Selection and application of varistor

1. Commonly used voltage-sensitive voltage, that is, dielectric strength or threshold voltage. It refers to the voltage value measured in many cases when the nominal voltage-sensitive voltage DC current is passed into the varistor. The varistor voltage limit of its product is allowed at approximately 10PF-10KV. Can be correctly selected according to the detailed requirements. In general, the nominal voltage sensitivity = "1" 2VAC is the instantaneous value of the nominal voltage of the circuit. VAC is the square root value of the rated AC voltage. The choice of voltage value of ZnO varistor is very important, which is related to protection effectiveness and service life.

2. It is often said that the current capacity, that is, the instantaneous value of the pulse current is the pulse current value when the temperature is 30 ℃. In terms of the specified impulse current waveform and the number of times of the defined impulse current, the change of the voltage sensitive voltage is not higher than the pulse current value when the pulse current is ±10 ℃. In order to extend the service life of the varistor, the surge current absorbed by the ZnO varistor should be less than the given product flux. However, from the protection effect, it is necessary to select a larger flow rate. In many cases, the actual flux generated is difficult to accurately calculate, using a 2-20 rated current varistor.