Shop Varistors: Metal Oxide Varistors & Surge Protection on Amazon.com
Varistors, also called voltage-dependent resistors (VDR), have an electrical resistance that changes with the voltage applied to it and are non-ohmic. Varistor is a blend of the term varying resistor. Its resistance decreases as increased voltage is applied. A varistor may be used in surge protection to keep voltage spikes from damaging equipment. The most common type is a metal oxide varistor (MOV), which is used for circuit protection of telecommunication lines and is rated by the range of voltages they can protect against. It also has a rating for the percentage change in its clamping voltage it can tolerate before it is unfit for further service. A Bourns varistor is a familiar brand of this electrical component. Varistors are available individually and in kits for electronics projects. Metal oxide varistors used in power strips may trigger an indicator light on the power strip to indicate whether the component has been damaged by sustained excessive voltage.