working principle

The varistor is a voltage limiting protection device. Utilizing the non-linear characteristics of the varistor, when the overvoltage appears at both ends of the non-linear varistor, the varistor can clamp the voltage to a relatively fixed voltage value, thereby protecting the subsequent circuit. Understanding of the specific implementation process: When the voltage across the varistor is lower than its threshold voltage, the flowing current is extremely small, which is equivalent to a resistance with infinite resistance. That is, it acts as an open switch when the voltage applied to it falls below its threshold. When the voltage across the varistor rises above its threshold voltage, the current flowing through it surges, equivalent to a resistor with infinitesimal resistance. That is to say, when the voltage applied to it is higher than its threshold, it is equivalent to a closed switch.

The main function

Varistors are mainly used for transient overvoltage protection such as lightning strikes and surges.