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Basic Electronics Lab Manual Sanjay Memorial Polytechnic, Sagar Basic Electronic (For First Semester Diplom Hemanth Y.R Lecturer, Dept. of E & C Sanjay Memorial Polytechnic, S r cs Lab Manual ma in Computer Science and Engineering) Sagar 1
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Page 1: Be lab-1st sem cse

Basic Electronics Lab Manual

Sanjay Memorial Polytechnic, Sagar

Basic Electronics Lab Manual(For First Semester Diploma in Computer Science and Engineering)

Hemanth Y.R Lecturer, Dept. of E & C

Sanjay Memorial Polytechnic, Sagar

Sanjay Memorial Polytechnic, Sagar

Basic Electronics Lab Manual Diploma in Computer Science and Engineering)

Sagar

1

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Basic Electronics Lab Manual

Sanjay Memorial Polytechnic, Sagar

GENERAL OBJECTIVES: No. of Hrs

On completion of the lab course, the student will be able to 96

1 Comprehend the art of Soldering

2 Understand the behavioral characteristics of passive components

GRADED EXERCISES:

SECTION -- A

STUDY EXERCISES

Note: In Study Exercises the student should become familiar with

specification of equipments & components & should draw a neat

diagram of the control panel of equipment & actual appearance in

case of components. Symbols should also be indicated wherever

applicable

1

Familiarization and precautionary measures to be taken while using

the following Equipments –

Analog multimeter, Digital multimeter, Regulated power supply

LCR Meter, Ammeters, Voltmeter and Galvanometer

Ammeters voltmeter and Galvanometer

6

2 Identification of components ----- Passive and Active components

with Symbol 6

3 Colour code--- Calculation of Resistance & Capacitance value by

colour code method 6

4 Measurement of Resistance & Capacitance value by colour codes 6

5 Soldering Practice:

Tool, Bending of Wires, Soldering of Passive and Active components 6

6 Testing of Passive Components 6

7

Familiarization, Study and Application of following Hardware

materials and symbol

FUSES --- Rewirable, Cartridge, High rupturing capacity Fuse

KEYS--- Rectangular Buttons, Spring loaded, Mechanical , Electronic

feather touch

PLUGS AND SOCKETS--- 2 pin, 3 pin, Multiple, Round type

CONNECTORS : IC and relay connector, PCB connector, BNC,

threaded neutral modular

TERMINALS ---Different sizes

CABLES --- twisted pair, co-axial cable, optical cable

CLIPS --- Crocodile , Banana

Crimping tools

6

8 Study the block diagram of UPS & SMPS & state their merits and

demerits 6

Total (Section A) 48

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SECTION -- B

Conduction Exercises:

11 Verification of Ohm's law, 3

12 Verification of Kirchhoff's Current law for D.C Circuits 3

13 Verification of Kirchhoff's Voltage law for D.C Circuits 3

14 Characteristics of junction diode (Forward & Reverse Bias) 6

15 Characteristics of Zener diode (Forward & Reverse bias) 6

16 Inverting amplifier using OP-AMP 3

17 Non-inverting amplifier using OP-AMP 3

18 Half wave rectifier - construction, calculation of ripple factor with

and without shunt capacitor filter 6

19 Full wave bridge rectifier - construction, calculation of ripple factor

with and without shunt capacitor filter 9

Total (Section B) 48

Total 96

SCHEME OF VALUATION

1 Record 5

2 Part A - Study Exercise 25

3 Part B - Write up any One Experiment (Circuit Diagram, Tabular

column, Formula ) 20

3 Construction using soldering and Conduction of Experiment 20

4 Result 10

5 Viva-Voce 20

Total 100

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Basic Electronics Lab Manual

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SECTION -- A

Study Exercises

1. Familiarization of meters.

Connecting meters

It is important to connect meters the correct way round:

• The positive terminal of the meter, marked + or coloured red should be connected

nearest to + on the battery or power supply.

• The negative terminal of the meter, marked - or coloured black should be connected

nearest to - on the battery or power supply.

Voltmeters

• Voltmeters measure voltage.

• Voltage is measured in volts, V.

• Voltmeters are connected in parallel across

components.

• Voltmeters have a very high resistance.

Measuring voltage at a point

When testing circuits you often

need to find the voltages at

various points, for example the

voltage at pin 2 of a 555 timer

IC. This can seem confusing -

where should you connect the

second voltmeter lead?

• Connect the black

(negative -) voltmeter

lead to 0V, normally the

negative terminal of the

battery or power

supply.

• Connect the red (positive +) voltmeter lead to the point you where you need to

measure the voltage.

• The black lead can be left permanently connected to 0V while you use the red lead

as a probe to measure voltages at various points.

Connecting a voltmeter in parallel

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• You may wish to use a crocodile clip on the black lead to hold it in place.

Voltage at a point really means the voltage difference between that point and 0V (zero

volts) which is normally the negative terminal of the battery or power supply. Usually 0V will

be labeled on the circuit diagram as a reminder.

Analogue meters take a little power from the circuit under test to operate their pointer. This

may upset the circuit and give an incorrect reading. To avoid this voltmeters should have a

resistance of at least 10 times the circuit resistance (take this to be the highest resistor value

near where the meter is connected).

Most analogue voltmeters used in school science are not suitable for electronics because

their resistance is too low, typically a few k . 100k or more is required for most

electronics circuits.

Ammeters

• Ammeters measure current.

• Current is measured in amps (amperes), A.

1A is quite large, so mA (milliamps) and µA

(microamps) are often used. 1000mA = 1A,

1000µA = 1mA, 1000000µA = 1A.

• Ammeters are connected in series.

To connect in series you must break the circuit

and put the ammeter across the gap, as shown

in the diagram.

• Ammeters have a very low resistance.

The need to break the circuit to connect in series means

that ammeters are difficult to use on soldered circuits. Most testing in electronics is done

with voltmeters which can be easily connected without disturbing circuits.

Galvanometers

Galvanometers are very sensitive meters which are used to

measure tiny currents, usually 1mA or less. They are used to

make all types of analogue meters by adding suitable resistors

as shown in the diagrams below. The photograph shows an

educational 100µA galvanometer for which various multipliers and shunts are available.

Connecting an ammeter in series

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Making a Voltmeter

A galvanometer with a

high resistance

multiplier in series to

make a voltmeter.

Making an Ammeter

A galvanometer with

a low resistance

shunt in parallel to

make an ammeter.

Galvanometer with multiplier and shunt

Maximum meter current 100µA (or 20µA

reverse).

This meter is unusual in allowing small

reverse readings to be shown.

Ohmmeters

An ohmmeter is used to measure resistance in ohms ( ).

Ohmmeters are rarely found as separate meters but all

standard multimeters have an ohmmeter setting.

1 is quite small so k and M are often used.

1k = 1000 , 1M = 1000k = 1000000 .

Multimeters

Multimeters are very useful test

instruments. By operating a multi-

position switch on the meter they can

be quickly and easily set to be a

voltmeter, an ammeter or an

ohmmeter. They have several settings

(called 'ranges') for each type of meter

and the choice of AC or DC.

Some multimeters have additional

features such as transistor testing and

ranges for measuring capacitance and

frequency.

Analogue multimeters consist of a

galvanometer with various resistors which can be switched in as multipliers (voltmeter

ranges) and shunts (ammeter ranges).

Analogue Multimeter Digital Multimeter

Multimeter Photographs © Rapid Electronics

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2. Electronic Components and symbols

1. ACTIVE components increase the power of a signal and must be supplied with the

signal and a source of power.

Examples are bipolar transistors, field effect transistors etc.

The signal is fed into one connection of the active device and the amplified version

taken from another connection.

In a transistor, the signal can be applied to the base connection and the amplified

version taken from the collector.

2. PASSIVE components do not increase the power of a signal.

They often cause power to be lost.

Some can increase the voltage at the expense of current, so overall there is a loss of

power.

Resistors, capacitors, inductors and diodes are examples of passive components.

Some of the active components are

1. Diodes

2. Transistors

3. Integrated circuits

4. Optoelectronic components

Similarly some of the passive components are

1. Resistors

2. Capacitors

3. Inductors

4. Sensors

5. Detectors

6. Antennas

Wires and connections

Component Circuit Symbol Function of Component

Wire

To pass current very easily from one part of

a circuit to another.

Wires joined

A 'blob' should be drawn where wires are

connected (joined), but it is sometimes

omitted. Wires connected at 'crossroads'

should be staggered slightly to form two T-

junctions, as shown on the right.

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Wires not joined

In complex diagrams it is often necessary to

draw wires crossing even though they are

not connected. The simple crossing on the

left is correct but may be misread as a join

where the 'blob' has been forgotten. The

bridge symbol on the right leaves no doubt!

Power Supplies

Component Circuit Symbol Function of Component

Cell

Supplies electrical energy.

The larger terminal (on the left) is positive (+).

A single cell is often called a battery, but strictly

a battery is two or more cells joined together.

Battery

Supplies electrical energy. A battery is more

than one cell.

The larger terminal (on the left) is positive (+).

Solar Cell

Converts light to electrical energy.

The larger terminal (on the left) is positive (+).

DC supply

Supplies electrical energy.

DC = Direct Current, always flowing in one

direction.

AC supply

Supplies electrical energy.

AC = Alternating Current, continually changing

direction.

Fuse

A safety device which will 'blow' (melt) if the

current flowing through it exceeds a specified

value.

Transformer

Two coils of wire linked by an iron core.

Transformers are used to step up (increase) and

step down (decrease) AC voltages. Energy is

transferred between the coils by the magnetic

field in the core. There is no electrical

connection between the coils.

Earth

(Ground)

A connection to earth. For many electronic

circuits this is the 0V (zero volts) of the power

supply, but for mains electricity and some radio

circuits it really means the earth. It is also

known as ground.

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Output Devices: Lamps, Heater, Motor, etc.

Component Circuit Symbol Function of Component

Lamp (lighting)

A transducer which converts electrical energy

to light. This symbol is used for a lamp

providing illumination, for example a car

headlamp or torch bulb.

Lamp (indicator

)

A transducer which converts electrical energy

to light. This symbol is used for a lamp which

is an indicator, for example a warning light on

a car dashboard.

Heater A transducer which converts electrical energy

to heat.

Motor A transducer which converts electrical energy

to kinetic energy (motion).

Bell

A transducer which converts electrical energy

to sound.

Buzzer

A transducer which converts electrical energy

to sound.

Inductor

(Coil, Solenoid)

A coil of wire which creates a magnetic field

when current passes through it. It may have

an iron core inside the coil. It can be used as a

transducer converting electrical energy to

mechanical energy by pulling on something.

Switches

Component Circuit Symbol Function of Component

Push Switch

(push-to-

make)

A push switch allows current to flow only

when the button is pressed. This is the

switch used to operate a doorbell.

Push-to-Break

Switch

This type of push switch is normally closed

(on), it is open (off) only when the button is

pressed.

On-Off Switch

(SPST)

SPST = Single Pole, Single Throw.

An on-off switch allows current to flow only

when it is in the closed (on) position.

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2-way Switch

(SPDT)

SPDT = Single Pole, Double Throw.

A 2-way changeover switch directs the flow

of current to one of two routes according

to its position. Some SPDT switches have a

central off position and are described as

'on-off-on'.

Dual On-Off

Switch

(DPST)

DPST = Double Pole, Single Throw.

A dual on-off switch which is often used to

switch mains electricity because it can

isolate both the live and neutral

connections.

Reversing

Switch

(DPDT)

DPDT = Double Pole, Double Throw.

This switch can be wired up as a reversing

switch for a motor. Some DPDT switches

have a central off position.

Relay

An electrically operated switch, for

example a 9V battery circuit connected to

the coil can switch a 230V AC mains circuit.

NO = Normally Open, COM = Common,

NC = Normally Closed.

Resistors

Component Circuit Symbol Function of Component

Resistor

A resistor restricts the flow of current, for

example to limit the current passing through

an LED. A resistor is used with a capacitor in

a timing circuit.

Some publications use the old resistor

symbol:

Variable Resistor

(Rheostat)

This type of variable resistor with 2 contacts

(a rheostat) is usually used to control

current. Examples include: adjusting lamp

brightness, adjusting motor speed, and

adjusting the rate of flow of charge into a

capacitor in a timing circuit.

Variable Resistor

(Potentiometer)

This type of variable resistor with 3 contacts

(a potentiometer) is usually used to control

voltage. It can be used like this as a

transducer converting position (angle of the

control spindle) to an electrical signal.

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Variable Resistor

(Preset)

This type of variable resistor (a preset) is

operated with a small screwdriver or similar

tool. It is designed to be set when the circuit

is made and then left without further

adjustment. Presets are cheaper than

normal variable resistors so they are often

used in projects to reduce the cost.

Capacitors

Component Circuit Symbol Function of Component

Capacitor

A capacitor stores electric charge. A

capacitor is used with a resistor in a timing

circuit. It can also be used as a filter, to

block DC signals but pass AC signals.

Capacitor,

polarised

A capacitor stores electric charge. This

type must be connected the correct way

round. A capacitor is used with a resistor

in a timing circuit. It can also be used as a

filter, to block DC signals but pass AC

signals.

Variable Capacitor

A variable capacitor is used in a radio

tuner.

Trimmer

Capacitor

This type of variable capacitor (a trimmer)

is operated with a small screwdriver or

similar tool. It is designed to be set when

the circuit is made and then left without

further adjustment.

Diodes

Component Circuit Symbol Function of Component

Diode

A device which only allows current to

flow in one direction.

LED

Light Emitting Diode

A transducer which converts electrical

energy to light.

Zener Diode

A special diode which is used to maintain

a fixed voltage across its terminals.

Photodiode

A light-sensitive diode.

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Transistors

Component Circuit Symbol Function of Component

Transistor NPN

A transistor amplifies current. It can be used with other

components to make an amplifier or switching circuit.

Transistor PNP

A transistor amplifies current. It can be used with other

components to make an amplifier or switching circuit.

Phototransistor

A light-sensitive transistor.

Audio and Radio Devices

Component Circuit Symbol Function of Component

Microphone

A transducer which converts sound to electrical

energy.

Earphone

A transducer which converts electrical energy to

sound.

Loudspeaker

A transducer which converts electrical energy to

sound.

Piezo Transducer

A transducer which converts electrical energy to

sound.

Amplifier

(general symbol)

An amplifier circuit with one input. Really it is a

block diagram symbol because it represents a

circuit rather than just one component.

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Aerial

(Antenna)

A device which is designed to receive or transmit

radio signals. It is also known as an antenna.

Meters and Oscilloscope

Component Circuit Symbol Function of Component

Voltmeter

A voltmeter is used to measure voltage.

The proper name for voltage is 'potential

difference', but most people prefer to say

voltage!

Ammeter

An ammeter is used to measure current.

Galvanometer

A galvanometer is a very sensitive meter which

is used to measure tiny currents, usually 1mA

or less.

Ohmmeter

An ohmmeter is used to measure resistance.

Most multimeters have an ohmmeter setting.

Oscilloscope

An oscilloscope is used to display the shape of

electrical signals and it can be used to measure

their voltage and time period.

Sensors (input devices)

Component Circuit Symbol Function of Component

LDR

A transducer which converts brightness (light)

to resistance (an electrical property).

LDR = Light Dependent Resistor

Thermistor

A transducer which converts temperature (heat)

to resistance (an electrical property).

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3. Colour code

Resistor values - the resistor colour code

Resistance is measured in ohms, the symbol for ohm is an omega .

1 is quite small so resistor values are often given in k and M .

1 k = 1000 1 M = 1000000 .

Resistor values are normally shown using coloured bands.

Each colour represents a number as shown in the table.

Most resistors have 4 bands:

• The first band gives the first digit.

• The second band gives the second digit.

• The third band indicates the number of zeros.

• The fourth band is used to shows the tolerance (precision) of the

resistor, this may be ignored for almost all circuits but further

details are given below.

This resistor has red (2), violet (7), yellow (4 zeros) and gold bands.

So its value is 270000 = 270 k .

On circuit diagrams the is usually omitted and the value is written 270K.

Small value resistors (less than 10 ohm)

The standard colour code cannot show values of less than 10 . To show these small values

two special colours are used for the third band: gold which means × 0.1 and silver which

means × 0.01. The first and second bands represent the digits as normal.

For example:

red, violet, gold bands represent 27 × 0.1 = 2.7

green, blue, silver bands represent 56 × 0.01 = 0.56

Tolerance of resistors (fourth band of colour code)

The tolerance of a resistor is shown by the fourth band of the colour code. Tolerance is the

precision of the resistor and it is given as a percentage. For example a 390 resistor with a

tolerance of ±10% will have a value within 10% of 390 , between 390 - 39 = 351 and 390

+ 39 = 429 (39 is 10% of 390).

The Resistor Colour Code

Colour Number

Black 0

Brown 1

Red 2

Orange 3

Yellow 4

Green 5

Blue 6

Violet 7

Grey 8

White 9

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A special colour code is used for the fourth band tolerance:

silver ±10%, gold ±5%, red ±2%, brown ±1%.

If no fourth band is shown the tolerance is ±20%.

Tolerance may be ignored for almost all circuits because precise resistor values are rarely

required.

Resistor shorthand

Resistor values are often written on circuit diagrams using a code system which avoids using

a decimal point because it is easy to miss the small dot. Instead the letters R, K and M are

used in place of the decimal point. To read the code: replace the letter with a decimal point,

then multiply the value by 1000 if the letter was K, or 1000000 if the letter was M. The letter

R means multiply by 1.

For example:

560R means 560

2K7 means 2.7 k = 2700

39K means 39 k

1M0 means 1.0 M = 1000 k

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4. Soldering

What is solder?

Traditional solder is an alloy (mixture) of tin and lead, typically 60% tin and 40% lead. It

melts at a temperature of about 200°C.

Modern lead-free solder is an alloy of tin with other metals including copper and silver. It

melts at a temperature of about 220°C.

Coating a surface with solder is called 'tinning' because of the tin content of solder.

Desoldering

At some stage you will probably need to desolder a joint to remove or re-position a wire or

component. There are two ways to

remove the solder:

1. With a desoldering pump (solder

sucker)

• Set the pump by pushing the

spring-loaded plunger down until

it locks.

• Apply both the pump nozzle and

the tip of your soldering iron to

the joint.

• Wait a second or two for the

solder to melt.

• Then press the button on the

pump to release the plunger and

suck the molten solder into the

tool.

• Repeat if necessary to remove as much solder as possible.

• The pump will need emptying occasionally by unscrewing the nozzle.

How to Solder

First a few safety precautions:

• Never touch the element or tip of the soldering iron.

They are very hot (about 400°C) and will give you a nasty burn.

• Take great care to avoid touching the mains flex with the tip of the iron.

The iron should have a heatproof flex for extra protection. An ordinary plastic flex

will melt immediately if touched by a hot iron and there is a serious risk of burns and

electric shock.

• Always return the soldering iron to its stand when not in use.

Never put it down on your workbench, even for a moment!

Using a desoldering pump (solder sucker)

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• Work in a well-ventilated area.

The smoke formed as you melt solder is mostly from the flux and quite irritating.

Avoid breathing it by keeping you head to the side of, not above, your work.

• Wash your hands after using solder.

Traditional solder contains lead which is a poisonous metal.

Preparing the soldering iron:

• Place the soldering iron in its stand and plug in.

The iron will take a few minutes to reach its operating temperature of about 400°C.

• Dampen the sponge in the stand.

The best way to do this is to lift it out the stand and hold it under a cold tap for a

moment, then squeeze to remove excess water. It should be damp, not dripping wet.

• Wait a few minutes for the soldering iron to warm up.

You can check if it is ready by trying to melt a little solder on the tip.

• Wipe the tip of the iron on the damp sponge.

This will clean the tip.

• Melt a little solder on the tip of the iron.

This is called 'tinning' and it will help the heat to flow from the iron's tip to the joint.

It only needs to be done when you plug in the iron, and occasionally while soldering

if you need to wipe the tip clean on the sponge.

You are now ready to start

soldering:

• Hold the soldering iron like

a pen, near the base of the

handle.

Imagine you are going to

write your name!

Remember to never touch

the hot element or tip.

• Touch the soldering iron

onto the joint to be made.

Make sure it touches both

the component lead and the track. Hold the tip there for a few seconds and...

• Feed a little solder onto the joint.

It should flow smoothly onto the lead and track to form a volcano shape as shown in

the diagram. Apply the solder to the joint, not the iron.

• Remove the solder, then the iron, while keeping the joint still.

Allow the joint a few seconds to cool before you move the circuit board.

• Inspect the joint closely.

It should look shiny and have a 'volcano' shape. If not, you will need to reheat it and

feed in a little more solder. This time ensure that both the lead and track are heated

fully before applying solder.

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SECTION -- B

Conduction Exercises

Experiment No. 1

Verification of Ohm's law

Aim of the Experiment:

To study the dependence of current (I) on the potential difference (V) across a

resistor and determine its resistance. Also plot a graph between V and I.

In this lab, you will verify Ohms Law for different values of voltage and

resistances. You will measure the true resistance of each resistor and the voltage applied to

each resistor. You will then calculate the predicted current through each resistor. Finally,

you will measure the actual current through each resistor to verify (or disprove!) Ohm’s

Law.

Equipments & Components Required:

1. Rheostat or Decade resistance box.

2. Regulated power supply.

3. Connecting wires.

4. Multimeter.

Theory:

The Ohm’s law states that the direct current flowing in a conductor is directly

proportional to the potential difference between its ends. It is usually formulated as V = IR,

where V is the potential difference, or voltage, I is the current, and R is the resistance of the

conductor.

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Basic Electronics Lab Manual

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Consider the circuit shown below

The resistance of that circuit would be given by R=V/I

The current flowing through the circuit would be given by

The voltage would be given by I x R

Following figure shows graph of Voltage V/s Current

Experiment:

Circuit Diagram:

Sanjay Memorial Polytechnic, Sagar

Consider the circuit shown below

The resistance of that circuit would be given by R=V/I = 24/2 = 12 ohms

The current flowing through the circuit would be given by V/IR 24/12 = 2amps

The voltage would be given by I x R = 2 x 12 = 24 volts

Following figure shows graph of Voltage V/s Current

19

24/2 = 12 ohms

V/IR 24/12 = 2amps

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Data Table:

Resistance R = 1 KΩ Resistance R = 2 KΩ

Trial

No.

Voltage V

Applied in

Volts

Current I

Thro’ R

in mili

amps

Current I

By Ohm’s

Law

I=V/R

Trial

No.

Voltage V

Applied in

Volts

Current I

Thro’ R

in mili

amps

Current I

By Ohm’s

Law

I=V/R

1 1 1 1

2 2 2 2

3 3 3 3

4 4 4 4

5 5 5 5

6 6 6 6

7 7 7 7

8 8 8 8

9 9 9 9

10 10 10 10

Calculations Here ↓:

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Procedure:

1. Before doing the connection, check all the components and equipments.

2. Make the connection as shown in the circuit diagram.

3. Keep value of Rheostat or DRB to 1 KΩ and start first set of ten trials.

4. Vary voltage applied across R from 1V to 10V and record corresponding values of

current from the ammeter.

5. Also calculate theoretical values of current using ohm’s law and record in the

data table.

6. Observe the difference between theoretical and practical values of current.

7. Repeat from step 3 by keeping value of Rheostat or DRB to 2 K Ohm.

Results:

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Verification of Kirch

Aim of the Experiment:

To verify Kirchhoff’s current law.

Equipments & Components Required:

1. Two fixed value resistors.

2. Regulated power supply.

3. Connecting wires.

4. Ammeter or Multimeter.

Theory:

Kirchhoff's first law, Kirchhoff's point rule

states that at any node (junction) in an electrical circuit, the sum of currents flowing into

that node is equal to the sum of currents flowing out of that

currents in a network of conductors meeting at a point is zero.

The current entering any junction is equal to the current leaving that junction.

i2 + i3 = i1 + i4

Experiment No. 2

Verification of Kirchhoff's Current law for D.C Circuits

To verify Kirchhoff’s current law.

Equipments & Components Required:

Two fixed value resistors.

Regulated power supply.

Multimeter.

Kirchhoff's point rule, or Kirchhoff's junction rule

at any node (junction) in an electrical circuit, the sum of currents flowing into

that node is equal to the sum of currents flowing out of that node or the algebraic sum of

currents in a network of conductors meeting at a point is zero.

The current entering any junction is equal to the current leaving that junction.

22

off's Current law for D.C Circuits

Kirchhoff's junction rule (or nodal rule)

at any node (junction) in an electrical circuit, the sum of currents flowing into

node or the algebraic sum of

The current entering any junction is equal to the current leaving that junction.

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Experiment:

Circuit Diagram:

Current Equations:

Equivalent Resistance REQU = (R1*R2) / (R1+R2)

Total Current I = V/ REQU

Current Thro’ R1 is I1 = V/ R1

Current Thro’ R2 is I2 = V/ R2

Data Table:

Trial

No.

Voltage V

Applied in

Volts

Theoretical Values Practical Values

Current

I in mili

amps

Current

I1

in mili

amps

Current

I2

in mili

amps

Current

I in mili

amps

Current

I1

in mili

amps

Current

I2

in mili

amps

1 0

2 5

3 10

4 15

5 20

6 25

7 30

V30V

R11.0kohm

R22.0kohm

0.045 A+ -

0.030 A+

- 0.015 A

+

-

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Calculations Here ↓:

Procedure:

1. Before doing the connection, check all the components and equipments.

2. Make the connection as shown in the circuit diagram.

3. Take two fixed value resistors R1 and R2.

4. Vary voltage applied from 0V to 30V in steps of 5V and record corresponding

values of currents I, I1 and I2 from corresponding ammeters.

5. Also calculate theoretical values of current using equations given above and

record in the data table.

6. Observe the difference between theoretical and practical values of currents.

Results:

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Experiment No. 3

Verification of Kirchhoff's Voltage law for D.C Circuits

Aim of the Experiment:

To verify Kirchhoff’s voltage law.

Equipments & Components Required:

1. Two fixed value resistors.

2. Regulated power supply.

3. Connecting wires.

4. Ammeter or Multimeter.

Theory:

Kirchhoff's second law, Kirchhoff's loop (or mesh) rule states that the algebraic sum

of the voltage (potential) differences in any loop must equal zero.

If we consider a closed loop, conventionally if we consider all the voltage gains along

the loop are positive then all the voltage drops along the loop should be considered as

negative. The summation of all these voltages in a closed loop is equal to zero.

Suppose n numbers of back to back connected elements form a closed loop. Among

these circuit element m number elements are voltage source and n – m number of elements

are resistors then,

The voltages of sources are V1, V2, V3,………………. Vm and voltage drops across the

resistors respectively, Vm + 1, Vm + 2, Vm + 3,………………… Vn.

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As it said that the voltage gain conventionally considered as positive, and voltage drops are considered as negative, the voltages along the closed loop are

+ V1, + V2, + V3,………………. + Vm, − Vm + 1, − Vm + 2, − Vm + 3,…………………− Vn.

Now according to Kirchhoff Voltage law the summation of all these voltages results to zero.

That means, V1 + V2 + V3 + …………. + Vm − Vm + 1 − Vm + 2 − Vm + 3 + ……………− Vn = 0

So accordingly Kirchhoff Second Law, ∑V = 0

Experiment:

Circuit Diagram:

Current and Voltage Equations:

Equivalent Resistance REQU = R1+R2

Total Current I = V/ REQU

Voltage across R1 is V1 = I * R1

Voltage across R2 is V2 = I * R2

V30V

R11.0kohm

R22.0kohm

0.010 A+ -

10.007 V+

-

19.993 V+

-

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Data Table:

Trial

No.

Voltage V

Applied in

Volts

Theoretical Values Practical Values

Current

I in mili

amps

Voltage

V1 in

Volts

Voltage

V2 in

Volts

Current

I in mili

amps

Voltage

V1 in

Volts

Voltage

V2 in

Volts

1 0

2 5

3 10

4 15

5 20

6 25

7 30

Calculations Here ↓:

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Procedure:

1. Before doing the connection, check all the components and equipments.

2. Make the connection as shown in the circuit diagram.

3. Take two fixed value resistors R1 and R2.

4. Vary voltage applied from 0V to 30V in steps of 5V and record corresponding

values of currents I, V1 and V2 from corresponding meters.

5. Also calculate theoretical values of current I, Voltages V1 and V2 using equations

given above and record in the data table.

6. Observe the difference between theoretical and practical values.

Results:

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Sanjay Memorial Polytechnic, Sagar

Characteristics of junction diode (Forward & Reverse Bias)

Aim of the Experiment:

To study characteristics of junction diode in both forward and reverse

Equipments & Components Required:

1. Resistors - 1K

2. Diode – BY127, 1N4001, …, 1N4007

3. Regulated power supply.

4. Connecting wires.

5. Ammeter and Multimeter.

Theory:

A diode is a two-terminal

low (ideally zero) resistance

resistance in the other.

A p–n junction diode is made of a crystal of

it to create a region on one side that contains negative

type semiconductor, and a region on the other side that contains positive charge carriers

(holes), called p-type semiconductor

attached together, a momentary flow of electrons occur from n to p side resulti

region where no charge carriers are present. It is called Depletion region due to the absence

of charge carriers (electrons and holes in this case). The diode's terminals are attached to

each of these regions. The boundary between these two r

where the action of the diode takes place. The crystal allows electrons to flow from the N

type side (called the cathode

direction.

The symbol used for a semiconductor diode in a

diode. There are alternate symbols for some types of diodes, though the differences are

minor.

Diode LED

Zener Diode Tunnel Diode

Sanjay Memorial Polytechnic, Sagar

Experiment No. 4

Characteristics of junction diode (Forward & Reverse Bias)

To study characteristics of junction diode in both forward and reverse

Equipments & Components Required:

1KΩ

BY127, 1N4001, …, 1N4007

Regulated power supply.

Connecting wires.

Multimeter.

terminal electronic component with asymmetric

resistance to current flow in one direction, and high (ideally

n junction diode is made of a crystal of semiconductor. Impurities are added to

it to create a region on one side that contains negative charge carriers

, and a region on the other side that contains positive charge carriers

type semiconductor. When two materials i.e. n-

attached together, a momentary flow of electrons occur from n to p side resulti

region where no charge carriers are present. It is called Depletion region due to the absence

of charge carriers (electrons and holes in this case). The diode's terminals are attached to

each of these regions. The boundary between these two regions, called a

where the action of the diode takes place. The crystal allows electrons to flow from the N

cathode) to the P-type side (called the anode), but not in the opposite

The symbol used for a semiconductor diode in a circuit diagram

diode. There are alternate symbols for some types of diodes, though the differences are

Photo Diode Schottky diode

Tunnel Diode Varicap

29

Characteristics of junction diode (Forward & Reverse Bias)

To study characteristics of junction diode in both forward and reverse bias condition.

with asymmetric conductance, it has

nt flow in one direction, and high (ideally infinite)

. Impurities are added to

charge carriers (electrons), called n-

, and a region on the other side that contains positive charge carriers

type and p-type are

attached together, a momentary flow of electrons occur from n to p side resulting in a third

region where no charge carriers are present. It is called Depletion region due to the absence

of charge carriers (electrons and holes in this case). The diode's terminals are attached to

egions, called a p–n junction, is

where the action of the diode takes place. The crystal allows electrons to flow from the N-

), but not in the opposite

circuit diagram specifies the type of

diode. There are alternate symbols for some types of diodes, though the differences are

Schottky diode

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Junction Diode Symbol and Static I-V Characteristics.

Forward Biased Junction Diode

When a diode is connected in a Forward Bias condition, a negative voltage is applied

to the N-type material and a positive voltage is applied to the P-type material. If this

external voltage becomes greater than the value of the potential barrier, approx. 0.7 volts

for silicon and 0.3 volts for germanium, the potential barriers opposition will be overcome

and current will start to flow.

This is because the negative voltage pushes or repels electrons towards the junction

giving them the energy to cross over and combine with the holes being pushed in the

opposite direction towards the junction by the positive voltage. This results in a

characteristics curve of zero current flowing up to this voltage point, called the "knee" on

the static curves and then a high current flow through the diode with little increase in the

external voltage as shown below.

Forward Characteristics Curve for a Junction Diode

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The application of a forward biasing voltage on the junction diode results in the

depletion layer becoming very thin and narrow which represents a low impedance path

through the junction thereby allowing high currents to flow. The point at which this sudden

increase in current takes place is represented on the static I-V characteristics curve above as

the "knee" point.

Forward Biased Junction Diode showing a Reduction in the Depletion Layer

This condition represents the low resistance path through the PN junction allowing

very large currents to flow through the diode with only a small increase in bias voltage. The

actual potential difference across the junction or diode is kept constant by the action of the

depletion layer at approximately 0.3v for germanium and approximately 0.7v for silicon

junction diodes.

Since the diode can conduct "infinite" current above this knee point as it effectively

becomes a short circuit, therefore resistors are used in series with the diode to limit its

current flow. Exceeding its maximum forward current specification causes the device to

dissipate more power in the form of heat than it was designed for resulting in a very quick

failure of the device.

Reverse Biased Junction Diode

When a diode is connected in a Reverse Bias condition, a positive voltage is applied

to the N-type material and a negative voltage is applied to the P-type material. The positive

voltage applied to the N-type material attracts electrons towards the positive electrode and

away from the junction, while the holes in the P-type end are also attracted away from the

junction towards the negative electrode.

The net result is that the depletion layer grows wider due to a lack of electrons and

holes and presents a high impedance path, almost an insulator. The result is that a high

potential barrier is created thus preventing current from flowing through the semiconductor

material.

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Reverse Biased Junction Diode showing an Increase in the Depletion Layer

This condition represents a high resistance value to the PN junction and practically

zero current flows through the junction diode with an increase in bias voltage. However, a

very small leakage current does flow through the junction which can be measured in

microamperes, (μA). One final point, if the reverse bias voltage Vr applied to the diode is

increased to a sufficiently high enough value, it will cause the PN junction to overheat and

fail due to the avalanche effect around the junction. This may cause the diode to become

shorted and will result in the flow of maximum circuit current, and this shown as a step

downward slope in the reverse static characteristics curve below.

Reverse Characteristics Curve for a Junction Diode

Sometimes this avalanche effect has practical applications in voltage stabilising

circuits where a series limiting resistor is used with the diode to limit this reverse

breakdown current to a preset maximum value thereby producing a fixed voltage output

across the diode. These types of diodes are commonly known as Zener Diodes and are

discussed in a later tutorial.

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Experiment:

Circuit Diagram:

Forward Biased Junction Diode

Data Table:

Trial

No.

Forward

Voltage Vd

In Volts

Forward

Current Id in

mili amps

1 0.1

2 0.2

3 0.3

4 0.4

5 0.5

6 0.6

7 0.7

8 0.8

9 0.9

10 1.0

V130V

R1

1.0kohm 0.029 A

+ -

0.668 V+

-

D11N4001GP

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Reverse Biased Junction Diode

Data Table:

Trial

No.

Reverse Voltage

Vr

In Volts

Reverse Current

Ir in micro amps

1 2

2 4

3 6

4 8

5 10

6 12

7 14

8 16

9 18

10 20

V130V

R1

1.0kohm 0.028m A

+ -

29.969 V+

-

D11N4001GP

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Procedure:

1. Before doing the connection, check all the components and equipments.

2. Make the connection as shown in the circuit diagram.

3. Vary the applied voltage in both forward and reverse bias as given in the data

table.

4. Record forward and reverse currents in both forward and reverse conditions.

5. Plot a graph for both forward and reverse bias conditions by taking voltage along

the X-axis and current along Y-axis

Results:

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Experiment No. 5

Characteristics of zener diode (Forward & Reverse Bias)

Aim of the Experiment:

To study characteristics of zener diode in both forward and reverse bias condition.

Equipments & Components Required:

1. Resistors - 1KΩ

2. Zener Diode

3. Regulated power supply.

4. Connecting wires.

5. Ammeter and Multimeter.

Theory:

A Zener diode is a diode which allows current to flow in the forward direction in the

same manner as an ideal diode, but will also permit it to flow in the reverse direction when

the voltage is above a certain value known as the breakdown voltage, "zener knee voltage",

"zener voltage" or "avalanche point".

A conventional solid-state diode will allow significant current if it is reverse-biased

above its reverse breakdown voltage. When the reverse bias breakdown voltage is

exceeded, a conventional diode is subject to high current due to avalanche breakdown.

Unless this current is limited by circuitry, the diode will be permanently damaged due to

overheating. A zener diode exhibits almost the same properties, except the device is

specially designed so as to have a reduced breakdown voltage, the so-called zener voltage.

By contrast with the conventional device, a reverse-biased zener diode will exhibit a

controlled breakdown and allow the current to keep the voltage across the zener diode

close to the zener breakdown voltage. For example, a diode with a zener breakdown voltage

of 3.2 V will exhibit a voltage drop of very nearly 3.2 V across a wide range of reverse

currents. The zener diode is therefore ideal for applications such as the generation of a

reference voltage (e.g. for an amplifier stage), or as a voltage stabilizer for low-current

applications.

Example: Circuit

symbol:

a = anode, k = cathode

Zener diodes are used to maintain a fixed voltage. They are

designed to 'breakdown' in a reliable and non-destructive

way so that they can be used in reverse to maintain a fixed

voltage across their terminals. The diagram shows how

they are connected, with a resistor in series to limit the

current.

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Zener diodes can be distinguished from ordinary diodes by their code and breakdown

voltage which are printed on them. Zener diode codes begin BZX... or BZY... Their

breakdown voltage is printed with V in place of a decimal point, so 4V7 means 4.7V for

example.

Zener diodes are rated by their breakdown voltage and maximum power:

• The minimum voltage available is 2.4V.

• Power ratings of 400mW and 1.3W are common.

Zener Diode Symbol and Static I-V Characteristics.

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Experiment:

Circuit Diagram:

Forward Biased Zener Diode

Data Table:

Trial

No.

Forward

Voltage Vd

In Volts

Forward

Current Id in

mili amps

1 0.1

2 0.2

3 0.3

4 0.4

5 0.5

6 0.6

7 0.7

8 0.8

9 0.9

10 1.0

V130V

R1

1.0kohm 0.029 A

+ -

0.627 V+

-

D1RD4.7

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Reverse Biased Zener Diode

Data Table:

Trial

No.

Reverse Voltage

Vr

In Volts

Reverse Current

Ir in micro amps

1 2

2 4

3 6

4 8

5 10

6 12

7 14

8 16

9 18

10 20

V110V

R1

1.0kohm 5.034m A

+ -

4.965 V+

-

D1RD4.7

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Procedure:

1. Before doing the connection, check all the components and equipments.

2. Make the connection as shown in the circuit diagram.

3. Vary the diode voltage in both forward and reverse bias as given in the data

table.

4. Record forward and reverse currents in both forward and reverse conditions.

5. Plot a graph for both forward and reverse bias conditions by taking voltage along

the X-axis and current along Y-axis

Results:

Page 41: Be lab-1st sem cse

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Sanjay Memorial Polytechnic, Sagar

Inverting amplifier using OP

Aim of the Experiment:

To study OP-AMP as an inverting amplifier

Equipments & Components Required:

1. Resistors - 1K

2. OP-AMP - µA741

3. Regulated power supply.

4. Signal Generator

5. Connecting wires.

6. CRO.

Theory:

An operational amplifier (op

amplifier with a differential input

an op-amp produces an output potential (relative to circuit ground) that is typically

hundreds of thousands of times larger than the potential difference between its input

terminals.

Circuit notation

Circuit diagram symbol for an

The circuit symbol for an op

• V+: non-inverting input

• V−: inverting input

• Vout: output

• VS+: positive power supply

• VS−: negative power supply

Sanjay Memorial Polytechnic, Sagar

Experiment No. 6

Inverting amplifier using OP-AMP

AMP as an inverting amplifier.

Equipments & Components Required:

1KΩ & 10KΩ

µA741

Regulated power supply.

Signal Generator

Connecting wires.

An operational amplifier (op-amp) is a DC-coupled high-gain

differential input and, usually, a single-ended output. In this

amp produces an output potential (relative to circuit ground) that is typically

hundreds of thousands of times larger than the potential difference between its input

Circuit diagram symbol for an op-amp

The circuit symbol for an op-amp is shown to the right, where:

inverting input

: inverting input

: output

: positive power supply

: negative power supply

41

gain electronic voltage

ended output. In this configuration,

amp produces an output potential (relative to circuit ground) that is typically

hundreds of thousands of times larger than the potential difference between its input

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Sanjay Memorial Polytechnic, Sagar

Operation

An op-amp without negative feedback (a comparator)

The amplifier's differential inputs consist of a

op-amp amplifies only the difference in voltage between the two, which is called the

differential input voltage. The output voltage of the op

Where V+ is the voltage at the non

inverting terminal and A

loop" refers to the absence of a feedback loop from the output to the input).

The magnitude of AOL is typically very large

op-amps—and therefore even a quite small difference between V+ and V

amplifier output nearly to the supply voltage. Situations in which the output voltage

is equal to or greater than the supply voltage are referred to as saturation of the

amplifier. The magnitude of AOL is not well controlled by the manufacturing process,

and so it is impractical to use an operational amplifier as a stand

amplifier. Without negative feedback

inverting input is held at ground (0 V) directly or by a resistor, and the input voltage

Vin applied to the non-

positive; if Vin is negative, the output will be maximum negative. Since there is no

feedback from the output to either input, this is an

comparator.

An op-amp with negative feedback (a non

amp without negative feedback (a comparator)

The amplifier's differential inputs consist of a V+ input and a V− input, and ideally the

amp amplifies only the difference in voltage between the two, which is called the

. The output voltage of the op-amp is given by the equa

is the voltage at the non-inverting terminal, V− is the voltage at the

AOL is the open-loop gain of the amplifier (the term "open

loop" refers to the absence of a feedback loop from the output to the input).

The magnitude of AOL is typically very large—100,000 or more for integrated circuit

and therefore even a quite small difference between V+ and V

amplifier output nearly to the supply voltage. Situations in which the output voltage

ual to or greater than the supply voltage are referred to as saturation of the

amplifier. The magnitude of AOL is not well controlled by the manufacturing process,

and so it is impractical to use an operational amplifier as a stand-alone

negative feedback, an op-amp acts as a comparator

inverting input is held at ground (0 V) directly or by a resistor, and the input voltage

-inverting input is positive, the output will be maximum

tive; if Vin is negative, the output will be maximum negative. Since there is no

feedback from the output to either input, this is an open loop circuit acti

amp with negative feedback (a non-inverting amplifier)

42

input, and ideally the

amp amplifies only the difference in voltage between the two, which is called the

amp is given by the equation:

is the voltage at the

gain of the amplifier (the term "open-

loop" refers to the absence of a feedback loop from the output to the input).

100,000 or more for integrated circuit

and therefore even a quite small difference between V+ and V− drives the

amplifier output nearly to the supply voltage. Situations in which the output voltage

ual to or greater than the supply voltage are referred to as saturation of the

amplifier. The magnitude of AOL is not well controlled by the manufacturing process,

alone differential

comparator. If the

inverting input is held at ground (0 V) directly or by a resistor, and the input voltage

inverting input is positive, the output will be maximum

tive; if Vin is negative, the output will be maximum negative. Since there is no

circuit acting as a

inverting amplifier)

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Sanjay Memorial Polytechnic, Sagar

If predictable operation is desired, negative feedback is used, by applying a portion

of the output voltage to the inverting input. The

reduces the gain of the amplifier. When negative feedback is used, the circuit's

overall gain and response becomes determined mostly by the feedback network

rather than by the op

For example, in a non

negative feedback via the voltage divider Rf, Rg reduces the gain. Equilibrium will be

established when Vout is just sufficient to reach around and "pull" the inverting

input to the same voltage as Vin. The voltage gain of the entire circuit is determined

by 1 + Rf/Rg. As a simple example, if Vin = 1V and Rf = Rg, Vout will be 2V, the

amount required to keep V

a closed loop circuit. Its overall gain Vout

Because the feedback is negative, in this case ACL is less than the AOL of the op

Another way of looking at it is to make two relatively valid assumptions.

One, that when an op

difference in voltage between the non

small as to be considered negligible.

The second assumption is that the input impedance at both (+) and

extremely high (at least several megohms with modern op

Thus, when the circuit to the right is operated as a non

will appear at the (+) and (

Sinc Kirchhoff's current law states that the same current must leave a node as enter

it, and since the impedance into the (

overwhelming majority of the same current i travels through Rf, creating an output

voltage equal to Vin + i × Rf. By combining terms, we can easily determine the gain of

this particular type of circuit.

Sanjay Memorial Polytechnic, Sagar

If predictable operation is desired, negative feedback is used, by applying a portion

ltage to the inverting input. The closed loop

reduces the gain of the amplifier. When negative feedback is used, the circuit's

overall gain and response becomes determined mostly by the feedback network

rather than by the op-amp itself.

For example, in a non-inverting amplifier (see the figure on the right) adding a

negative feedback via the voltage divider Rf, Rg reduces the gain. Equilibrium will be

established when Vout is just sufficient to reach around and "pull" the inverting

to the same voltage as Vin. The voltage gain of the entire circuit is determined

by 1 + Rf/Rg. As a simple example, if Vin = 1V and Rf = Rg, Vout will be 2V, the

amount required to keep V− at 1V. Because of the feedback provided by Rf, Rg this is

loop circuit. Its overall gain Vout / Vin is called the closed

Because the feedback is negative, in this case ACL is less than the AOL of the op

Another way of looking at it is to make two relatively valid assumptions.

n op-amp is being operated in linear (not saturated) mode, the

difference in voltage between the non-inverting (+) pin and the inverting (

as to be considered negligible.

The second assumption is that the input impedance at both (+) and

extremely high (at least several megohms with modern op

Thus, when the circuit to the right is operated as a non-inverting linear amplifier, Vin

will appear at the (+) and (−) pins and create a current i through Rg equal to Vin/Rg.

Kirchhoff's current law states that the same current must leave a node as enter

it, and since the impedance into the (−) pin is near infinity, we can assume the

overwhelming majority of the same current i travels through Rf, creating an output

l to Vin + i × Rf. By combining terms, we can easily determine the gain of

this particular type of circuit.

43

If predictable operation is desired, negative feedback is used, by applying a portion

closed loop feedback greatly

reduces the gain of the amplifier. When negative feedback is used, the circuit's

overall gain and response becomes determined mostly by the feedback network

inverting amplifier (see the figure on the right) adding a

negative feedback via the voltage divider Rf, Rg reduces the gain. Equilibrium will be

established when Vout is just sufficient to reach around and "pull" the inverting

to the same voltage as Vin. The voltage gain of the entire circuit is determined

by 1 + Rf/Rg. As a simple example, if Vin = 1V and Rf = Rg, Vout will be 2V, the

− at 1V. Because of the feedback provided by Rf, Rg this is

Vin is called the closed-loop gain ACL.

Because the feedback is negative, in this case ACL is less than the AOL of the op-amp.

Another way of looking at it is to make two relatively valid assumptions.

amp is being operated in linear (not saturated) mode, the

e inverting (−) pin is so

The second assumption is that the input impedance at both (+) and (−) pins is

extremely high (at least several megohms with modern op-amps).

inverting linear amplifier, Vin

−) pins and create a current i through Rg equal to Vin/Rg.

Kirchhoff's current law states that the same current must leave a node as enter

−) pin is near infinity, we can assume the

overwhelming majority of the same current i travels through Rf, creating an output

l to Vin + i × Rf. By combining terms, we can easily determine the gain of

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Sanjay Memorial Polytechnic, Sagar

Op-amp characteristics

Ideal op-amps

An ideal op-amp is usually considered to have the following properties:

• Infinite open

• Infinite voltage range available at the output

• Infinite bandwidth with zero phase shift and infinite slew rate

• Infinite input impedance and so zero input current and zero input

offset voltage

• Zero output impedance

• Zero noise

• Infinite Common

• Infinite Power supply rejection ratio.

These ideals can be summarized by the two "golden rules":

I. The output attempts to do whatever is necessary to make the

voltage difference between the inputs zero.

II. The inputs draw no current

Pin Diagram of µA741 Op

amp is usually considered to have the following properties:

Infinite open-loop gain.

Infinite voltage range available at the output.

Infinite bandwidth with zero phase shift and infinite slew rate

Infinite input impedance and so zero input current and zero input

offset voltage.

Zero output impedance.

Zero noise.

Infinite Common-mode rejection ratio (CMRR).

Infinite Power supply rejection ratio.

These ideals can be summarized by the two "golden rules":

I. The output attempts to do whatever is necessary to make the

voltage difference between the inputs zero.

II. The inputs draw no current.

Pin Diagram of µA741 Op-Amp

44

amp is usually considered to have the following properties:

Infinite bandwidth with zero phase shift and infinite slew rate.

Infinite input impedance and so zero input current and zero input

I. The output attempts to do whatever is necessary to make the

Page 45: Be lab-1st sem cse

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Basic Electronics Lab Manual

Sanjay Memorial Polytechnic, Sagar

Experiment:

Circuit Diagram:

Procedure:

1. Connect the circuit as shown in the circuit diagram.

2. Give the input signal as specified.

3. Switch on the power supply.

4. Note down the outputs from the CRO

5. Draw the necessary waveforms on the graph sheet.

Observations:

1. Observe the output waveform from CRO. An inverted and amplified waveform will be

observed.

2. Measure the input and output voltage from the input and output waveform in the CRO.

3. Calculate

4. Compare the theoretical voltage gain from the above equation with the experimental

value obtained by dividing output voltage by input voltages observed.

5. Observe outputs of the inverting amplifier circuit using different input waveforms.

Results:

Pin 7 → +12V

Pin 4 → -12V

R1 = 1KΩ

R2 = 10KΩ

Gain = -R2/R1

Page 46: Be lab-1st sem cse

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Basic Electronics Lab Manual

Sanjay Memorial Polytechnic, Sagar

Experiment No. 7

Non-inverting amplifier using OP-AMP

Aim of the Experiment:

To study OP-AMP as non-inverting amplifier.

Equipments & Components Required:

1. Resistors - 1KΩ & 10KΩ

2. OP-AMP - µA741

3. Regulated power supply.

4. Signal Generator

5. Connecting wires.

6. CRO.

Theory:

Same as Experiment no. 6.

Experiment:

Circuit Diagram:

Procedure:

1. Connect the circuit as shown in the circuit diagram.

2. Give the input signal as specified.

3. Switch on the power supply.

4. Note down the outputs from the CRO

5. Draw the necessary waveforms on the graph sheet.

Pin 7 → +12V

Pin 4 → -12V

R1 = 1KΩ

R2 = 10KΩ

Gain = 1+ (R2/R1)

Page 47: Be lab-1st sem cse

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Sanjay Memorial Polytechnic, Sagar

Observations:

1. Observe the output waveform from CRO. A non-inverted and amplified waveform will

be observed.

2. Measure the input and output voltage from the input and output waveform in the CRO.

3. Calculate

4. Compare the theoretical voltage gain from the above equation with the experimental

value obtained by dividing output voltage by input voltages observed.

5. Observe outputs of the inverting amplifier circuit using different input waveforms.

Results:

Page 48: Be lab-1st sem cse

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Basic Electronics Lab Manual

Sanjay Memorial Polytechnic, Sagar

Experiment No. 8

Half wave rectifier - construction, calculation of ripple factor with and

without shunt capacitor filter.

Aim of the Experiment:

To construct and calculate half wave rectifier with and without filter.

Equipments & Components Required:

1. Resistors - 1KΩ

2. Step down transformer

3. Rectifier diode – BY 127, 1N4001… 4007.

4. Connecting wires.

5. CRO.

Theory:

Rectification is a process of converting ac to pulsating dc. Half wave rectifier convert

ac to pulsating dc by simply allowing half of the input ac cycle to pass, while blocking current

to prevent it from flowing during the other half cycle as shown below

While the output of a rectifier is a pulsating dc that means it contains both ripples

and dc components. Ripples are high frequency ac signals in the dc output of the rectifier.

Most electronic circuits require a substantially pure dc for proper operation. This type of

output is provided by single or multi-section filter circuits placed between the output of the

rectifier and the load.

Shunt Capacitor Filter

This is the simplest form of the filter circuit and in this arrangement a high value

capacitor C is placed directly across the output terminals, as shown in figure. During the

conduction period capacitor gets charged and during non-conduction period it discharges.

The time duration taken by capacitor C to get charged to peak value is negligible because

there is no resistance (except the negligible forward resistance of diode) in the charging

path. But the discharging time is quite large (roughly 100 times more than the charging time

depending upon the value of RL) because it discharges through load resistance RL.

Page 49: Be lab-1st sem cse

Basic Electronics Lab Manual

Sanjay Memorial Polytechnic, Sagar

Experiment:

Circuit Diagram:

Half wave rectifier without filter

Sanjay Memorial Polytechnic, Sagar

Half wave rectifier without filter

49

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Basic Electronics Lab Manual

Sanjay Memorial Polytechnic, Sagar

ac voltage at o/p

Ripple Factor =

dc voltage at o/p

Procedure:

1. Connect the primary side of the transformer to AC main as shown in the figure

2. Connect the C.R.O. probes to the output points. By proper setting of C.R.O.

stable wave shape can be seen on its screen .Plot this wave form &

wave shape at the o\p points.

3. Using multimeter measure AC and DC voltages at o/p points

4. Using the measured value of DC & AC output voltages, calculate Ripple factor .It should

be near about 1.21

Results:

Ripple Factor =

Circuit Diagram:

Half wave rectifier with filter

Procedure:

1. Connect the primary side of the transformer to AC main as shown in the figure

2. Connect the C.R.O. probes to the output points. By proper setting

stable wave shape can be seen on its screen .Plot this wave form & also observe the

wave shape at the o\p points. .

3. Using multimeter measure AC and DC voltages at o/p points

4. Using the measured value of DC & AC output volta

ac voltage at o/p

= 1.21 (Theoretical)

dc voltage at o/p

primary side of the transformer to AC main as shown in the figure

Connect the C.R.O. probes to the output points. By proper setting of C.R.O.

table wave shape can be seen on its screen .Plot this wave form & also observe the

p points. .

Using multimeter measure AC and DC voltages at o/p points.

Using the measured value of DC & AC output voltages, calculate Ripple factor .It should

Half wave rectifier with filter

primary side of the transformer to AC main as shown in the figure

Connect the C.R.O. probes to the output points. By proper setting of C.R.O.

table wave shape can be seen on its screen .Plot this wave form & also observe the

p points. .

Using multimeter measure AC and DC voltages at o/p points.

Using the measured value of DC & AC output voltages, calculate Ripple factor.

50

primary side of the transformer to AC main as shown in the figure.

Connect the C.R.O. probes to the output points. By proper setting of C.R.O. a good &

also observe the

Using the measured value of DC & AC output voltages, calculate Ripple factor .It should

primary side of the transformer to AC main as shown in the figure.

of C.R.O. a good &

table wave shape can be seen on its screen .Plot this wave form & also observe the

Ripple factor.

Page 51: Be lab-1st sem cse

Basic Electronics Lab Manual

Sanjay Memorial Polytechnic, Sagar

Full wave bridge rectifier

Aim of the Experiment:

To construct and calculate full wave

Equipments & Components Required:

1. Resistors - 1K

2. Step down transformer

3. Rectifier diode –

4. Connecting wires.

5. CRO.

Theory:

Rectification is a process of converting ac to pulsating dc

ac to pulsating dc by simply allow

to prevent it from flowing during the other half cycle as shown below

Sanjay Memorial Polytechnic, Sagar

Experiment No. 9

rectifier - construction, calculation of ripple factor with and

without shunt capacitor filter.

To construct and calculate full wave bridge rectifier with and without filter.

Equipments & Components Required:

1KΩ

Step down transformer

– BY 127, 1N4001… 4007.

Connecting wires.

Rectification is a process of converting ac to pulsating dc. Half wave rectifier

simply allowing half of the input ac cycle to pass, while blocking current

ing during the other half cycle as shown below

51

construction, calculation of ripple factor with and

without filter.

Half wave rectifier convert

ac cycle to pass, while blocking current

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When the upper end of the transformer secondary winding is positive, say during

first half-cycles of the input supply, diodes D1 and D3 are forward biased and current flows

through arm AB, enters the load at positive terminal, leaves the load at negative terminal,

and returns back flowing through arm DC. During this half of each input cycle, the diodes D2

and D4 are reverse biased and so the current is not allowed to flow in arms AD and BC. The

flow of current is indicated by solid arrows in the figure. In the second half of the input cycle

the lower end of ac supply becomes positive, diodes D2 and D4 become forward biased and

current flows through arm CB, enters the load at the positive terminal, leaves the load at

negative terminal and returns back flowing through arm DA. Flow of current has been

shown by dotted arrows in the figure. Thus the direction of flow of current through the load

resistance RL remains the same during both half cycles of the input supply voltage

Experiment:

Circuit Diagram:

Full wave bridge rectifier without filter

/

/ 0.482 (Theoretical)

Procedure:

1. Connect the primary side of the transformer to AC main as shown in the figure.

2. Connect the C.R.O. probes to the output points. By proper setting of C.R.O. a good &

stable wave shape can be seen on its screen .Plot this wave form & also observe the

wave shape at the o\p points. .

3. Using multimeter measure AC and DC voltages at o/p points.

4. Using the measured value of DC & AC output voltages, calculate Ripple factor .It should

be near about 1.21

Results:

Ripple Factor =

T1

TS_AUDIO_VIRTUAL

1

2

4

3

D1

1B4B42

R110kohm

V230V 50Hz 0Deg

Page 53: Be lab-1st sem cse

Basic Electronics Lab Manual

Sanjay Memorial Polytechnic, Sagar

Circuit Diagram:

Full wave bridge rectifier

Procedure:

1. Connect the primary side of the transformer to AC main as shown in the figure

2. Connect the C.R.O. probes to the output points. By proper setting of C.R.O.

stable wave shape can be seen on its

wave shape at the o\p points. .

3. Using multimeter measure AC and DC voltages at o/p points

4. Using the measured value of DC & AC output voltages, calculate

Sanjay Memorial Polytechnic, Sagar

rectifier with filter

primary side of the transformer to AC main as shown in the figure

Connect the C.R.O. probes to the output points. By proper setting of C.R.O.

table wave shape can be seen on its screen .Plot this wave form & also observe the

p points. .

Using multimeter measure AC and DC voltages at o/p points.

Using the measured value of DC & AC output voltages, calculate Ripple factor.

53

primary side of the transformer to AC main as shown in the figure.

Connect the C.R.O. probes to the output points. By proper setting of C.R.O. a good &

screen .Plot this wave form & also observe the

Ripple factor.