IC 555 AND IC741 TESTER

A lab-based Project report submitted to

VELAGAPUDI RAMAKRISHNA
SIDDHARTHA ENGINEERING COLLEGE
In partial fulfilment of the Requirements for the award of the Degree of
BACHELOR OF TECHNOLOGY
in
ELECTRICAL AND ELECTRONICS ENGINEERING

by

B.Avinash (218W5A0201)
Ch.Mohiddin Khan(218W5A0202)
Ch.Vinay Kumar (218W5A0203)
K.Blessy Babu (208W1A0227)
N.Naga Babu (208W1A0236)

Under the esteemed Guidance of

DR.G.KISHORE KUMAR SIR (Assistant Professor)

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

V.R. SIDDHARTHA ENGINEERING COLLEGE
(Autonomous)
(AFFILIATED TO JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITYKAKINADA)
APPROVED BY AICTE- ACCREDITED BY NBA
VIJAYAWADA-520007
2022
 ACKNOWLEDGEMENT

It gives me great pleasure to thank DR.G.KISHORE KUMAR SIR (Assistant Professor) in

Department of Electronics and Communication Engineering, for the constant support and guidance given to us
throughout the course of this project. We also take the opportunity to acknowledge the contribution of Dr.
P.V.R.L. Narasimham Sir (Head of The Department, Electrical and Electronics Engineering) and Dr.A.
RATNA PRASAD SIR (Principal) for his support and assistance during the development of the project. We
also take this the opportunity to acknowledge the contribution of all faculty members of the department for their
assistance and cooperation during the development of our project. We also thank all the Non-Teaching Staff of
the Department who helped us in the course of the project. Last but not the least, we acknowledge our friends
for their encouragement in the completion of the project.

B. Avinash (218W5A0201)
Ch. Mohiddin Khan(218W5A0202)
Ch. Vinay Kumar (218W5A0203)
K.Blessy Babu (208W1A0227)
N.Naga Babu (208W1A0236)
 DECLARATION
We hereby declare that the works is being presented in this lab-based project “ IC 555 AND IC 741
TESTER” submitted towards the partial fulfilment of requirements for the award of the degree of Bachelor of
Technology in Electrical and Electronics Engineering in VR Siddhartha Engineering College, is authentic record of
our work carried out under the supervision of DR.G.KISHORE KUMAR SIR (Assistant Professor) in ECE
department, VR Siddhartha Engineering College Vijayawada .The mater embodied in this report has not been
submitted by us for the award of any other degree.

B. Avinash Ch. Mohiddin Ch. Vinay Kumar

Khan
(218W5A0201) (218W5A0202) (218W5A0203)

K.Blessy Babu
(208W1A0227)

N.Naga Babu

(208W1A0236)
 CERTIFICATE

This is to certify that the Project report entitled “IC 555 AND IC741 TESTER” that is being submitted by
B.Avinash(218W5A0201),K.BlessyBabu(208W1A0227),Ch.MohiddinKhan(218W5A0202),Ch.Vinay
Kumar(218W5A0203), and N.Naga Babu(208W1A0236) in partial fulfilment for the award of the Degree of
Bachelor of Technology in Electrical and Electronics Engineering to the VR Siddhartha Engineering College
affiliated to JNTUK, Kakinada is a record of bona fide work carried out during the AY 2021-22.

Dr.G. Kishore Kumar Dr. P.V.R.L. Narasimham

(Assistant Professor, ECE) (Head Of the Department, EEE)

 INTRODUCTION

IC 555 And IC741 Tester

Sometimes we do not get proper output from a circuit due to faulty ICs. This circuit can test timer 555 and op-amp
741 ICs, which are commonly used in electronics practical laboratories, and project works. To save you from this
problem, we came up with an idea with low cost that could be helpful for all to check or test IC 555 and IC 741
whether it is working or not. This gives confirm message regarding the working of IC 555 and IC 741.
 WORKING
555 Timer as Astable Multivibrator

An astable multivibrator, often called a free-running multivibrator, is a rectangular-wave generating circuit.

Unlike the monostable multivibrator, this circuit does not require any external trigger to change the state of the
output, hence the name free-running.

Description
Pin 1 is grounded; pins 4 and 8 are shorted and then tied to supply +Vcc, output (Vout is taken form pin 3; pin 2
and 6 are shorted and the connected to ground through capacitor C, pin 7 is connected to supply + Vac through a
resistor Ra; and between pin 6 and 7 a resistor RB is connected. At pin 5 either a bypass capacitor of 0.01 F is
connected or modulation input is applied.

Initially, when the output is high, capacitor C starts charging towards Vcc through Ra and Rb. The time during
which the capacitor C charges from 1/3 Vcc to 2/3 Vcc is equal to the time the output is high and is given as
Tc/Thigh = 0.693 (RA + RB) C In our circuit where, Ra=10kohm Rb=100Kohm C=4.7uf
TC=0.69(10+100)10^3*4.7*10^-6 =0.3567s. The time during which the capacitor discharges from +2/3 V cc to
+1/3 Vcc is equal to the time the output is low and is given as Td/T low = 0.693 RbC.
This circuit can test timer 555 AND we got led proper output from a circuit. LED1 glows when pin 3 is high, LED2
glows when pin 3 is low. This indicates that the 555 timer under test is in good condition.
 IC 741 TESTER

The op-amp IC 741 is a DC-coupled, high gain differential amplifier with external negative feedback. IC 741 is
characterized by the almost infinite open-loop gain (100,000), almost infinite input impedance (2MΩ), and almost zero
output impedance (75Ω). IC 741 is the most popular, cheap, and easy-to-use op-amp. Various type of circuit is designed
using Op-amp 741 out of which some are voltage follower, current to voltage converter and vice versa, summing
amplifier, etc.

Circuit Description of IC 741 Tester

The circuit of the operational amplifier 741 tester comprises two diode and very few passive components and a 741 IC
to be tested. All the components are connected as shown in the circuit diagram. An LED1 is used to indicate whether
IC is good or fault. Blinking LED1 indicates IC is good.

Working of the circuit | IC 741 Tester

The working of the circuit is simple. The IC to be tested is configured in voltage comparator mode. The voltage
at pin 3 (noninverting pin) is fixed whereas the voltage at pin 2 (inverting pin) varies due to the charging and
discharging of capacitor C1. Where the battery is connected to the circuit the voltage at pin 3 is high compared to
the voltage at pin 2 due to the charging of the capacitor, as a result, the output of IC becomes high, and the LED
starts to glow.

At this instant capacitor start to charge through the resistor R4. When the charge (voltage) of the capacitor
exceeds the voltage at inverting pin (pin 2), the output of IC becomes LOW, as a result, the LED stops glowing.
When the voltage at the capacitor becomes higher than inverting input pin it starts to discharge and again the
output of IC becomes high. This high and low output of IC generates a square wave and causes LEDs to blink.
CIRCUIT DIAGRAM

Fig.1.1 IC741 tester

Fig.1.2 555IC tester

COMPONENTS REQUIRED:
 Timer IC (IC 555)
 Op-Amp (IC741)
 LED
 Resistors
 Capacitor
 Diode(IN4007)
 9V Battery
 Connecting Wires
 Breadboard
 COMPONENT DESCRIPTION

LED (Light Emitting Diode):

Light-emitting diodes are heavily doped p-n junctions. Based on the semiconductor
materialused and the amount of doping, an LED will emit a coloured light at a particular
spectral wavelength whenforward biased. An LED is encapsulated with a transparent cover
so that emitted light can come out.

The energy is released in the form of

photons on recombination. In standard diodes, the
energy is released in the form of heat. But in light-
emitting diodes, the energy is released in the form of
photons. We call this phenomenon electroluminescence.
Electroluminescence is an optical phenomenon, and electrical phenomenon where a material
emits light in response to an electric current passed through it. As the forward voltage
increases, the intensity of the light increases and reaches a maximum.

semiconductor layer (which acts as the control electrode)

produces a large, rapid change in the current passing through

RESISTOR:

A resistor is a passive two-terminal electrical

component that implements electrical resistance as a circuit
element. In electronic circuits, resistorsare used to reduce current
flow, adjust signal levels, to divide voltages, bias active elements,
and terminate transmission lines, among other uses.

Fixed resistors have resistances that only change slightly with temperature, time or
operating voltage. Variable resistors can be used to adjust circuit elements (such as a
volume control or alamp dimmer), or as sensing devices for heat, light, humidity, force, or
chemical activity.
CAPACITOR:

A capacitor is a device that stores electrical

energy in an electric field. It is a passive electronic component
with two terminals. The effect of a capacitor is known as
capacitance.
While some capacitance exists between any two electrical conductors in proximity in a
circuit, a capacitor is a component designed to add capacitance to a circuit. The capacitor
was originally known as a condenser.

BATTERY:
An electric battery is a source of
electric power consisting of one or more electrochemical
cells with external connections for powering electrical
devices. When a battery is supplying power, its positive
terminal is the cathode and its negative terminal is the
anode. The terminal marked negative is the source of
electrons that will flow through an external electric
circuit to the positive terminal.

CONNECTING WIRES:

With that, we have to connect wires to the posts

in order to connect them to the breadboard. To do that, unscrew
the post until the hole going through it is exposed. Slide the
stripped end of your jumper wire throughthe hole, and screw the
post back down until the wire is firmly connected.

BREADBOARD:

A breadboard, or protoboard, is a
construction base for prototyping of electronics.
Originally the word referred to a literal bread
board, a polished piece of wood used when slicing
bread.
DIODE (IN4007)
A p–n diode is a type of semiconductor diode based
upon the p–n junction. The diode conducts current in
only one direction, and it is made by joining a p-type
semiconducting layer to an n-type semiconducting
layer. Semiconductor diodes have multiple uses
including rectification of alternating current to direct
current, in the detection of radio signals, emitting light
and detecting light.

IC555 TIMER:

The 555 timer IC is an integral part of

electronics projects. Be it a simple project involving a
single 8-bit micro-controller and some peripherals or a
complex one involving system on chips (SoCs), 555
timer working is involved. These provide time delays, as
an oscillator and as a flip-flop element among other
applications.

IC 741:

The 741 IC op-amp looks like a chip and

it is a general purpose op amp. The 741IC op amp
diagram is shown below that consists of 8 pins. The
most important pins are pin-2, pin-3 and pin-6 because
pin 2 and 3 represent inverting and non-inverting
terminals where pin6 represents voltage out. The
triangular diagram in the op-amp represents an Op-
Amp integrated circuit. The modern version of the IC is
represented by the famous 741 op-amp. Op-amp is
mainly used to perform mathematical operations in
various electronic circuits.
MODEL CIRCUIT
RESULTS
 ADVANTAGES
 These are easy to install and test IC’s

 Circuit is simple
 Cost is low

APPLICATIONS
 In Laboratories to check the IC condition before conducting the experiment.

 Industrial Instrumentation

CONCLUSION
We came with an idea with the low cost that could be helpful for all to check or test
IC555 and IC 741 whether it is working or not.

REFERENCES
 https://www.electronicshub.org

 http://en.wikioedia.org/wiki/Main-page
