I. About Project
III. Required Components
IV. Description on component
V. Circuit Diagram & Pin Diagram
VI. About Methodology
VII. Application / uses this Circuit
VIII. Work Plan
The 555 Timer IC is one of the most popular and
most frequently used integrated circuits. It performs
an array of timing tasks in the electronic circuits. But
before using the 555 Timer IC, check it’s whether, it
is working properly or not.
So, we are design a simple circuit that can be used
as a 555 Timer IC Testing Circuit and determine
whether the 555 IC is functioning or not.
Our objective is very clear, We are making a basic circuit with
help the of (active and passive ) components/elements which
help the testing 555 timer IC.
555 Timer IC is that it has three modes of operation: Astable,
Monostable and Bistable. The circuit implemented in this
project is basically an Astable Mode of operation of the 555
2 X 10KΩ Resistors
2 X 1KΩ Resistors
47μF Capacitor (Electrolytic)
0.01μF Capacitor (Ceramic Disc)
2 X LEDs
12V Power Supply
We are using
and 2*10Ω, 1KΩ
using for ‘LED’
and 10KΩ using
We are using
We are using
two LED light for
We should 5V to
12V power for our
circuit, So we can
use 9V power
Ex: - Battery,
555 Timer IC is main element/ component of
It have 8-PIN, Dual-in-line Package (DIP).
The 555 timer can be operated at a wide range
of power supplies ranging from 5 V to 18 V.
Ground reference voltage (low level
0V). All the voltages are measured
with respect to this terminal.
It is responsible for SET and RESET
transitions of the flip-flop.
Output driven waveform is available
at this pin. It is driven to 1.7 V below
VCC. Two types of loads can be
connected to the output.
A negative pulse on this pin will disable
or reset the timer. The timer will begin
only when the voltage on this pin is
above 0.7 V and hence it is normally
connected to VCC when not used.
It controls the threshold and trigger
levels and hence the timing of the
555. The width of the output pulse is
determined by the control voltage.
The voltage applied at this terminal is
compared with a reference voltage of
2/3 VCC. When the voltage at this
terminal is greater than 2/3 VCC, the
flip-flop is RESET and the output falls
from High to Low.
It is connected to the open collector of the
internal NPN transistor which discharges
the timing capacitor. When the voltage at
this pin reaches 2/3 VCC, the output
toggles from high to low.
A supply voltage in the range of 5V
to 18V is applied to this terminal.
In this circuit, We have used the 555 IC as an Astable multivibrator and when
power is provided to circuit, the LEDs will start blinking, which means that the IC
is working. The blinking rate of LEDs can be changed by increasing or
decreasing the values of resistor R1 and R2 and capacitor C1.
ON Time (HIGH) in Seconds = 0.693 * (R1
+ R2) * C1
OFF Time (LOW) in Seconds = 0.693 * R2 *
Total Time Period in Seconds = 0.693 * (R1
Frequency = 1.44 / ((R1 + 2R2) * C1)
Accordingour circuit(Resistors,Capacitorsand Power
Frequency = 1.023 Hertz
ON Time = 0.651 Seconds
OFF Time = 0.326 Seconds
Time Period = 0.977 Seconds
1 0 2021-22
Now to see the result, switch on the
power supply. If our 555 Timer IC is
working properly, then both the
LEDs (Red LEDs in my case) will
If any of the LED is OFF or both the
LEDs are not glowing, it means that
our 555 timer IC is faulty.
We will receive two different
1 1 2021-22
Square Wave Generation
Pulse Position Modulation
Frequency Modulation using Astable Multivibrator
Note: - our 555 testing IC circuit is used in this application
1 2 2021-22
S. NO. PARTICUAL DURATION OUTCOME
Study about the 555 Timer IC
2 Components Identification 26-Sep-2021
Identify Components to be
required in project
Layout Plane/ Circuit
Design of layout of electronics
4 Assembler Components 05-Oct-2021
Purchase Components form
5 Progress Presentation-1 11-Oct-2021
Represent project details in ppt