Over Voltage Protection Device-Voltage Dependent Characteristic

Voltage Dependent Characteristic Transient Voltage Suppressors (Varistors) are voltage-dependent electrical resistors with symmetrical V/I characteristic and the breakdown region, their resistance value decreases with increasing voltage, thus “short – circuiting” further rises in over voltage.  

The Prevention of Over Voltage In other words, as long as the voltage increases above the threshold of the TVS, the suppressor will draws a rapidly increasing current, and then the over voltage is considerably attenuated away from the protected circuit, that is why the inherent protection of the equipments should be supplemented by including specific components that will raise the withstand capabilities to the required level. Varistors provide protection against all kinds of over voltage and prevent electronic equipment from being damaged by transient events.