Overview
A varistor is a resistor with a nonlinear current-voltage (I-V) relationship, often made from metal oxide materials. Its resistance decreases as the applied voltage increases, making it ideal for protecting circuits from voltage spikes. The I-V curve of a varistor is nonlinear: at low voltages, it behaves like a regular resistor, but at higher voltages, the current increases sharply due to its voltage-dependent resistance.

Significance

• Surge protection in electrical circuits.

• Nonlinear behavior in voltage-dependent resistive materials.