Metal Oxide Varistor (MOVs)

A varistor is an electronic component with a "diode-like" nonlinear current–voltage characteristic. The name is a portmanteau of variable resistor. Varistors are often used to protect circuits against excessive transient voltages by incorporating them into the circuit in such a way that, when triggered, they will shunt the current created by the high voltage away from sensitive components. A varistor is also known as voltage-dependent resistor (VDR). A varistor’s function is to conduct significantly increased current when voltage is excessive.