Monostable multivibrators, also known as one-shot multivibrators, are a type of IC (integrated circuit) that can be used as a timer. They have one stable and one unstable state. The unstable state is caused by a trigger pulse. This state is transient, so the circuit always returns to stability after a fixed time has elapsed.

Generally, monostable multivibrator circuits are composed of two transistors, coupled with one resistor-capacitor network and one resistor network. These networks are what determines the length of time before the circuit returns to its stable state, after being triggered. This type of IC can also be considered as a 1/2 astable type multivibrator.

What are monostable multivibrators used for?

This type of IC is used to produce a specific timed delay within a circuit. Therefore, they can broadly be used as timers or as pulse detectors in electronic equipment.

Types of monostable multivibrators

There are two types of a monostable multivibrator, they are;

Retriggerable monostable multivibrators will remain in the unstable state with repeated application of the trigger pulse.
Non-re-triggerable monostable multivibrators are unaffected by further trigger pulses and will remain in the unstable state only for the predetermined period of time.