what is varistor

A varistor is an electronic component designed to protect electrical circuits from excessive voltage spikes or sudden surges. It acts as a voltage-dependent resistor that absorbs excess electrical energy and prevents it from reaching sensitive components of a circuit. The varistor works by altering its resistance based on the applied voltage. Under normal operating conditions, it presents a high resistance to the flow of electricity. However, when the voltage exceeds a predetermined threshold, the varistor responds by rapidly reducing its resistance, effectively diverting the excess voltage away from the circuit. This helps to protect delicate components and prevent damage that could result from sudden electrical surges. Varistors are commonly used in a wide range of electronic devices, including power supplies, computers, telecommunication systems, automotive electronics, and home appliances. They provide an essential line of defense against transient voltage events, such as lightning strikes, power line surges, and electrostatic discharges. Overall, varistors are crucial components that provide reliable and cost-effective protection for electronic circuits and equipment, ensuring their longevity and uninterrupted performance.