What is a multivibrator? And what are the different types of multivibrators?

When it comes to electronics and electrical engineering, there are certain terms that you will be faced with regularly. One of the first (and possibly most basic) concepts that you’ll need to familiarize yourself with is the multivibrator, or multivaristor if you prefer the original terminology. Let’s look at what a multivibrator is and why it’s so important in electronics and electrical engineering and then take a look at some of the different types of multivibrators you might encounter in your electronics career.

What is a multivibrator?
A multivibrator is an electronic circuit that switches between two states. These states can be two or more voltages, two or more currents, or two or more levels of some other parameter such as temperature. A common type of multivibrator found in electronics is called a flip-flop which can be used to store data. The term multivibrator came from the fact that it often switches back and forth between multiple voltage levels.

The three main types of multivibrators
There are three main types of multivibrators: astable, bistable, and monostable. An astable multivibrator has an on-time that is equal to its off-time and does not need to be reset once it has been started. A bistable multivibrator has an on-time and an off-time that can be set by external controls. A monostable multivibrator only has one state that can’t be changed without being reset.

The astable multivibrator
An astable multivibrator is an electronic circuit that generates an alternating square waveform. It switches between two states, typically low voltage and high voltage. The output frequency (cycles per second) can be tuned by adjusting one or more resistors.

The monostable multivibrator
A monostable multivibrator, also known as a one-shot, is an electronic circuit that outputs one pulse in response to input. An external trigger signal must be applied to initiate the pulse output. The duration of this pulse (commonly called the time-out) is determined by a resistor and capacitor combination which form an RC network. The time-out can range from microseconds to minutes or hours depending on these components and other factors such as temperature or voltage.

The bistable multivibrator
A bistable multivibrator, also known as a flip-flop, is an electronic circuit that has two stable states which it switches between. This type of circuit can be used to store information or to generate pulses. There are two basic types of bistable multivibrators: RS and JK.