The use of varistor

1 varistor can withstand a large pulse power, but the average power that can withstand is small.

2 The varistor is made up of zinc oxide as the main raw material. The failure mode of the varistor of the semiconductor electronic ceramic component is mainly short circuit. When the overcurrent is too large, the valve piece may be broken and open.

3 The error range of the varistor voltage is generally plus or minus ten percent. In test and practical use, the varistor voltage is usually reduced by 10% from the normal value as a criterion for varistor failure.

4 varistor is generally used in parallel in the circuit. When the voltage across the resistor changes sharply, the short circuit of the resistor will blow the current fuse to protect the varistor in the circuit, which is often used for power supply overvoltage protection and voltage regulation.

After the varistor sleeve heat shrinkable sleeve, the heat dissipation of the varistor is affected, and the large dissipated power is reduced, thereby affecting the power frequency voltage withstand capability of the varistor. Affected heat dissipation will also accelerate the aging of the varistor and affect the service life of the varistor.