Varistor resistive material is a semiconductor

"Mov varistor" is a kind of non-linear voltage characteristics of resistance devices, mainly used for in-circuit withstand overvoltage voltage clamp, absorb excess current to protect sensitive devices. English name called "Voltage Dependent Resistor" abbreviated as "VDR", or called "Varistor". Varistor resistive material is a semiconductor, so high voltage varistor is a variety of semiconductor resistor. "Zinc oxide" Now a lot of use of (ZnO) varistor, its main material divalent element zinc (Zn) and hexavalent elemental oxygen (O) of the composition. So from the point of view of materials, the zinc oxide varistor is a "Ⅱ-Ⅵ family-oxide semiconductor." In China Taiwan, metal oxide varistors  called "surge absorber", sometimes also referred to as "electric shocks (surge) suppressor (absorber) . "

Varistor is a voltage limiting protection devices. The use of nonlinear characteristics of the varistor, when an overvoltage occurs in between the two poles of the varistor, the varistor voltage can be clamped to a relatively fixed voltage value, in order to achieve protection of the post-stage circuit. The main parameters of varistors are: varistor voltage, current capacity, junction capacitance and response time.