Here are the key steps to design a variable gain audio amplifier using LM380: 1. The LM380 is an audio power amplifier that can provide a gain of up to 200. It is powered by a supply voltage between 4-15V. 2. A potentiometer is used to provide a variable gain from 1 to 50. The potentiometer is connected between the non-inverting and inverting inputs of the LM380. Turning the potentiometer varies the voltage division and thus the gain. 3. The audio input signal is given to the non-inverting terminal. A coupling capacitor is used to block any DC from the signal source and allow only the AC audio signal to pass.

1. Jawaharlal Nehru Engineering College
Laboratory Manual
ELECTRONIC SYSTEM DESIGN
For
Third Year Students
Manual made by
Prof. F. I. Shaikh
Prof. S. D. GIRI
© Author JNEC, Aurangabad

2. Jawaharlal Nehru Engineering College
Technical Document
This technical document is a series of Laboratory manuals of Electronics &
Telecommunication and is a certified document of Jawaharlal Nehru Engineering College.
The care has been taken to make the document error free but still if any error is found
kindly bring it to the notice of subject teacher and HOD.
Recommended by,
HOD
Approved by,
Principal
Copies:
• Departmental Library
• Laboratory
• HOD
• Principal

3. FOREWORD
It is my great pleasure to present this laboratory manual for third year engineering
students for the subject of Electronic System Design keeping in view understanding
required for designing, testing and working of different electronics circuits.
As a student, many of you may be wondering with some of the questions in your
mind regarding the subject and exactly what has been tried is to answer through this
manual.
Faculty members are also advised that covering these aspects in initial stage itself, will
greatly relived them in future as much of the load will be taken care by the enthusiasm
energies of the students once they are conceptually clear.
H.O.D.

4. LABORATORY MANUAL CONTENTS
This manual is intended for the Third year students of Engineering in the subject of
Electronic System Design. This manual typically contains Practical/Lab Sessions related to
Electronics covering various aspects related to the subject to enhance understanding.
Students are advised to thoroughly go through this manual rather than only topics
mentioned in the syllabus, as practical aspects are the key to understanding conceptual
visualization of theoretical aspects covered in the books.
Good Luck for your Enjoyable Laboratory Sessions.
Prof. S. D. GIRI

5. SUBJECT INDEX:
1. Do’s and Don’ts in Laboratory.
2. Lab Exercises
1 . Design of Regulated Power supply for fixed voltage using IC 7805
2. Design of Regulated Power supply for variable voltage using LM 317.
3. To design an Instrumentation Amplifier.
4. To Design variable gain(1-50)audio power amplifier using LM380.
5. Design a tone control circuit with f B =30 Hz & fT=10 KHz and ± 20 dB
Maximum boost/cut at both ends.
6 .To design Decade Counter using IC 7490.
7. To Design Finite State Machine Mealy / Moore
8. To Study Data Acquisition System for parameters like : Temperature,
Pressure, Light
9. Build and test an electronic circuit on PCB.
3. Quiz on the subject
4. Conduction of Viva-Voce Examinations
5. Evaluation and marking system

6. 1.Do’s and Don’ts in Laboratory:
1. Do not handle any equipment before reading the instructions/Instruction manuals
2. Read carefully the power ratings of the equipment before it is switched on whether
ratings 230V/50Hz or 115V/60 Hz. For Indian equipments, the power ratings are
normally 230V/50Hz. If you have equipment with 115/60 Hz ratings, do not insert power
plug, as our normal supply is 230V/50 Hz, which will damage the equipment.
3. Observe type of sockets of equipment power to avoid mechanical damage
4. Do not forcefully place connectors to avoid the damage
5. Strictly observe the instructions given by the teacher/Lab Instructor
Instruction for Laboratory Teachers:
1. Submission related to whatever lab work has been completed should be done during
the next lab session.
2. The promptness of submission should be encouraged by way of marking and
evaluation patterns that will benefit the sincere students.

7. Experiment No.1
Aim: Design of Regulated Power supply for fixed voltage using IC 7805
Apparatus: Step down transformer, Diodes, capacitors, IC 7805,wires,bread board.
Circuit Diagram:
Theory: Write Specifications & applications of IC 7805.
Transformer :
Selecting a suitable transformer is of great importance. The current rating and the
secondary voltage of the transformer is a crucial factor.
• The current rating of the transformer depends upon the current required for the
load to be driven.
• The input voltage to the 7805 IC should be at least 2V greater than the required
output, therefore it requires an input voltage at least close to 7V.
• So chose a 6-0-6 transformer with current rating 500mA (Since 6*√2 = 8.4V).
NOTE : Any transformer which supplies secondary peak voltage up to 35V can be used but
as the voltage increases size of the transformer and power dissipation across regulator
increases.

8. Rectifying circuit :
The best is using a full wave rectifier
• Its advantage is DC saturation is less as in both cycle diodes conduct.
• Higher Transformer Utilization Factor (TUF).
• 1N4007 diodes are used as its is capable of withstanding a higher reverse voltage
of 1000v whereas 1N4001
Voltage regulator :
As we require a 5V we need LM7805 Voltage Regulator IC.
7805 IC Rating :
• Input voltage range 7V-
• Current rating Ic = 1A
• Output voltage range V
Capacitors :
Knowledge of Ripple factor is essential while designing the
It is given by
• Y=1/(4√3fRC) (as the capacitor filter is used)
1. f= frequency of AC ( 50 Hz)
The best is using a full wave rectifier
advantage is DC saturation is less as in both cycle diodes conduct.
Utilization Factor (TUF).
diodes are used as its is capable of withstanding a higher reverse voltage
1N4001 is 50V
ire a 5V we need LM7805 Voltage Regulator IC.
- 35V
VMax=5.2V ,VMin=4.8V
Knowledge of Ripple factor is essential while designing the values of capacitors
(as the capacitor filter is used)
advantage is DC saturation is less as in both cycle diodes conduct.
diodes are used as its is capable of withstanding a higher reverse voltage
values of capacitors

9. 2. R=resistance calculated
R= V/Ic
V= secondary voltage of transformer
• V=6√2=8. 4
• R=8.45/500mA=16.9Ω standard 18Ω chosen
3. C= filtering capacitance
We have to determine this capacitance for filtering
Y=Vac-rms/Vdc
Vac-rms = Vr/2√3
Vdc= VMax-(Vr/2)
Vr= VMax- VMin
• Vr = 5.2-4.8 =0. 4V
• Vac-rms = .3464V
• Vdc = 5V
• Y=0 .06928
Hence the capacitor value is found out by substituting the ripple factor in Y=1/(4√3fRC)
Thus, C= 2314 µF and standard 2200µF is chosen
Datasheet of 7805 prescribes to use a 0.01µF capacitor at the output side to
avoid transient changes in the voltages due to changes in load and a 0.33µF at the input
side of regulator to avoid ripples if the filtering is far away from regulator.
Conclusion: Output is constant and same as per design. Output is found to be regulated
hence components selected are correct.

10. Experiment No.2
Aim: Design of Regulated Power supply for variable voltage using LM 317.
Apparatus: Step down transformer, Diodes, capacitors, LM 317, potentiometer, wires,
Circuit Diagram:
Theory: Write Specifications & applications of LM317.
Transformer :
Selecting a suitable transformer is of great importance. The current rating and the
secondary voltage of the transformer is a crucial factor.
• The current rating of the transformer depends upon the current required for the
load to be driven.
• The input voltage to the LM 317 IC should be at least 3V greater than the required
20V output, therefore it requires an input voltage at least close to 23V.
• So chose a 18-0-18 transformer with current rating 500mA (Since 18*√2 = 25.4V).
NOTE : Any transformer which supplies secondary peak voltage up to 35V can be used but
as the voltage increases size of the transformer and power dissipation across regulator
increases.

11. Rectifying circuit :
1N4007 diodes are used as its is capable of withstanding a higher reverse voltage of
1000v whereas 1N4001 is 50V
Voltage regulator
Example: Design a voltage Regulator using IC 317 for Vo = 2V-20V & Io = 1 A.
Vo = 1.25(1 + R1/R2)*Iadj R1
Iadj = 100*10-6
R2 = 240 Ω
When Vo = 20V
Hence R1 = 3.5 K Ω and
When Vo = 2V
Hence R1 = 0.141 K Ω
I1 = Vref/R2
= 1.25/240 = 5.2 mA

12. Select a pot 5 K Ω for R1
Output Voltage Parameter Theoretical Value Standard Value
2V R1 0.141 K Ω =141 Ω 200Ω
20 V R1 3.53K Ω 5 K pot
Conclusion: Output voltage is Variable and Regulated same as per design,
Hence component selected are correct.

13. Experiment No.3
Aim : To design an Instrumentation Amplifier.
Apparatus: Bread Board, IC 741, Power Supply, Multimeter, Connecting wires
etc.
Circuit Diagram:
Fig: Instrumentation Amplifier
Vo
-12V
-12V
+V
12V
+V
12V
-12V
+V
12V
+
-
Vs2
10mV
+
-
Vs1
10mV
RG
100k 40%
+
+
+
R1
10k
R3
51k
RGA
50ohm
R3
51k
R2
10k
R2
10k
R1
10k

14. Theory: Write Specifications & applications of Instrumentation Amplifier.
Example: Design an Instrumentation Amplifier with variable gain of
2≤ A ≤ 2000 by means of 100KΩ pot.
Gain A = (1 +2 R3/RG)(R2/R1)
Let R1 = R2 = 10 KΩ, ¼ Watt.
Maximum Gain, Ama x = (1 +2 R3/RGA)
2000 = (1 +2 R3/RGA)
2R3/ RGA = 1999 ------------(1)
Minimum Gain, Am i n = (1 +2 R3/ RG +RGA)
2 = (1 +2 R3/100KΩ+RGA)
2R3/ 100KΩ+RGA =1
2R3 = 100KΩ+RGA
Put the value of 2R3 in equation (1)
Choose RGA = 50Ω . Choose RGA = 51Ω .
Hence R3 = RGA * 1999 / 2 = 50974.5 Ω
Select R3 = 51 KΩ
Connect V1 & V2 input terminals & give an input DC = 10mV.
Vin DC = 10mV.
Keep the pot at min and max position and measure the output
voltage. Verify theoretical & practical result.
Observation Table:
Vin Vout (Max)
Practical
Vout (Min)
Practical
Vout (Max)
Calculated
Vout (Min)
Calculated
10mV
20mV
Vout (Max) = (1 +2 R3/RGA)* Vin
Vout (Min) = (1 +2 R3/RGA+ RG)* Vin
Conclusion: Thus instrumentation amplifier is designed, constructed
and gain is verified.

15. Experiment No. 4
Aim: To Design variable gain(1-50)audio power amplifier using LM380.
Apparatus: Bread Board, IC LM 380, Resistors, Capacitors, Speaker, Power Supply,
Function Generator, CRO, Connecting wires etc.
Circuit Diagram:
Fig: LM 380 for variable gain 50
Fig: Pin Configuration of IC LM380

16. Theory: Write Specifications & applications of IC LM 380.
The variable gains up to 50 are obtained by use
Of potentiometer across the two input terminals as shown in
figure. At the output of amplifier a speaker of 8 Ω is
connected through a coupling capacitor of 500 µF and to and
suppress undesirable oscillations RC network is connected at
output with 2.7Ω and 0.1 µF.
Procedure: 1. Assemble the circuit
2. Give a Sine wave input of 10 mV peak to peak at the input.
Conclusion: The gain of the circuit is 1-50 which can be increased by using positive feedback.

17. Experiment
Aim: Design a tone control circuit
boost/cut at both ends.
Apparatus: Bread Board, IC LM 833, Resistors, Capacitors, Power Supply, Function Generator, CRO,
Connecting wires etc.
Theory: Write Specifications & applications of
Design: Design the active tone
Treble Frequency and maximum boost/cut
1. Assume the value of
Fig: Active tone control circuit
Experiment No. 5
circuit with f B =30 Hz & fT=10 KHz and ± 20 dB Maximum
Bread Board, IC LM 833, Resistors, Capacitors, Power Supply, Function Generator, CRO,
Write Specifications & applications of IC LM 833.
tone control for given value of Bass frequency,
and maximum boost/cut at both ends.
Let
fB - Bass frequency,
fT - Treble frequency,
AB - Bass gain
AT - Treble gain
of R2 & calculate the value of R1.
Fig: Active tone control circuit
Maximum
Bread Board, IC LM 833, Resistors, Capacitors, Power Supply, Function Generator, CRO,
frequency,

18. AB = (R1 + R2) / R1
2. R5 = R1
3. Calculate the value of R3 using
(R1 + R3 + 2R5 ) / R3
4. Select the value of R4 using
R4 ≥ R1 + R3 + 2R5
5. C1 = 1 / 2πR2fB
6. C2 = 1 / 2πR3fT
`
Procedure:
1. Design the circuit using given formulae.
2. Implement the circuit as shown in the circuit diagram.
3. Vary the input frequency & measure the output voltage.
4. Draw the frequency response on a semi log paper.
Conclusion: The gain of this circuit can be varied by using variable resistors.

19. Experiment No.6
Aim : To design Decade Counter using IC 7490.
Apparatus : Power Supply, Digital Trainer kit, IC 7490,Connecting Wires,
Function Generator, etc.
Circuit Diagram :
Theory: Write Specifications & applications of IC 7490.
Design : Design a decade up counter using JK Flip Flop.
Procedure :
1. Draw block diagram, truth table and pin diagram of 7490 IC.
2. According to pin assignment, connections are done.
3. Note down output reading.
Fig: Circuit Diagram of Decade counter

20. Truth Table for Decade Counter
Clock
pulse
Input
QD QC QB QA
0 0 0 0 0
1 0 0 0 1
2 0 0 1 0
3 0 0 1 1
4 0 1 0 0
5 0 1 0 1
6 0 1 1 0
7 0 1 1 1
8 1 0 0 0
9 1 0 0 1
Conclusion: By using IC 7490 we have designed decade counter which count binary
number from 0000 to 1001.

21. Experiment No. 7
Aim: To Design Finite State Machine Mealy / Moore
Apparatus: Power Supply, Digital Trainer Kit, IC 7404,7474,7410,7411, Connecting wires,
Clock Pulse Generator, etc.
Design: Design a sequence detector circuit to detect a serial input sequence of 1010. It
should produce an output 1 when the input pattern has been detected.
Input 1 0 1 0 1 0 1 0
Output 0 0 0 1 0 1 0 1
Circuit Diagram:
Y
X
CLK
D
CP Q
_
Q
D
CP Q
_
Q

22. Theory: Write Specifications & applications of IC 7404, IC 7410, IC 7411,
IC 7474.
Procedure:
1) Draw state Diagram, Truth Table, Circuit Diagram.
2) According to pin assignment , connections are done.
3) Note down output.
Conclusion: By using ICs 7404,7474,7410 and 7411 we have designed a sequence
detector.
IC 7404 IC 7410
IC 7411 IC 7474

23. Experiment No.8
Aim: To Study Data Acquisition System for parameters like : Temperature, Pressure,
Light.
Theory:
Data Acquisition System
There are nearly as many systems for acquiring data as there are types of data. However,
study of this experiment confines itself to a particular class of data acquisition system,
defined as: an electronic instrument, or group of interconnected electronic hardware
items, dedicated to the measurement and quantization of analog signals for digital analysis
or processing.
Data acquisition is the process of sampling signals that measure real world physical
conditions and converting the resulting samples into digital numeric values that can be
manipulated by a computer. Data acquisition systems, abbreviated by the
acronyms DAS or DAQ, typically convert analog waveforms into digital values for
processing. The components of data acquisition systems include:
• Sensors, to convert physical parameters to electrical signals.
• Signal conditioning circuitry, to convert sensor signals into a form that can be
converted to digital values.
Analog-to-digital converters, to convert conditioned sensor signals to digital values.
Figure 1: Basic Data Acquisition System Block Diagram

24. Analog Multiplexer:
The analog multiplexer permits a number of signal sources to be automatically measured by
the same data acquisition hardware. It consists of a series of switches whose inputs are
tied to the various analog signals and whose outputs are tied to a common measuring point.
Each input is individually connected to the measuring point in a predetermined sequence.
The number of channels in a multiplexer may vary from two to several hundred.
Signal Conditioning:
Very often the signals presented to the inputs of the data acquisition system are
not in a form appropriate for conversion, and so they must be preconditioned. The required
signal conditioning could consist of linear amplification, logarithmic amplification, filtering,
peak detection, or sample-and-hold. Often more than one of these functions is acquired.
For instance, it is not uncommon to combine amplification with filtering or to find a low-
level amplifier before a sample-and-hold.
Analog-to-Digital (A/D) Converter
The analog to digital converter actually translates the analog signal into an encoded digital
format. Of the numerous ways to perform this function, only about half-dozen techniques
have found wide acceptance. Most notable are the dual-slope integrating and the
successive approximation converters. A/D converters are often referred to by the number
of output digits they produce. In a binary system, the range is from 4 to 16 bits, while in a
binary-coded decimal system, 3 to 4 digits are normal.
Digital Clock
The digital clock provides the master timing for the data acquisition system. It may be as
simple as a multi phased crystal controlled oscillator, or it may provide the user with a
wide selection of multiplexer rates and modes of operation. Some systems also contain
both time-of-day and day-of-year clocks
Manual Data Entry
Many data acquisition systems provide users with a way to tag the data they are
accumulating, through some sort of manual data entry. They may wish to note such things
as the type of data,
Digital Buffer
The ability to record discrete events is often a requirement of a data acquisition system.
Since these events are usually accompanied by the opening or closing of a switch, they

25. represent a digital input. Out-of-tolerance conditions or some other situations that might
invalidate the data collection are most often designated as "discrete events."
Output Buffer
The output buffer acts as the data collector for the DAS. In an ordered sequence, it
gathers up such data as the multiplexer channel number, the signal conditioner gain, A/D
converter data, manual data, clock information, and discrete events. The buffer combines
the data with the proper format for entry into the recording or processing system. It
also provides the proper buffering and control to interface with the recording or
processing device.
If the processing device were a minicomputer, the output buffer might be called a
"peripheral controller."
Recording/Processing Device
A number of different equipment types can fill the role of the recording or processing
device. Some of the equipment types commonly used are paper tape punches, teleprinters
(TTY), magnetic tape units, line printers, cathode-ray tube displays, floppy disks, general-
purpose digital computers, and special-purpose digital processors.
In recent years, all these components of the data acquisition system have become more
automated; a typical block diagram can be seen in Figure 2 . All the major functions of
Figure 1 can be found. Clock information is supplied by the computer, and timing is
generated in the input/ output (I/O) controller.
Figure 2: More Automated version of DAS

26. This system configuration has two distinct advantages: first, on-line programmable
processing is possible; and second, a host of storage media is available. The rapid
expansion of the data acquisition field is directly attributable to the advent of low-cost
computer hardware, which makes systems like that of Figure 2 reality. Yet we should not
overlook the dotted-line box in the lower right-hand corner of that figure: Software can
easily become a more costly burden than the hardware.
Conclusion: Data Acquisition System can be used for acquiring physical or chemical or
position data in to system for analysis purpose.

27. Experiment No. 9
Aim: Build and test an electronic circuit on PCB.
Apparatus: Electronic circuit, electronic components, PCB , FERRIC CHLORIDE, butter
paper, drilling machine, soldering gun, soldering wire, flux
Theory:
Building and Electronic circuit on PCB:
How the electronic circuit (that you have chosen as a mini project) works?
What is the function of your mini project and its application?
How do you make a manual PCB lay out?
How do you transfer the PCB layout on PCB.
How do you carry out PCB etching?
Explain drilling, component mounting and soldering procedure.
How do you test your mini project?
Procedure: Choose a simple direct/IC- based electronic circuit as your mini project
Understand function of your electronic circuit.
Collect all required components and their data sheet.
Make a manual PCB layout.
Transfer this pattern on PCB.
Carry out etching using ferric chloride.
Carry out drilling using drilling machine.
Mount all components at their respective positions.
Solder components to complete the circuit.
Test your circuit and verify its function.
Conclusion: A electronic circuit was assembled on PCB. It was tested to verify its
function.

28. 3.Quiz on the subject:
1) How to design the transformer.
2) What are the steps to design fixed regulated power supply.
3) How to design variable regulated power supply.
4) What is an Instrumentation amplifier.
5) Explain active tone control circuit.
6) Explain Finite State Machine.
7) How to design audio power amplifier.
8) Which IC is used for counter & how to design.
9) What are the steps to design PCB.
10) What is the selection criteria for resistors and capacitors.
4. Conduction of VIVA-VOCE Examinations : -
Teacher should conduct oral exams of the students with full preparation. Normally the
objective questions with guess are to be avoided. To make it meaningful, the questions
should be such that depth of the student in the subject is tested. Oral Exams are to be
conducted in co-cordial situation. Teachers taking oral exams should not have ill thoughts
about each other & courtesies should be offered to each other in case of opinion, which
should be critically suppressed in front of the students.
5. Evaluation and marking system: -
Basic honesty in the evaluation and marking system is essential and in the process impartial
nature of the evaluator is required in the exam system. It is a primary responsibility of
the teacher to see that right students who really put their effort &intelligence are
correctly awarded.
The marking pattern should be justifiable to the students without any ambiguity and
teacher should see that students are faced with just circumstance.