Electronics for Engineers – EEE stream / BEFEC104/204

Experiment 0: Familiarize with the electronic components and equipment

Introduction

If you are new to electronics or starting to build electronic circuits, then the important thing to do is to
get familiar with a few Basic Electronic Components and Equipment. There are many electronic
components like Resistors, Capacitors, LEDs, Transistors, etc. and there are also many equipment like
a Power Supply, Oscilloscope, Function Generator (or Signal Generator), Multimeter, etc. Without
understanding these basic electronic components i.e. their values, ratings, purpose etc. your circuit
design might not function as expected.

Diodes

A diode is a non-linear semiconductor device that allows the flow of current in one direction. A Diode
has two terminals namely Anode and Cathode. The following figure shows the symbol of a Diode and
its physical appearance.

There are different types of Diodes depend up on the applications like PN Junction Diode, Light
Emitting Diode (LED), Zener Diode, Schottky Diode, Photodiode, and DIAC etc. Following table
shows different types of diodes and their applications.

Types of diodes
Name of the diode Application
PN Juction Rectifiers, clippers and clampers
GUNN Diode Generation of microwave signals
Laser Diode Used in fiber optic
communications, barcode
readers, CD/DVD drives.
Light emitting diode Lightening applications like
aviation lightening, traffic
signals, camera flashes.
Photodiode Used as high voltage rectifier,
photo detector, radio frequency
switch.
Step recovery Diode Used for generation and shaping
of high frequency pulses

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Tunnel Diode Used in microwave applications

Varactor diode Mostly used in radio frequency
applications.
Zener Diode Mostly used as voltage reference
diodes

Transistors:

Transistor, the invention that changed the future of electronic circuits. It is a semiconductor device
that can be used to either switch electrical power or amplify electronic signals. A Transistor is a 3
terminal device that can be either a current controlled device or a voltage-controlled device.
Symbol of a BJT and its physical appearance is shown below.

Transistor symbol Metal Case Transistor Plastic case transistor

Resistors

The basic component of any electronic circuit is the Resistors. It is a passive electronic component
that introduces electrical resistance in to the circuit. Using resistors, we can reduce the current, divide
voltages, setup biasing of transistors (or other active elements), etc. Physical appearance and symbol
of a resistor is shown below.

Resistor Color Code

An electronic color code is a code that is used to specify the ratings of certain electrical components,
such as the resistance in Ohms of a resistor. Electronic color codes are also used to rate capacitors,
inductors, diodes, and other electronic components, but are most typically used for resistors. Only
resistors are addressed by this calculator.
How the color coding works:
The color coding for resistors is an international standard that is defined in IEC 60062. The resistor
color code shown in the table below involves various colors that represent significant figures,
multiplier, tolerance, reliability, and temperature coefficient. Which of these, the color refers to is
dependent on the position of the color band on the resistor. In a typical four-band resistor, there is a
spacing between the third and the fourth band to indicate how the resistor should be read (from left to
right, with the lone band after the spacing being the right-most band). In the explanation below, a four-
band resistor (the one specifically shown below) will be used.

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1st Band Green = 5 (significant value)

2nd Band Red = 2 (significant value
3rd band Blue = 6 (multiplier)
4th band Gold = 5% (Tolerance)
the value of resistor = 52X106
= 52M
The value can vary between 49.4M to 54.6M

Color 1st and 2nd 3rd 4th

Multiplier Tolerance
Band Significant Figures

0 ×1
Black
1 × 10 ±1% (F)
Brown
2 × 100 ±2% (G)
Red
3 × 1K ±0.05% (W)
Orange
4 × 10K ±0.02% (P)
Yellow
5 × 100K ±0.5% (D)
Green
6 × 1M ±0.25% (C)
Blue
7 × 10M ±0.1% (B)
Violet
8 × 100M ±0.01% (L)
Grey
9 × 1G
White
× 0.1 ±5% (J)
Gold
× 0.01 ±10% (K)
Silver
±20% (M)
None

Capacitors

Another important passive components are capacitors that stores energy in the form of electric field.
Most capacitors consist of two conducting plates that are separated by a dielectric material. In
electronics circuits, a capacitor is mainly used to block DC Current and allow AC Current. The
other applications of capacitors are found in filters, timing circuits, power supplies and energy storing
elements. There are many types of Capacitors like Polarized, Non-Polarized, Ceramic, Film,
Electrolytic, Super Capacitors etc. They are basically classified in respect of the dielectric material
used. The physical appearance and symbolic representation of capacitors are shown in the following
figure.

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More examples are shown below.

Indication Value
10 10 pF
100 100 pF
101 100 pF
102 1000 pF 1 nF 0.001 µF
103 10 000 pF 10 nF 0.01 µF
104 100 000 pF 100 nF 0.1 µF
105 1000 000 pF 1000 nF 1 µF

Inductors

If capacitors store energy in the form of electric field, then inductors are devices that store energy in
the form of Magnetic Field. An inductor is nothing but a wire that is wound in the form of a coil.
Inductor is widely used in AC equipment like filters, chokes, tuned circuits etc.

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Power sources
DC Power Supply:
Bench Power Supply is an important piece of equipment when it comes to working around electronic
circuits. Electronic components majorly work on DC Power Supply and hence having a reliable source
of DC Power Supply is very important. Here are many types of Power Supplies like AC-to-DC Power
Supplies, Linear Regulators, Switching Mode Power Supply, etc. An alternative to bench power
supply is to use a wall adapter as per the project requirement like 5V or 12V. The figure shown below
is an image of a dc power supply with independent outputs of 12V, 5V and 0-30V.

Oscilloscope:

The most reliable Test Equipment for observing continuously varying signals is an Oscilloscope. With
the help of an Oscilloscope, we can observe the changes in an electrical signal like voltage, over time.
Oscilloscopes are used in a wide range of field like Medical, Electronic, Automobile, Industrial and
Telecommunication Applications.

Originally, Cathode Ray Oscilloscopes (CRO) are made up of Cathode Ray Tube (CRT) displays but
nowadays, almost all Oscilloscopes are Digital Storage Oscilloscopes (DSO) with advanced features
like storage and memory with the facility of interfacing with computer or printer. Following are the
images of a CRO and DSO.

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Basic operation and Measurement in oscilloscope

1. Plug the electrical signal you’d like to view into one of the oscilloscope’s inputs of which
there are typically two, labeled A and B or X and Y. Note that when you first switch on the
oscilloscope, the signal won’t be visible until you adjust two settings: volts/division and
time/division (or time base).
2. Adjust the intensity and focus knobs to get a clear sharp horizontal line (beam) on CRO
screen. Feed the signal to the input of the CRO.
3. When measuring the vertical scale, the volts/division determines the number of volts for each
vertical division.
4. The time/division controls the horizontal scale. The amount of time each horizontal division
shows is commensurately changed when you adjust the time/division.
5. Adjust these two settings until the signal is clearly displayed on the oscilloscope’s screen.
The figure below shows how a sine wave is displayed on CRO and its measurements.

Figure: Measurements using a Cathode Ray Oscillscope

Multimeter:

A multimeter is a combination of Voltmeter, Ammeter and Ohmmeter. They provide an easy way to
measure different parameters of an electronic circuit like current, voltage, resistance etc. Multimeters

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can measure values in both AC and DC. Earlier Multimeters are Analog and consists of a pointing
needle. Modern Multimeters are Digital and are often called as Digital Multimeters or DMMs. DMMs
are available as handheld devices as well as bench devices. Modern multimeters can measure
capacitance, inductance, h-parameters of a transistor along with current, voltage and resistance. A
Multimeter can be very handy in finding basic faults in a circuit. The following figures show different
types of multimeters.

Function Generator or Signal Generator

A Signal Generator, as the name suggests, generates a variety of signals for testing and troubleshooting
electronic circuits. The most common types of signals are Triangular Wave, Sine Wave, Square Wave
and Sawtooth Wave. Along with a bench power supply and oscilloscope, a function generator is also
an important piece of equipment when designing electronic circuits. While bench power supply can
be considered as a DC voltage source, the function/signal generator can be considered as an AC source.
Physical appearance of a function/signal generator as shown below.

Function Generator Signal Generator

In this article, we have seen a few Basic Electronic Components and Test Equipment that we come
across very frequently when designing or testing electronic circuits. There are a lot more components
like Transformers, Buttons, Switches, Connectors, etc. which we can explore as we move forward
with higher semesters.

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EXPERIMENT 1: Implement an halfwave and full wave rectifier using diode

AIM: To conduct the experiment on Half wave and full wave rectifier using IN4001

APPARATUS: Diode, resistor, transformer, CRO

CIRCUIT DIAGRAM:

Fig: HWR Circuit Diagram

PROCEDURE:

The procedure for a half wave rectifier experiment is as follows:

1. Test the transformer before applying power
2. Apply a power supply to the transformer's primary coil
3. Observe the secondary coil's AC waveform
4. Connect the circuit to the transformer's secondary terminals
5. Connect a CRO across the load
6. Set the CRO switch to "ground" mode and adjust the horizontal line to the x-axis
7. Switch the CRO to DC mode and observe the waveform
8. Note the waveform's amplitude, frequency, and Vmax

HWR Waveform:

Fig: HWR Waveform

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Full Wave Rectifier circuit:

PROCEDURE:
The procedure for a half wave rectifier experiment is as follows:
1. Test the transformer before applying power
2. Apply a power supply to the transformer's primary coil
3. Observe the secondary coil's AC waveform
4. Connect the circuit to the transformer's secondary terminals
5. Connect a CRO across the load
6. Set the CRO switch to "ground" mode and adjust the horizontal line to the x-axis
7. Switch the CRO to DC mode and observe the waveform
8. Note the waveform's amplitude, frequency, and Vmax

Full Wave Rectifier Waveform:

Fig: Full Wave Rectifier Waveform

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Experiment 2: Develop a compact and efficient 5V DC diode-based power supply

solution (Example of Mobile charger).
Aim: To develop a 5V dc supply.

Components required: Step down transformer 230/6-0-6V 50Hz, 1N4001 diode – 4 Nos., 1000 F
capacitor 1No, 0.01uF capacitor -1 No. IC7805 -1No.

Introduction: A mobile charger works on the simple principle of conversion of AC (alternating

current) to DC (direct current). To accomplish 5V output that is what exactly needed by the smart
phone it has to do step by step working: converting the AC voltage to DC voltage, regulating it,
and providing it to the output port.

Fig: 5V DC Mobile Charger Circuit

Working Principle: Figure shows circuit of a mobile charger. We know that the available power
supplied by the electricity board is in India is 230V, 50Hz called as “line voltage”. The line voltage is
first reduced to a required voltage level using a step down transformer. The primary coil of the
transformer is connected to the line voltage and the induced voltage at the secondary coil of the
transformer is connected to a bridge rectifier that is constructed by four semiconductor diodes to
convert AC to DC. The output will be a pulsating dc signal but not a pure DC. A high value of capacitor
is used reduced ac component at the output which is then connected to 5V regulator IC. Final output
will be pure dc of 5V. The output waveforms at different stages of the circuit is shown below.

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Procedure:

1. Rig up the circuit as shown in the figure.

2. Observe and record the signal shape and voltage level at different stages of output; secondary
of the transformer, rectified output without capacitor, output with capacitor before the regulator
IC and the final output.
3. Plot the output wave forms at different stages of the circuit on graph sheet.

Result:

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EXPERIMENT NO 3: Verification of Truth Tables of Logic Gates Using

Integrated Circuits
AIM: To verify the truth tables of AND, OR, NOT, EX-OR, NAND and NOR gates using
integrated circuits

COMPONENTS REQUIRED: AND gate (IC 7408), NOT gate (IC 7404), OR gate (IC 7432),
NAND gate (IC 7400), NOR gate (IC 7402), X-OR gate (IC 7486), Power supply, Digital IC
trainer kit, connecting wires.

BOOLEAN EXPRESSIONS

Pin Identification

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PROCEDURE
➢ To verify the truth table of a logic gate, the suitable IC is taken and the connections are given
using the circuit diagram.
➢ For all the ICs, 5V is applied to pin 14 while pin 7 is connected to the ground.
➢ The logical inputs of the truth table are applied, and the corresponding output is noted.
➢ Similarly, the output is noted for all other combinations of inputs.
➢ In this way, the truth table of a logic gate is verified.

RESULT
The truth table of logic gates AND, OR, NOT, Ex-OR, NAND and NOR using integrated circuits is
verified.
Precautions
(i) VCC and ground pins must not be interchanged while making connections. Otherwise the chip
will be damaged. (ii) The pin configuration for NOR gate is different from other gates

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EXPERIMENT NO 4: Design and Validate Half Adder( HA) and Half

Subtractor(HS) Using basic and universal gates
AIM: To design and verify the HA and HS Using basic and universal gates

Half adder:

Half Adder using Gates

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Half subtractor:

Procedure
1. Place the IC in the socket of the trainer kit.
2. Make the connections as per the circuit diagram.
3. Switch on VCC and apply various combinations of input according to the truth table.
4. Note down the output readings for HA and HS sum/difference and the carry/borrow bit for different
combinations of inputs.

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EXPERIMENT NO 5: Design and Validate Full Adder( FA) and Full

Subtractor(FS) Using basic and universal gates

AIM: To design and verify the FA and FS Using basic and universal gates

Full Adder:

The Boolean expression for a full adder is as follows:

For the SUM(S) bit:

For the CARRY-OUT (COUT) bit:

Full Adder using NAND gates

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Full Subtractor:

(i) Full subtractor using basic gates

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(ii) Full subtractor using NAND gates

Procedure
1. Place the IC on IC Trainer Kit.
2. Connect VCC and ground to respective pins of IC Trainer Kit.
3. Implement the circuit as shown in the circuit diagram.
4. Connect the inputs to the input switches provided in the IC Trainer Kit.
5. Connect the outputs to the switches of O/P LEDs
6. Apply various combinations of inputs according to the truth table and observe the condition of
LEDs.
7. Note down the corresponding output readings for various combinations of inputs.
8. Power Off Trainer Kit, disconnect all the wire connections and remove IC's from IC-Base.

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Experiment 6: Implement a digital circuit to perform 4-bit addition and

subtraction.

Introduction

In Digital Circuits, A Binary Adder-Subtractor is capable of both the addition and subtraction of
binary numbers in one circuit itself. The operation is performed depending on the binary value of
the control signal holds. It is one of the components of the ALU (Arithmetic Logic Unit). This
Circuit requires prerequisite knowledge of Ex-ORGate, Binary Addition and Subtraction, and Full
Adder. A Full adder can add single-digit binary numbers and carries. The largest sum that can be
obtained using a full adder is 112.

A Full adder can add single-digit binary numbers and carries. The largest sum that can be obtained
using a full adder is 112. Parallel adders can add multiple-digit numbers. If full adders are placed in
parallel, we can add two- or four-digit numbers or any other size desired. Figure below uses
STANDARD SYMBOLS to show a parallel adder capable of adding two, two-digit binary numbers
The addend would be on A inputs, and the augend on the B inputs. For this explanation we will
assume there is no input to C0 (carry from a previous circuit)

Figure: Block diagram of a 4-bit adder using two full adders in parallel

For example, to add 102 (addend) and 012 (augend), the addend inputs will be 1 on A2 and 0 on A1. The
augend inputs will be 0 on B2 and 1 on B1. Working from right to left, as we do in normal addition, let’s
calculate the outputs of each full adder. With A1 at 0 and B1 at 1, the output of adder1 will be a sum (S1) of 1
with no carry (C1). Since A2 is 1 and B2 is 0, we have a sum (S2) of 1 with no carry (C2) from adder1. To
determine the sum, read the outputs (C2, S2, and S1) from left to right. In this case, C2 = 0, S2 = 1, and S1 = 1.
The sum, then, of 102 and 012 is 0112. To add four bits we require four full adders arranged in parallel. IC
7483 is a 4- bit parallel adder whose pin diagram is shown.

MSB LSB

INPUTS Cin

A3 A2 A1 A0

B3 B2 B1 B0

OUTPUT Cout S3 S2 S1 S0
Figure: Pin diagram of IC 7483 –
a 4-bit full adder

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Aim: To design and set up the following circuit using IC 7483.

i) A 4-bit binary parallel adder.
ii) A 4-bit binary parallel subtractor.

i) 4-Bit Binary Adder

An Example: 7+2=11 (1001)

7 is realized at A3 A2 A1 A0 = 0111
+2 is realized at B3 B2 B1 B0 = 0010
Sum = 1001

Figure: A 4-bit adder circuit with its realization with an example

Components Required: Digital IC Trainer Kit, IC 7483 – 1No, Patch chords.

Procedure:

1. Check all the components for their working.

2. Insert the appropriate IC into the IC base.
3. Use logic input pins to make connections as shown in the circuit diagram.
4. Apply augend and addend bits on A and B and Cin=0.
5. Apply different values of 4 bit sample input data using the following truth table of 4-bit adder
and record the output and verify them.

A3 A2 A1 A0 B3 B2 B1 B0 S3 S2 S1 S0

ii) 4-bit binary subtractor.

Circuit diagram for 4-bit subtractor is shown in the following figure.

Figure: 4-bit Subtractor using IC 7483 and IC 7486

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Subtraction is carried out by adding 2’s complement of the subtrahend. Example: 8 – 3 = 5 (0101)

8 is realized at A3 A2 A1 A0 = 1000
3 is realized at B3 B2 B1 B0 through X-OR gates = 0011
Output of X-OR gate is 1’s complement of 3 = 1100
2’s Complement can be obtained by adding Cin =1

Therefore
Cin = 1
A3 A2 A1 A0 = 1 0 0 0
B3 B2 B1 B0 = 1 1 0 0
S3 S2 S1 S0 = 0 1 0 1
Cout = 1 (Ignored)

Procedure:
1. Check all the components for their working.
2. Insert the appropriate IC into the IC base.
3. Make connections as shown in the circuit diagram.
4. Apply Minuend and subtrahend bits on A and B and cin=1.
5. Verify the results and observe the outputs.

Result:

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Experiment No. 7: Design a circuit to convert the following waveform: (a) Triangle to Square
(b) Sine to Cosine (c) Square to Triangular

i) Triangle to Square

Introduction : When a triangle wave input is applied to a differentiator circuit it generates square
wave in the output. A differentiator circuit can be built using operational amplifier, one resistor and a
capacitor. A differentiator gives differential output of given input. So when triangle wave given as an
input, it is differentiated and square wave output is produced. An op-amp differentiator is an inverting
amplifier, which uses a capacitor in series with the input voltage. Differentiating circuits are usually
designed to respond for triangular and rectangular input waveforms. A simple Op-amp differentiator
circuit is shown below.
A triangle wave of around 10 KHz with at least 2 Vpp (-1 V to +1 V) is applied at the input. This input
is differentiated because output equation is

dVi
VO = RC
dt
So during positive ramp the output remains fixed at –Vee and during negative ramp the output will be
+Vcc· Thus the output switches from +Vcc to –Vee and so on, which means the output is a square
wave. The input and output waveforms are shown below.

Figure: Triangular wave to Square wave converter circuit and its waveforms

Differentiators have frequency limitations while operating on sine wave inputs; the circuit attenuates
all low frequency signal components and allows only high frequency components at the output. In
other words, the circuit behaves like a high-pass filter.

Aim: To make circuit that converts triangular to square wave.

Design:

Let f = 1kHz, then T=1mS. Consider C as 0.1µF, Since T=RC, then R=1kΩ.

Components Required: Op-amp 741 IC, Resistor 1kΩ – 1No, Capacitor 0.1µF – 1No, ±12V DC
power supply, Signal Generator, Oscilloscope.

Procedure:

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1. Rig up the circuit as shown in the figure.

2. Connect 12V DC power supply at pin 7 and pin 4 of op-amp.
3. Apply triangular wave signal from a signal generator set to 4V(p-p) of 1KHz as Vi.
4. Observe the input and output wave forms and record.
5. Check the input triangular wave is transformed to a Square wave on an Oscilloscope.
6. Record the values of input and output amplitudes.
7. Change the frequency and observe the input and output wave forms.

ii) Sine to Cosine

Mathematically speaking, the output signal of a Differentiator is the first order derivative of the input
signal. For example, if the input signal is a ramp, then the output of the circuit with an Operational
Amplifier as Differentiator will be simple DC (as the rate of change of ramp signal is constant).
Similarly, if the input signal is a sinusoid, then the output signal is also a sinusoid but with phase
difference of 90o. That means if a sinusoidal wave is applied to a differentiator, it is converted in to
cosine wave.
For sine wave input, which is mathematically represented as V (t) = V m sin ωt, where Vm is the
amplitude of the input signal and t is the period, the output of the differentiator is given as,
Vout = −C1 R f {d(Vm sin ωt)/dt}
For simplicity, let us assume the product C1 Rf is unity.
Vout = −Vm ω cos ωt
Thus, the output of a differentiator for a sine wave input is a cosine wave and the input-output
waveforms are shown in the figure below.

Figure: A sine to cosine converter circuit and its waveforms

Aim: To make circuit to convert sine waveform into cosine waveform.

Design:

Let f = 1kHz, then T=1mS. Consider C as 0.1 F, Since T=RC, then R=1k .

Components Required: Op-amp 741 IC, Resistor 1k – 1No, Capacitor 0.1 F – 1No, 12V DC
power supply, Signal Generator, Oscilloscope.

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Procedure:

1. Rig up the circuit as shown in the figure.

2. Connect 12V DC power supply at pin 7 and pin 4 of op-amp.
3. Apply sine wave signal from a signal generator set to 4V(p-p) of 1KHz as Vin.
4. Observe the input and output wave forms and record.
5. Check the input waveform is transformed to a cosine wave by checking the phase difference
between them on an Oscilloscope.
6. Record the values of input and output amplitudes.
7. Change the frequency and observe the input and output wave forms.

iii) Square to Triangular

Introduction: A Triangular Wave Generator Using Op amp can be formed by simply connecting an
integrator to the square wave generator. Basically, triangular wave is generated by alternatively
charging and discharging a capacitor with a constant current. This is achieved by connecting an
integrator circuit at the output of square wave generator. Assume that V1 is high at +Vsat. This forces
a constant current (+Vsat/R) through C (left to right) to drive Vo negative linearly. When V1 is low at -
Vsat, it forces a constant current (-Vsat/R) through C (right to left) to drive Vo positive, linearly. The
frequency of the triangular wave is same as that of square wave. Although the amplitude of the square
wave is constant (± Vsat), the amplitude of the triangular wave decreases with an increase in its
frequency, and vice versa. This is because the reactance of capacitor decreases at high frequencies and
increases at low frequencies. The output voltage can be calculated from the following formula.

1 t t
dt
Vo = − ∫ V1 dt = − ∫ V1
RC 0 0 RC
The above expression can be simplified to
1
Vo = − V
jωRC 1

where ω = 2πƒ and the output voltage Vo is 1/RC times the integral of the input voltage V1 with
respect to time. Thus the circuit has the transfer function of an inverting integrator with the gain
constant of -1/RC. The minus sign ( – ) indicates a 180o phase shift because the input signal is
connected directly to the inverting input terminal of the operational amplifier. The following figure
shows an op-amp integrator circuits and its corresponding wave shapes.

Figure: Square to triangular waveform converter using Op-amp and waveforms

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Aim: Convert a square wave to triangular wave.

Design:
Using the relationship T = RC we can find the resistor and capacitor values for integrator part.
Assuming T as 1 mS and C as 0.1 μF, we get R=10 k Ω.
Components Required: Op-amp 741IC, Resistor 10k Ω, Capacitor 0.1 μF, 12V DC power supply,
Signal Generator, Oscilloscope.
Procedure:

1. Rig up the circuit as shown in the figure.

2. Connect 12V DC power supply at pin 7 and pin 4 of op-amp.
3. Apply input signal from a signal generator set to 4V(p-p) of 1KHz.
4. Observe the input and output wave and record.
5. Record the values of input and output amplitudes.
6. Change the frequency to 100Hz (10T) and observe and record the change in output wave shape and
amplitue.
7. Now change the frequency to 10kHz(0.1T) and observe and record the change in output wave shape
and amplitude.

Result:

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Experiment No. 8: Design amplifier circuits with 0° phase shift and 180° phase
shift with the gain of 10, 100.
Introduction
Amplifiers are one of the main building blocks within electronic circuits, especially analogue circuits,
where they provide an increase in the signal level. An amplifier is a term that is used to describe a
circuit that increases the level of the signal that enters it. Amplifiers are used in a variety of areas from
audio applications through to radio frequency ones. Amplifier circuit can be made using various
semiconductor devices and one of them is an operational amplifier or simply Op-amp.

One of the most used op-amp is IC 741. IC 741 is a monolithic integrated circuit, comprising of a
general purpose Operational Amplifier. It was first manufactured by Fairchild semiconductors in the
year 1963. The number 741 indicates that this operational amplifier IC has 7 functional pins, 4 pins
capable of taking input and 1 output pin. IC 741 can provide high voltage gain and can be operated
over a wide range of voltages, which makes it the best choice for use in integrators, summing
amplifiers and general feedback applications. It also features short circuit protection and internal
frequency compensation circuits built in it. This Op-amp IC comes in the following form factors:

• 8 Pin DIP Package

• TO5-8 Metal can package
• 8 Pin SOIC

Following figures shows Op-amp in 8 pin DIP package and its pinout diagram.

Op amp 741 in 8 pin DIP package Pin out diagram

Now let us take a look at the functions of different pins of 741 IC op-amp circuits:

• Pin4 & Pin7 (Power Supply): Pin7 is the positive voltage supply terminal and Pin4 is the
negative voltage supply terminal. The 741 IC draws in power for its operation from these pins.
The voltage between these two pins can be anywhere between 5V and 18V.
• Pin6 (Output): This is the output pin of IC 741. The voltage at this pin depends on the signals
at the input pins and the feedback mechanism used. If the output is said to be high, it means
that voltage at the output is equal to positive supply voltage. Similarly, if the output is said to
be low, it means that voltage at the output is equal to negative supply voltage.
• Pin2 & Pin3 (Input): These are input pins for the IC. Pin2 is the inverting input and Pin3 is
the non-inverting input. If the voltage at Pin2 is greater than the voltage at Pin3, i.e., the voltage

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at inverting input is higher, the output signal stays low. Similarly, if the voltage at Pin3 is
greater than the voltage at Pin2, i.e., the voltage at non-inverting input is high, the output goes
high.
• Pin1 & Pin5 (Offset Null): Because of high gain provided by 741 Op-Amp, even slight
differences in voltages at the inverting and non-inverting inputs, caused due to irregularities in
manufacturing process or external disturbances, can influence the output. To nullify this effect,
an offset voltage can be applied at pin1 and pin5, and is usually done using a potentiometer.
• Pin8 (N/C): This pin is not connected to any circuit inside 741 IC. It’s just a dummy lead
used to fill the void space in standard 8 pin packages.

IC 741 Specifications

The following are the basic specifications of IC 741 operational amplifier:

• Power Supply: Requires a Minimum voltage of 5V and can withstand up to 18V

• Input Impedance: About 2 MΩ
• Output impedance: About 75 Ω
• Voltage Gain: 200,000 for low frequencies (200 V / mV)
• Maximum Output Current: 20 mA
• Recommended Output Load: Greater than 2 KΩ
• Input Offset: Ranges between 2 mV and 6 mV
• Slew Rate: 0.5V/µS (It is the rate at which an Op-Amp can detect voltage changes)

The high input impedance and very small output impedance makes IC 741 a near ideal voltage
amplifier.

i) Amplifier circuit with zero degree phase shift

Amplifier circuit with zero degree phase shift is nothing but non-inverting amplifier. In non-inverting
operational amplifier configuration, the input voltage signal, ( VIN ) is applied directly to the non-
inverting ( + ) input terminal which means that the output gain of the amplifier becomes “Positive” in
value in contrast to the “Inverting Amplifier” circuit we saw in the last tutorial whose output gain is
negative in value. The result of this is that the output signal is “in-phase” with the input signal.
Feedback control of the non-inverting operational amplifier is achieved by applying a small part of
the output voltage signal back to the inverting ( – ) input terminal via a Rƒ – R2 voltage divider
network, again producing negative feedback. This closed-loop configuration produces a non-inverting
amplifier circuit with very good stability, a very high input impedance, Rin approaching infinity, as no
current flows into the positive input terminal, (ideal conditions) and a low output impedance, Rout as
shown below.

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Figure: Non-inverting Amplifier using Op-amp

Aim: To design a non-inverting amplifier using op-amp and verify.

DESIGN

The formula for a non-inverting amplifier using op-amp is

RF
AV = 1 +
R1

where, AV is the closed loop voltage gain, RF is the forward resistance and R1 in the input resistance.
From the above expression, it can be found that

RF = (AV − 1)R1

For a gain of 10, let R1 be 1k ohms, then RF will be equal to 9k ohms.

Similarly For a gain of 100, let R1 be 100 ohms, then RF will be equal to 9.9k ohms (use 10k ohms).
V R
Since AV = V O , output voltage VO = (1 + RF )
IN 1

Components required: DC Power supply ±12V and 0-30V, Signal Generator, Oscilloscope,
Connecting board, Connecting wires/patch chords, Op-amp 741 IC – 1No, Resistors 100 ohms, 1k
ohms, 10k ohms.

Procedure:

1. Rig up the circuit as shown in the figure.

2. Connect ±12V DC power supply at pin 7 and pin 4 opamp.
3. To check AC amplification connect a signal generator to VIN.
4. Vary the amplitude of the signal generator as shown in the tabular column below by keeping a
frequency of 1kHz.
5. Tabulate the input and output by observing them on an oscilloscope and verify with the design
for the required amplification.
6. Observe that output waveform is inverse of input waveform.

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ii) Amplifier circuit with 180-degree phase shift

Amplifier circuit with 180-degree phase shift is nothing but an inverting amplifier. An inverting
amplifier using op-amp is a type of amplifier using op-amp, where the output waveform will be phase
opposite to the input waveform. The input waveform will be amplifier by the factor Av (voltage gain
of the amplifier) in magnitude and its phase will be inverted. Figure shown below is an op-amp
inverting amplifier using IC741.

Figure: Inverting Amplifier using Op-amp IC 741

Aim: To design an inverting amplifier using op-amp and verify.

DESIGN

The closed loop voltage gain for an inverting amplifier using op-amp is
R
AV = R F
IN

where, AV is the closed loop voltage gain, RF is the forward resistance and RIN in the input resistance.

From the above expression, it can be found that

RF = AV RIN

For a gain of 10, let RIN be 1k ohms, then RF will be equal to 10k ohms.

Similarly For a gain of 100, let RIN be 100 ohms, then RF will be equal to 10k ohms.
V R
Since AV = V O , output voltage VO = VIN × R F
IN IN

Components required: DC Power supply 12V and 0-30V, Signal Generator, Oscilloscope,
Connecting board, Connecting wires/patch chords, Op-amp 741 IC – 1No, Resistors 100 ohms, 1k
ohms, 10k ohms.

Procedure:

1. Rig up the circuit as shown in the figure.

2. Connect 12V DC power supply at pin 7 and pin 4 of op-amp.
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3. To check AC amplification connect a signal generator to VIN.

4. Vary the amplitude of the signal generator as shown in the tabular column below by keeping a
frequency of 1kHz.
5. Tabulate the input and output by observing them on an oscilloscope and verify with the design
for the required amplification.
6. Observe that output waveform is inverse of input waveform.

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Experiment 9: Provide a mechanism to perform SISO, SIPO, PISO and PIPO using
shift registers

Introduction

In digital circuits, a shift register is a cascade of flip flops, sharing the same clock, in
which the output of each flip-flop is connected to the "data" input of the next flip- flop in
the chain, resulting in a circuit that shifts by one position of the "bit array" stored in it,
"shifting in" the data present at its input and 'shifting out' the last bit in the array, at each
transition of the clock input. More generally, a shift register may be multidimensional, such
that its "data-in" and stage outputs are themselves bit arrays; this is implemented simply by
running several shift registers of the same bit-length in parallel.

Shift registers can have both parallel and serial inputs and outputs. These are often
configured as "serial- in, parallel-out" (SIPO) or as "parallel-in, serial-out" (PISO). There
are also types that have both serial and parallel input and types with serial and parallel
output. There are also "bidirectional" shift registers which allow shifting in both
directions: L→R or R→L. The serial input and last output of a shift register can also be
connected to create a "circular shift register".

Aim: To study Shift Left, Shift Right, SIPO, SISO, PISO, PIPO operation using IC 7495.

The Pinout diagram of IC 7495 is shown below.

Figure: Pinout diagram of IC 7495

Components Required: Digital IC trainer kit, IC 7495, Patch chords

Procedure
1. Note the pins as shown below

DS : Serial input data (to be right shifted)

D3, D2 , D1 , D0 : Parallel data inputs.
M : Mode Control
Keep M 1 for loading parallel data and enable clock 2. M 0 for
loading parallel data and enable clock 1.
Clock 1: For loading parallel input data and for the operation of shift left of data, Clock 2: For
right shift of data.
Q3, Q2 , Q1 ,Q0 : Parallel outputs of the shift register.

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2. Connect PIN 14 to +5V and 7 to Gnd.

For Shift Right Operation:

Serial Input Parallel Output (SIPO) Operation

1. Mode control is set to logic ‘0’.

2. Clock 1 (Pin no.9) of IC 7495 is connected to bounceless pulser high or low.
3. To convert serial input data to parallel output, serial input data is fed to pin DS of IC 7495 one
by one after every clock pulse.
4. After four clock pulses the serial input data appears in parallel form at Q3, Q2, Q1, Q0.
Serial Input Serial Output (SISO) Operation

1. Mode control is set to logic ‘0’.

2. Clock 1 (Pin no.9) of IC 7495 is connected to clock pulse available at the trainer kit.
3. The serial input to be converted to parallel output is fed by serial input data to pin D S of IC
7495 one by one after every clock pulse.
4. After four clock pulses the serial input data appears in parallel form at Q3, Q2, Q1, Q0.
5. The next three pulses will move the data out of the shift register serially at Q0 terminal.
6. Verify the SISO and SIPO operation as shown in the following truth table with a sample data
of 1010.

Truth-Table for SIPO and SISO

Mode Clock Pulse Serial Outputs

Control Input
Data Q3 Q2 Q1 Q0
1 1 1 X X X
2 0 0 1 X X
3 1 1 0 1 X
0 Clock 1
4 0 0 1 0 1 Parallel O/p read from Q0 to Q3
Serial O/p read at Q0 from 4th Pulse to 7th Pulse
5 0
6 1
7 0

Parallel in Parallel Output (PIPO) Operation

1. Mode control is set to logic ‘1’.

2. The parallel inputs to be loaded into shift register are given to D3, D2, D1, D0 inputs of IC 7495.
3. Clock 2 (Pin no.8) of IC 7495 is connected to clock pulse and is pulsed once.
4. Now D3, D2, D1, D0 parallel inputs appears on Q3, Q2, Q1, Q0 lines.

Parallel in Serial Output (PISO) Operation

1. Mode control is set to logic ‘1’.

2. The parallel inputs to be loaded into shift register are given to D3, D2, D1, D0 inputs of IC 7495.
3. Clock 1 (Pin no.9) of IC 7495 is connected to bounceless pulser high or low.
4. With each clock pulse data shifts right by one place and hence after three clock pulses parallel
input data is converted into serial output data at Q0.

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5. Verify the PIPO and PISO operation as shown in the following truth table with a sample data
of 1010.
6. Parallel O/p read from Q3 to Q0
7. Serial O/p read at Q0 from 4th Pulse to 1st Pulse

Truth-Table for PIPO and PISO

Mode Clock Pulse Outputs

Control
D3 D2 D1 D0 Q3 Q2 Q1 Q0
Clock 2 1 0 1 0 1 1 0 1 0
0 Clock 1 2 1
3 0
4 1

Result

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Demo/ Study/Simulation Experiments

1. Demonstrate a public addressing system.

What is a PA system?
When it comes to public address system components, there are a few details you want to keep in mind,
but before we get to that, let’s first get the most basic piece of information out of the way. For those
who aren’t certain, PA stands for public address system. You’ll hear it referred to both ways.
Another thing to understand is a PA system isn’t a one and done kind of thing. There are different
types of systems, components, and details you’ll want to consider. In a moment, we’ll break down the
difference between things like all in one PA systems, modular PA systems, along with traditional
systems.
First, it’s essential to understand how a system works and what you’ll need to know before setting one
up. You probably don’t remember the days of needing to use a megaphone to announce something,
which was an upgrade from yelling those details out.
But with advanced technology, a system was created to help broadcast your words and music louder
and easier. That’s the PA system we’re all used to.
What you need to know about Public Address System Components
There are a few main pieces to a PA system. The fancy word is components, but basically, it just
means the parts that make up the entire thing.
The main components of a public address system are:
• Speakers – main speakers, subwoofers, and monitors
• Amplifiers – Needed only if using passive speakers
• Audio Mixer – Analog or Digital
• Speaker Processor
• Microphones – Dynamic or Condenser
• Effects – only used if needed
• DI Box – Direct Injection Box
• Cables and Accessories.
Here is a good analogy to explain the concept. So, if you’re making a grilled cheese sandwich, the
components would be bread, cheese, and butter. You still need to put the pieces together and cook
them, but they are the ingredients you need to build your sandwich. It works the same way with a PA
system. You need different parts that you’ll hook together to make it work.
Each piece plays a role in how the PA system works. We’re not going to get into precise details on
picking out each of these things in this article. Instead, let’s stick with the basics, so it all makes sense
when you start looking into this on your end.

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When it comes time to hook up a PA system, you’ll want to read this article about setting up a stage
sound system, as it digs into more in-depth detail. Still, it doesn’t make sense to get confused before
that.
It is smarter to understand the basics. Once you have a foundation of understanding, it’s easy to go
from there. The most significant element of hooking up a system is making sure things flow the right
way.
Traditional systems

The traditional PA systems are a good choice if you love to get into the details of picking out
just the right piece of equipment. If you’re going to geek out on the experience of selecting and
comparing each component, then this is for you.
In a traditional PA system, you buy all the components separately and then connect them
together.
You’ll also want to keep in mind that usually traditional PA systems are easier to expand if
you need more power and control over your setup.
There you have it, a basic list of needs, the different types of systems, and a basic understanding
of PA systems.

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2. Generate the Amplitude modulated wave and calculate the modulation

index for Over modulation, under modulation and 100% modulation.

Aim : a) To design and construct the Amplitude Modulation circuit for a given carrier
frequency ( say 455 kHz) and modulation frequency (say 1 kHz).

b) To study the variation in modulation index as a function of modulating

voltage amplitude.

Circuit Diagram :

Procedure :

1. The circuit is connected as shown.

2. The output and gain of the circuit tuned to carrier is checked without the modulating
signal.
3. The modulating signal is switched on and the amplitude is adjusted to about two
volts and frequency to less than or equal to 1 kHz to obtain an undistorted AM wave.
4. Keeping the carrier amplitude constant, the modulating signal amplitude is varied
in appropriate steps and the Modulation index, m is calculated as shown below.
%m= [(Emax – Emin)/ (Emax + Emin)]x100

Also the modulated power with and without modulation is calculated.

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Tabular Column :
Modulating Emax Emin Modulation Total power
Signal volts volts Index, %m Pt = Pc(1 + m2/2)
Amplitude watts
volts

Calculation :
Total power, Pt = Pc(1 + m2/2) where Pc is the carrier power . RL= 1K
Pc = (Emax + Emin)2/8RL
Un modulated power, Pt = Pc and m = 0, Emax = Emin = Ec
 Pt = Ec2/8RL
Waveforms and Graph :

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3. Demonstrate the working of a superheterodyne receiver to provide excellent

adjacent channel rejection

The super heterodyne AM receiver converts all the incoming radio frequencies into a fixed radio
frequency of lower value called intermediate frequency (IF). It uses a local oscillator of frequency
higher than the incoming carrier frequency. The first step of the receiver is to select required particular
station signal rejecting the rest of signals. The radio waves from the various stations intercepted by
the antenna are coupled to the RF amplifier. Read more on Sarthaks.com -
https://www.sarthaks.com/647989/explain-the-basic-principle-super-heterody-receiver-and-explain-
the-function-each-block

RF section: It is a tuned filter that receives the required stations by tuning the filter to right frequency
band. The output of RF stage is fed to mixer stage.

Mixer: It is a kHz device that converts carrier frequency f to a fixed IF of 455 kHz. The oscillator is
made to generate a frequency exactly 455 kHz above the incoming carrier frequency f Thus, a constant
frequency difference is maintained between local oscillator frequency and incoming RF signal. It is
possible due to ganged capacitance tuning where one of the plates of capacitors in RF amplifier, mixer
and local oscillator are connected to single shaft. Required selectivity is possible by producing IF
signal.

Local oscillator: It is a Colpitts oscillator which generates a sine wave. IF amplifier: It has two or
more stages of 455 kHz frequency tuned voltage amplifiers for giving better selectivity and stability.
All signals that are converted down that are T-f and falling within the pass band of If amplifier will be
amplified and passed on to next stage

Detector: It separates modulating signal from the AM signal. It is a diode detector which gives
excellent fidelity. It first eliminates negative half cycles of IF wave and then filters the high frequency
waves. The modulating signal is then fed to AF amplifier.

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AF Amplifier: Audio signal is first amplified using RC coupled voltage amplifier to raise its level to
drive a power amplifier.
Power amplifier: It is a push pull power amplifier designed to have a minimum bandwidth of 5kHz.
The audio power amplifier output is fed to loud speaker through impedance transformer. The loud
speaker reproduces the original information.

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