Multivibrator circuit, primarily utilizing the versatile IC 555 timer. Often referred to as a free-running oscillator, the astable multivibrator is unique because it possesses no stable equilibrium state; instead, it continuously oscillates between "High" and "Low" output levels without any external triggering. The core of the circuit's operation relies on a timing network composed of two resistors and a charging capacitor ). As the capacitor charges through both resistors toward of the supply voltage and discharges through toward of the supply voltage, the IC 555 toggles its output state. This cyclic process generates a continuous square wave pulse at the output pin, the frequency of which is precisely determined by the formula.Beyond basic wave generation, this project serves as a foundational study in timing and pulse synchronization, which are critical components in digital electronics. By adjusting the component values, the circuit was tuned to produce a visible flashing effect through an LED, demonstrating the practical application of the Duty Cycle. This circuit architecture is widely implemented in real-world systems, ranging from simple LED flashers and pulse-width modulation (PWM) controllers to clock signal generators for microprocessors and security alarm sirens. Successfully building this project provided hands-on experience in breadboard prototyping, understanding electronic data sheets, and analyzing the relationship between passive component values and signal frequency in analog-to-digital conversion systems

1. A P R O J E C T T O
D E S I G N A N
A S T A B L E
M U L T I V I B R A T O R
Analog Electronics
Students:
Montaser Alfadil
Francis Simon
Thomas Blackie
Doka Atif
Job Kaa
Under Supervision by:
Dr. M. L. Dewal

2. OUTLINE
• MOTIVATION
• CIRCUIT DIAGRAM
• COMPONENTS USED
• PROCEDURE
• APPLICATIONS

3. • Multivibrators are
switching circuits used in
digital systems for
timing, storage, and
synchronization.
What is Multivibrator?
MOTIVATION

4. TYPES OF MULTIVIBRATORS
The multivibrators are classified into three categories:
1. Astable Multivibrator. (Our Project)
2. Monostable Multivibrator.
3. Bistable Multivibrator.

5. ASTABLE MULTIVIBRATOR
• An astable multivibrator, also
called a free-running
multivibrator, is a circuit that
continuously produces square
waves or pulses without the use
of an external trigger. The term
"astable" refers to the absence
of a stable state in this
particular type of
multivibrator.

6. CIRCUIT DIAGRAM

7. COMPONENTS USED

8. PROCEDURE
1. Place Transistors: Mount the two transistors on the
breadboard, connecting their emitters to ground.
2. Add Resistors and LEDs: Attach resistors from the
power rail to each transistor's collector, with an
LED also running from the collector to ground.
3. Cross-Couple with Capacitors: Connect a resistor
from the power rail to each base, then use the 10µF
capacitors to link each collector to the opposite
base.
4. Power On: Supply power to the circuit to see the
LEDs begin to blink.

9. APPLICATIONS
Timing Circuits:
To generate the clock pulses that
synchronize a variety of digital
systems, from simple electronic
games to more complex computer
circuits and digital clocks.

10. APPLICATIONS
LED Flashing Circuits:
The most common and visible
application is in blinking or flashing
lights. The continuous on-and-off
pulse of the astable multivibrator
makes it perfect for applications like
indicator lights, turn signals, and
decorative lighting.

11. APPLICATIONS
Pulse Generators:
In electronics labs and test
equipment, an astable multivibrator
can serve as a simple pulse generator
to test other circuits. By adjusting
the resistor and capacitor values,
engineers can change the frequency
and duty cycle of the output pulse.

12. APPLICATIONS
Sound Generation:
The astable multivibrator can create
audible tones when its output is
connected to a speaker. This is used
in simple buzzers, alarms, and early
electronic musical instruments

13. SLIDE TITE
THE END
THANK YOU FOR LISTENING