Friday, October 22, 2021

Definition and Types of Multivibrator

Definition and Types of Multivibrator - The multivibrator is an electronic device or circuit that produces non-sinusoidal waves such as square waves, rectangular waves, and saw waves. These multivibrators are commonly used in frequency generators, frequency dividers, time delay generators, and memory elements in computers, and so on.

Basically, a Multivibrator is a two-stage resistance-capacitance (RC) coupled amplifier with positive feedback from the output of one amplifier to the input of the other. The output of the first amplifier acts as an input for the second amplifier, then the output of the second amplifier will enter as the first input through the feedback path that has been provided.

Types of Multivibrators

Types of Multivibrators

There are two possible conditions on the Multivibrator, the first is ON in the first amplifier and OFF in the second amplifier, while the second condition is OFF in the first amplifier and ON in the second amplifier. These two conditions alternate for a certain period depending on the state of the circuit. Based on the method of alternating these two conditions, Multivibrators can be classified into 3 types, namely Astable Multivibrators, Monostable Multivibrators, and Bistable Multivibrators.

1. Monostable Multivibrator

Monostable Multivibrator is a Multivibrator that has a stable state as well as a quasi-stable state. Monostable multivibrators have a trigger input to a single amplifying transistor. So, one transistor changes its state automatically, while the other requires a trigger input to change its state.

Since this multivibrator produces one output for each trigger pulse, it is also known as a one-shot multivibrator. This multivibrator cannot stay in a quasi-stable state for much longer, but it can remain in a stable state until a trigger pulse is received.

Monostable multivibrators are widely used in analog systems to control the signal frequency at the Output and are also used to regenerate the Distorted Pulsed Signal.

Related Articles : Definition of Monostable Multivibrator and How It Works

2. Astable Multivibrator

An Astable Multivibrator is a circuit that automatically switches between two states/conditions continuously without any external pulse as a trigger for its operation. This Astable Multivibrator is also often referred to as a Free Running Multivibrator because this type of multivibrator produces a continuous square wave output or changes state/condition by itself after some predetermined time interval.

The time interval or the time period for the ON and OFF conditions on the Multivibrator depends on the time constant of the components used. A multivibrator that keeps alternating this state is known as a quasi-stable state. Thus, the Astable Multivibrator does not have a stable state which alternates continuously between two states/conditions in producing a pulse wave at a fixed frequency.

In its application, Astable Multivibrators can usually be found in delay and timing circuits as well as in transmitting and receiving radio signals.

Related Articles : Definition of Astable Multivibrator and How It Works

3. Bistable Multivibrator

Bistable Multivibrator is a type of Multivibrator having two stable conditions. This type of multivibrator requires two trigger pulses to change its state or state. This multivibrator cannot change its state if it does not receive input from the trigger. This Bistable Multivibrator is also known as a flip-flop Multivibrator.

When given a trigger pulse, the transistor amplifier in the circuit will be disconnected thus indicating a stable state. However, when another trigger pulse is given, the transistor starts conduction again. Thus changing its state from one state to another.

Bistable Multivibrators are used as Frequency Dividers, Counters, Latches, and Memory Storage Units.

So, we can conclude that the multivibrator is a circuit that can produce rectangular waveform, triangular wave, saw wave, and square wave as its output. At the same time, the Multivibrator also has the ability to store binary information and synchronize multiple digital system operations.

Note : Quasi-Stable State is the Temporary Stable State of the Multivibrator at the time of its operation.


Post a Comment