor (U.J.T.) or double base diode is arranged as shown in the fig.
It serves as a trigger generator for S.C.R. gating circuit, as such, it has advantages of stable firing
voltage, low firing current, and sufficient current output to trigger the rectifier.
Construction is on a thin slab of silicon with two base contract B1 and B2. Alloyed to the slab is a
P-Emitter electrode and junction. Base B2 is made (+)ve with respect to B1 by voltage EBB, and
a fraction of this voltage appears between the emitter E and B1, the bar action as a voltage
divider. If the applied emitter potential EE is less than EBB then P is negative with respect to N
and the diode is reversed biased. Only reverse saturation current is present and operation is in
region A of fig.
If EE is made greater than n EBB the diode is foreard biased with a large emitter current and a
low forward voltage drop exists between E and B1.The holes introduced from the P region
make the E to B1 region positive, and electrons are attracted there .As a result of the greatly
increased in the numbers of charge carriers, the resistance falls the current through B1 rises
and the oltage falls, gi ing a the negati e resistan e hara teristi s in region B of fig.
Turn-on occurs when EE is equal EP the peak point voltage, which is given as approximately EP=
n EBB + 0.7V.
Where 0.7 volt is as approximation of the usual diode voltage drop. The parameter n is called
the intrinsi stand of ratio and lies et een 0. 7 and o.7 depending on UJT hara teristi s.
The negative resistance region ends when the voltage reaches the normal diode volt-ampere
curve to zero. Before turn on the device acts simply as a voltage divider and
RB1
n= --------------RB1+RB2
Page 2 of 7
NAME OF LABORATORY: : ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE:CS-302
NAME OF DEPARTMENT: ECE Dept.
The resistance of the silicon between the basis will approach several thousand ohms with the
resistance RB1 and RB2 measured between each base and the emitter.
The UJT with its negative resistance action makes a fast switch for gating the SCR. In the circuit
capacitor C1 charges through R1 until EE reaches the peak point voltage EP, when the UJT
triggers and discharges C1 through RB1. When EE reaches a low value perhaps, the capacitor
can no longer supply the necessary emitter base current and the UJT turn off. The period of
oscillation is given by
1
T= R1 C1 In ------------- Sec.
1- n
Base resistor RB1 provides an output voltage pulse during the very short high current transition
through the negative resistance region as shown in fig.
Resistance RB1 should be low enough to prevent the D.C. voltage due to inter base current from
exceeding the minimum gating voltage for the SCR..The resistor R1 has its maximum value set
by the requirement . The lower limit on R1 should place its load line in the region of max . The
frequency of oscillation can be controlled through adjustment of R1. The amplitude of the
output pulse is reduced by an increase in UJT temperature, but an increase in temperature
results in a smaller required gating pulse for an SCR. Therefore the two temperature effects are
compensatory.
Procedure: -
1.
2.
3.
4.
5.
Make connection as shown in fig.
Fix the value EBB at 0 volt and very EE.
Note down the current and voltage.
Plot the V-I characteristics as shown in fig.
Repeat the above procedure by keeping voltage EBB at 5v,10v,15v,20v.
Page 3 of 7
NAME OF LABORATORY: : ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE:CS-302
NAME OF DEPARTMENT: ECE Dept.
Page 4 of 7
NAME OF LABORATORY: : ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE:CS-302
NAME OF DEPARTMENT: ECE Dept.
Observation Table:EBB= 0V
EE (V)
IE (mA)
EE (V)
IE (mA)
2. EBB= 5V
RESULT:Precautions:1. Patch cords should be properly connected.
Page 5 of 7
NAME OF LABORATORY: : ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE:CS-302
NAME OF DEPARTMENT: ECE Dept.
2. Power supply should be on after completed the connections.
Suggestions:Lab Quiz :Q.1 UJT is a
(A) Unipolar
(B) Bipolar
(C) both
(D) None of these
Q.2 UJT is a
(A) current controlled device
(B) voltage controlled device
(C) both
(D) none of these
Q.3 When applied input voltage varies the resistance of a channel, the result is called:
(A) saturization
(B) polarization
(C) cutoff
(D) field effect
Q.4 UJT stands for ……………………………..
Q.5 FET is a
(A) Unipolar
(B) Bipolar
(C) Tripolar
(D) None of these
Q.6 In the constant-current region, how will the IDS change in an n-channel JFET?
(A) As VGS decreases ID decreases.
(B) As VGS increases ID increases.
(C) As VGS decreases ID remains constant.
(D) As VGS increases ID remains constant.
Q.7 A MOSFET has how many terminals?
(A) 2 or 3
(B) 2
(C) 3
(D) 3 OR 4
Further reading resources:
Book: Lab experiment related theory available in following books:
Page 6 of 7
NAME OF LABORATORY: : ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE:CS-302
NAME OF DEPARTMENT: ECE Dept.
Book Name
1. Electronics devices and circuits theory
2. Integrated electronics
3.Electronic Devices and Circuits, PHI
4. Microelectronics, Oxford Press.
5. Electronic Circuits Analysis and Design
Author
Boylestad
Millman
Graham Bell
Sendra and Smith
Donald A Neamen
Web resources:
1. coefs2.njit.edu
2. eecs.oregonstate.edu/education/docs/ece111/CompleteManual.pdf
3. forum.jntuworld.com
4. www.vidyarthiplus.com
5. www.svcetedu.org
Page 7 of 7
Page No.
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
EXPERIMENT NO:-7
To study operational amplifier
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
Department of Electronics and Communication
CS-304 Lab Manual
Page 1 of 5
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
OBJECT:
To study operational amplifier in following modes.
(1) Inverting amplifier
(2) Non-inverting amplifier
Apparatus Required:
S.No.
1.
2.
3.
4.
5.
Name of Instruments/Kit
Operational Amplifier Trainer kit
Dual Trace Cathode Ray Oscilloscope
Function Generator
BNC Cable
Patch Chords
Specifications
OAD-14
30 MHz
30 MHz
75 Ω
Banana Pin
Quantity
01
01
01
03
08
THEORY:
THE INVERTING AMPLIFIER:
Figure 1
Fig:(1) illustrates the first basic OP-AMP configuration the inverting amplifier. In this circuit, the
(+) input is grounded and the signal is applied to the input through Rin, with feedback returned
from the output through Rf.By applying the ideal OP-AMP properties, the distinguishing features
of this circuit may be analysis as follows :
Since the amplifier has infinite gain, it will develop its output voltages Eo with zero input
voltages, since the deferential input to A is Es, Es=0. If Es is zero, than the full voltage, in must
appear Rin making the circuit in Rin.
Iin = Ein / Rin
Also, since Is = 0 due to infinite impedance, the input current, Iin must also flow in Rf. The
output voltage, Eo appears across Rf and is negative due to a sign inversion.
Department of Electronics and Communication
CS-304 Lab Manual
Page 2 of 5
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Amplifier starting If in the terms of Eo and Rf than,
If = Eo / Rf
Since Iin and If are equal, we may state
Ein / Rin = -Eo / Rf
This equality may be restated in terms of gain as
Eo / Ein = Rf / Rin = Avo
Which is, in fact, the characteristics gain equation for the ideal inverting amplifier.
The gain of inverting amplifier can be verified by adjusting either Rf or Rin. If Rf is varied from
zero to infinity, the gain will also vary from zero to infinity since it is directly proportional to Rf.
The input impedance is equal to Rin and Ein and Rin alone determine Iin. Thus If =Iin for any
value of Rf.
The input of the amplifier or the junction of the input and feedback signals is a node of zero
voltage regardless of the magnitude of Iin. Thus the junction is a virtual ground a point that will
always be at the same potential as the (+) input. Since the input and output signals sum at this
junction, it is also known as summing point. This final characteristic leads to a third basic OPAMP which applies to closed loop operation. With the loop closed, the (-) input will be driven to
the potential of the (+) or reference input.
THE NON-INVERTING AMPLIFIER
Figure 2
Department of Electronics and Communication
CS-304 Lab Manual
Page 3 of 5
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
The second basic configuration of the ideal OP-AMP is the non-inverting amplifier, shown in
fig:2, in this circuit voltage Ein is applied to the (+) Rin voltage divider. Since on input current
flows into either input terminal, and since Es = 0, the voltage Ein is equal to E.
Hence by the thevenin's theorem
Rin / (Rin+Rf) * Eo = Ein
EoRin = (Rin+Rf)
Eo / Ein = (Rin+Rf) / Rin
Eo / Ein = 1+(Rf / Rin)
Which are the characteristics gains for the ideal non-inverting amplifier? Additional
characteristics of this configuration can also be deducted. The lower limit of gain occurs when Rf
= 0, which yields a gain of unity. In the inverting amplifier, the current Iin always determines If,
which is independent of Rf. Thus Rf may be used as a liner gain control capable of increasing
gain from a minimum of unity to a maximum of infinity. The input impedance is infinite, since an
ideal amplifier is assumed.
PROCEDURE:
INVERTING AMPLIFIER:
Ratio of the feedback resistance to the input resistance governs the gain of the amplifier.
Gain = -Rf / Rin = 10K ohms/1k ohms = -10
Department of Electronics and Communication
CS-304 Lab Manual
Page 4 of 5
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
Make the circuit connection as shown in fig.05 with the help of patch cords. Apply 1-volt dc and
note that output will be -10 times of the input voltage. Output of the Op-Amp cannot go beyond
-15 volts. So do not feed input more than +1.5V, when the input goes beyond ±1.5V.When the
input goes beyond ±1.5V, Op-Amp will go into saturation state.
Note that output will be inverted. Hence this circuit is called amplifier.
NON-INVERTING AMPLIFIER:
In a non-inverting amplifier input is amplified to non-inverting input terminal and gain can be
adjusted by changing feedback resistance. Here this circuit is designed for 10 gains. Since
component tolerance is ±1.5%, the result will be within ±1.5%. Make the circuit connections as
shown in fig.06 with the help of patch cords. Apply input (it should be less than 1.5V) and
observe the output. Output will be non-inverted and amplified by approximately 10 times.
OBSERVATION TABLE:
INVERTING AMPLIFIER:
S.no
Vin
Vout
Gain A=Vout / Vin
Vout
Gain A=Vout / Vin
1.
2.
3.
4.
5.
NON-INVERTING AMPLIFIER:
S.no
Vin
1.
2.
3.
4.
5.
RESULT:
Department of Electronics and Communication
CS-304 Lab Manual
Page 5 of 5
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
EXPERIMENT NO.-8
Summing Amplifier and Subtractor Amplifier
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
Department of Electronics and Communication
CS-304 Lab Manual
Page 1 of 4
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
OBJECT: - Design the amplifier in following modes using 741-IC.
1. Summing Amplifier Circuit
2. Subtractor Amplifier Circuit
Apparatus Required:
S.No.
1.
2.
3.
4.
5.
Name of Instruments/Kit
Operational Amplifier Trainer kit
Dual Trace Cathode Ray Oscilloscope
Function Generator
BNC Cable
Patch Chords
Specifications
OAD-14
30 MHz
30 MHz
75 Ω
Banana Pin
Quantity
01
01
01
03
08
THEORY:
SUMMING AMPLIFIER
Figure 1
Fig.2 shows the inverting configurations with three input Va, Vb & Vc. Depending on the
relationship between the feedback Rf &the input resistors Ra,Rb &Rc the circuit functions can be
verified by examining the expression for output voltage V0, which is obtained from kircoff's
current equation written at node V2.
Ia + Ib + Ic = If +Ib
Since R1 & a of the op-amp are ideally infinity, Ib =0anp & V1 = V2 = 0volts
Therefore
Va/Ra +Vb/Rb +Vc/Rc = -Vo/Rf
Department of Electronics and Communication
CS-304 Lab Manual
Page 2 of 4
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
V0 = -Rf(Va/Ra+Vb/Rb+Vc/Rc)
SUBTRACTOR AMPLIFIER
Figure 2
A basic differential amplifier can be used as a subtract or as shown in fig.3 in this fig. input signal
can be sealed to the desired values for the external resistor, when this is don the circuit is
referred to as scaling amplifier. In fig.3 external resistors are equal in value so the gain of the
amplifier is equal to 1.
For this fig. the O/P voltage of the differential amplifier with a gain of 10 is
Vo = -Rf/R(Va-Vb)
i.e
Vo = 10(Va-Vb)
Thus the output voltage Vo is equal to the voltage Vb applied to the non-inverting terminal,
hence the circuit is called a subtract or.
PROCEDURE
SUMMING AMPLIFIER
Make circuit connection as shown in fig 2. The O/P will be the 10 times of the sum of the input.
Don’t give input that the op-amp goes in saturation.
SUBTRACTOR AMPLIFIER
Make circuit connection as shown in fig.3 give two different I/P and measure the O/P. It will be
the 10 times of the difference of the inputs.
Department of Electronics and Communication
CS-304 Lab Manual
Page 3 of 4
NAME OF LABORATORY: ELECTRONIC DEVICE & CIRCUIT
LAB SUBJECT CODE: CS-302
NAME OF DEPARTMENT: - ECE
OVBSERVATION TABLE
SUMMING AMPLIFIER
S.No
Va
Vb
Vc
Vo(observed)
Vo(calculated)
Vc
Vo(observed)
Vo(calculated)
1.
2.
3.
4.
5.
SUBTRACTING AMPLIFIER
S.No
Va
Vb
1.
2.
3.
4.
5.
RESULT:-
Department of Electronics and Communication
CS-304 Lab Manual
Page 4 of 4
NAME OF LABORATORY:
LAB SUBJECT CODE:
NAME OF DEPARTMENT:
EDC Lab
CS-302
Electronics and Comm.
EXPERIMENT NO. – 9
Operational Amplifier as Integrator
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
NAME OF LABORATORY:
LAB SUBJECT CODE:
NAME OF DEPARTMENT:
EDC Lab
CS-302
Electronics and Comm.
OBJECTIVE: To the study of operational amplifier as integrator circuit.
APPARATUS REQUIRED:
S.No. Name of Instruments/Kit
Specifications
Quantity
1.
Operational Amplifier Trainer kit
OAD-14
01
2.
Dual Trace Cathode Ray
Oscilloscope
30 MHz
01
3.
Function Generator
30 MHz
01
4.
BNC Cable
75 Ω
03
5.
Patch Chords
Banana Pin
08
THEORY
The integrator
An integrator is shown in Fig. as input voltage, Ein is applied to Rin, thus developing
current Iin. As in the basic inverter, Es= 0, Is = 0, and If = Iin. The feedback element
in the integrator is a capacitor, Cf.
Figure 5.1
Therefore, the constant current, If. In Cf builds a linear voltage ramp across Cf. then
output voltage is thus an integral of the input current, which is forced to charge Cf by
the feedback loop. The change in voltage across Cf is
-δEo=Iin δ t/ Cf
Which makes the output change per unit to time. δEo/δ t = Ein/δ Rin
input impedance of this circuit will be Rin
NAME OF LABORATORY:
LAB SUBJECT CODE:
NAME OF DEPARTMENT:
EDC Lab
CS-302
Electronics and Comm.
PROCEDURE
1.
2.
3.
4.
Make circuit connection as shown in fig 5.2.
Take square wave as input in millivolt range.
Observe the output waveform and note down its frequency and amplitude.
Take more readings with different values of voltages and frequency of square wave
input do repeat the process.
5. Don’t give input that the op-amp goes in saturation.
Figure 5.2 Practical Circuit Diagram of Integrator Amplifier
RESULT:
NAME OF LABORATORY:
LAB SUBJECT CODE:
NAME OF DEPARTMENT:
EDC Lab
CS-302
Electronics and Comm.
EXPERIMENT NO. - 10
Operational Amplifier as Differentiator
Date of conduction:-
Date of submission:-
Submitted by other members:1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
NAME OF LABORATORY:
LAB SUBJECT CODE:
NAME OF DEPARTMENT:
EDC Lab
CS-302
Electronics and Comm.
OBJECTIVE: To the study of operational amplifier as a Differentiator circuit.
APPARATUS REQUIRED:
S.No. Name of Instruments/Kit
Specifications
Quantity
1.
Operational Amplifier Trainer kit
OAD-14
01
2.
Dual Trace Cathode Ray Oscilloscope
30 MHz
01
3.
Function Generator
30 MHz
01
4.
BNC Cable
75 Ω
03
5.
Patch Chords
Banana Pin
08
THEORY
Differentiator circuit is shown in Fig in this circuit; the positions of R and C are
reversed from those in the integrator, placing the capacitive element in the input
network. Thus the input current is made to be proportional to the rate of change
of the input voltage.
Figure 6.1
Iin= δ VinCin/δt
Again,
If = Iin
And since, -Vo = If Rf
Or
Vo = - If Rf
Eo = δ VinRfCin / δt
Vo = Ein
Gain = 1
NAME OF LABORATORY:
LAB SUBJECT CODE:
NAME OF DEPARTMENT:
EDC Lab
CS-302
Electronics and Comm.
Input impedance = ∞
A special modification of the non-inverting amplifier is the unit gain stage as
shown in Fig in this circuit, Rin has increased to infinity, Rf is zero, and the
feedback is 100%. Vo is then exactly equal to Vin. The circuit is known as a voltage
follower since the output is a unity gain, in phase replica of the input voltage. The
input impedance of this stage is also infinite.
Figure 6.2 Practical Circuit Diagram of Differentiator Amplifier
PROCEDURE
1. Make circuit connection as shown in fig 5.2.
2. Take square wave as input in millivolt range.
3. Observe the output waveform and note down its frequency and
amplitude.
4. Take more readings with different values of voltages and
frequency of square wave input do repeat the process.
5. Don’t give input that the op-amp goes in saturation.
RESULT:-
NAME OF LABORATORY:
LAB SUBJECT CODE:
NAME OF DEPARTMENT:
EDC Lab
CS-302
Electronics and Comm.
NAME OF LABORATORY: Electronics Devices
LAB SUBJECT CODE: EC-302
NAME OF DEPARTMENT: ECE Dept.
Experiment No. -11
Astable Multivibrator
Date of conduction:-
Date of submission:-
Submitted by other members:-
1.
2.
3.
4.
5.
6.
7.
8.
Group no:-
Signature
Name of faculty in charge:
Name of Technical Assistant:
Page 1 of 6
NAME OF LABORATORY: Electronics Devices
LAB SUBJECT CODE: EC-302
NAME OF DEPARTMENT: ECE Dept.
OBJECT:- To design, fabricate and test an Astable Multivibrator.
APPARATUS REQUIRED:- Trainer kit (IC-555, Vcc=10v,Diff. resistance & capacitor),CRO, Patch
cords, CRO Cords, Multi meter.
THEORY:If the circuit on the panel is connected as shown in fig., it will trigger itself and free run as an
astablemultivibrator. The trigger socket (pin-2) is connected to the threshold terminal (pin-6) to ensure
oscillation. When ‘Vcc’ is first applied to the circuit (time t=0), capacitor ‘CT’ charges to 2/3 Vcc
through ‘RA’ & ‘RB’ during time ‘T2’. The delay cycle can be controlled by selecting values for ‘RA’
and ‘RB’ as the voltage on ‘CT’ swings between 2/3 Vcc and 1/3 Vcc. Therefore the frequency of
oscillations depends only on the passive components ‘RA’ ‘RB’ and ‘CT’ and is independent of Vcc.
Figure 11.1
Page 2 of 6
NAME OF LABORATORY: Electronics Devices
LAB SUBJECT CODE: EC-302
NAME OF DEPARTMENT: ECE Dept.
t1 = 0.685 (RA+RB) CT------------------1
and the discharge time(output low) by:
t2 = 0.685 RB CT
Thus the total period is given by
T= t1+ t2 = 0.685 (RA+2RB) CT -------2
The frequency of oscillations is then:
F = 1/T = 1.46/ (RA+2RB) CT -----------3
And may be easily found by fig.
Duty cycle is the ratio of the ON duration to the total duration of a cycle and is given by:
D= ON DURATION / TOTAL DURATION
= 0.685 (RA + RB) CT / 0.685 (RA + 2RB) CT
= RA+RB / RA + 2RB----------------4
It can be expressed in percentage also.
DESIGN CONSIDERATIONS
Suppose we have to design an Astable Multivibrator of Duty cycle
D= 2/3 with timing t1 = 1.370 ms and t2 = 0.685 ms
Then from equation (4)
2/3 = RA+RB / RA+2RB
Hence RA=RB
hence equation (1)
-3
1.370 x 10 = 0.685 ( RA + RB ) CT
-3
0.685 x 10 = 0.685 RB CT
-3
-3
or RB CT = 10 or CT = 10 / RB
Assume
RA = RB = 10K
CT = .1µF
And
Page 3 of 6
NAME OF LABORATORY: Electronics Devices
LAB SUBJECT CODE: EC-302
NAME OF DEPARTMENT: ECE Dept.
Hence the calculate values of the component are:
RB = 10K Ohms and CT = 0.1µF
PROCEDURE:(A) For Astable Multivibrator having duty cycle of more than 50%
(1) Connect the circuit components using patch cords as shown in fig.
Use IC 1(555 timer) for the purpose
(2) Observe the output between the terminals 3 and ground on CRO
The output should be as shown in fig.
(B) For Astable Multivibrator having duty cycle of less than 50%
(1) Connect the circuit components using patch cords as shown in fig. for this utilize IC1 on the
panel.
(2) Observe the output between the terminals 3 and ground on CRO . It should be as indicated in fig.
(C) For Astable Multivibrator with duty cycle Variable from 0 to 100% and frequency constant.
(1) Connect the circuit components using patch cords as shown in fig.
(2) Very the duty cycle from 0 to 100% by potentiometer and observe the O/P on CRO.
OBSERVATION:- Observe the output waveform between the pin-3 and ground on CRO. Wave form at
the output should be as shown in fig.
RESULT:Precautions:1. Patch cords should be properly connected.
2. Power supply should be on after completed the connections.
Lab Quiz :Q.1 A monostable 555 timer has the following number of stable states:
(A) 0
(C) 2
(B) 1
(D) 3
Q.2 An astable 555 timer has the following number of stable states:
(A) 0
(C) 2
(B) 1
(D) 3
Q.3 An astable multivibrator requires:
(A) balanced time constants
(B) balanced time constants
(C) balanced time constants
Page 4 of 6
NAME OF LABORATORY: Electronics Devices
LAB SUBJECT CODE: EC-302
NAME OF DEPARTMENT: ECE Dept.
(D) balanced time constants
Q.4 What is another name for a bistable multivibrator?
(A) on-off switch (B) on-off switch
(C) on-off switch
Q.5 What is the difference between an astable multivibrator and a monostable multivibrator?
(A) The astable is free running. (B) The astable is free running.
(C) The monostable is free running (D) none of the above
Q.6The pulse width out of a one-shot multivibrator increases when the
(A)supply voltage increases
(C) timing resistor decreases
(B) timing resistor decreases
(D) timing capacitance increases
Q.7When a capacitor charges:
(A)the voltage across the plates rises exponentially
(B)the voltage across the plates rises exponentially
(C)the capacitor charges to the source voltage in 5RC seconds
(D)all of the above
Q.8 The _____ is defined as the time the output is active divided by the total period of the output signal.
(A)on time
(B)off time
(C)duty cycle
(D)active ratio
Q.9 The output of the astable circuit _____.
(A) constantly switches between two states
(B) constantly switches between two states
(C) is high until a trigger is received
(D) floats until triggered
Page 5 of 6
NAME OF LABORATORY: Electronics Devices
LAB SUBJECT CODE: EC-302
NAME OF DEPARTMENT: ECE Dept.
Q.10 The monostable multivibrator circuit is not an oscillator because _____.
(A) its output switches between two states
(B) its output switches between two states
(C) it requires a sine wave input signal
(D) it requires a sine wave input signal
Further reading resources:
Book: Lab experiment related theory available in following books:
Book Name
1. Electronics devices and circuits theory
2. Integrated electronics
3.Electronic Devices and Circuits, PHI
4. Microelectronics, Oxford Press.
5. Electronic Circuits Analysis and Design
Author
Boylestad
Millman
Graham Bell
Sendra and Smith
Donald A Neamen
Web resources:
1. coefs2.njit.edu
2. eecs.oregonstate.edu/education/docs/ece111/CompleteManual.pdf
3. forum.jntuworld.com
4. www.vidyarthiplus.com
5. www.svcetedu.org
Page 6 of 6
Page No.