VARISTORS
Varistors with two-pronged nonlinear passive circuit elements whose resistance varies with voltage are used in AC and DC circuits; Switching is used to protect other elements from high voltage against possible sudden voltage surges due to noise and lightning.
The resistance of the varistor is very high and is connected in parallel to the circuit. If the voltage source of the circuit exceeds the maximum voltage of the varistor, the varistor resistance decreases abruptly so that it becomes short-circuit and protects the circuit from instantaneous changes.
Parafudur, as a varistor type, is connected between high voltage lines and ground. It prevents the transformer from being damaged by transferring the high current to the ground in case of lightning.
Varistors, which can be used for different voltage values according to their dimensions, have high energy absorbing capacities. With its fast response time, it provides protection against very short voltage surges that are not prolonged. Explosion is possible if exposed to high-voltage over prolonged periods.
