Knowledge of the varistor can be better protected(II)

When the voltage at the two ends of the varistor is lower than the nominal rated voltage, the resistance value of the varistor is close to infinity, and there is hardly any internal current flowing through it. When the voltage at both ends of the varistor is slightly higher than the nominal voltage, the varistor will quickly pass through and change from high resistance to low resistance state, and the working current will increase sharply. When the voltage at both ends is below the nominal rated voltage, the varistor can be restored to a high impedance state. When the voltage at the two ends of the varistor exceeds its limiting voltage, the varistor will completely burn out and no longer be able to recover itself.