Zinc oxide varistors application principle

Varistor is a voltage limiting protection devices. Nonlinear characteristic use varistors, when an overvoltage occurs between two poles varistor 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 TGE Glass Coating varistors are: varistor voltage, current capacity, junction capacitance and response time.
Response time is ns grade varistor, faster than the air discharge, TVS tube slightly slower than under normal circumstances for an electronic circuit overvoltage protection to meet the requirements of its response speed. When the junction capacitance varistors are generally on the order of hundreds to thousands of pF range, in many cases should not be directly applied in the protection of high-frequency signal lines, the application of the AC circuit protection, since it greatly increases the drain junction capacitance current protection circuit is designed to take full account. Varistor flow capacity is large, but smaller than the gas discharge tube.
Varistors being protected electrical equipment or components used in parallel. When the circuit appears lightning over voltage or over-voltage transient operating Vs, TGE Metal Oxide Varistors(MOV) and the protection of equipment and components withstand Vs, due to the fast response of the varistor, it nanosecond time quickly render Nonlinear excellent electrical properties (see Figure 3 in the breakdown zone), then the voltage drop across the varistor rapidly, far less than the Vs, on such equipment and components to be protected actual withstand voltage is much lower than had voltage Vs, so that the equipment and components from over-voltage shocks.