Varistor function:

The first advantage of the rheostat is that when the threshold value of the rheostat itself is greater than the external given voltage, the current value in the circuit is very small, and its own valve will be equivalent to an inoperable valve. As the voltage increases, the resistance value in the circuit decreases and the current increases, thereby reducing the influence of the voltage on the circuit. Through this function, we can protect the circuit in the varistor from the influence of voltage, so that the voltage value will not change too much.

2. Precautions for selection of varistors:

1. No matter how the voltage changes, its fluctuation extreme value shall not exceed the allowable extreme value of the rheostat. If the continuous working voltage exceeds the fluctuation extreme value, the service life of the varistor will be shortened.

2. When the varistor is connected between the power line and the ground, the voltage between the power line and the ground may rise for some reasons, such as lack of good grounding. The voltage used by the rheostat equipment must be higher than the voltage between the power line and the ground.

3. The current absorbed by the varistor in the working process must be less than the product flow as much as possible.