What is Metal Oxide Varistor (MOV)?

What is an MOV?

Metal Oxide Varistors AKA MOVs are electronic devices designed to suppress surges in electrical and electronic circuits.

 


A Metal Oxide Varistor is a non-linear surge suppressor device, which is used to suppress sudden, high abnormal voltage transients or surges, especially during the power ON of a switch or natural thunder lightening situations.

This is mostly used in sensitive electronic circuits to make them safe against such catastrophic occurrences.

MOV is a non-polar device, which means you can connect it with any side. It is a voltage dependent device, which means this device will react to the changes in voltage conditions.

Therefore, MOV is specified to trigger whenever the rated voltage magnitude across their connections is exceeded.

The voltage rating at which an MOV may be defined to fire and short the transient to the ground is called its ‘clamping voltage’.

For an example, if the clamping voltage rating of an MOV is 420V then it will be switched ON whenever the voltage across it surpasses this value (420V).

When an MOV is switched ON or is triggered by a high voltage surge it shorts the voltage spike across its terminals, which prevents the spikes from entering the vulnerable electronic device attached next to it.

Here non-linear property works, it means there will be no action from MOV side until voltage across it goes above the rated voltage, and it will work when the voltage crosses the voltage limit.

 

How to connect an MOV?

Connection of MOV is very simple; MOV is across the Voltage via a fuse or fusible resistor.



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