Varistor is an energy storage element

What does a varistor mainly do?

A varistor is a resistive device with non-linear voltammetric characteristics, mainly used for voltage clamping when a circuit is subjected to overvoltage, absorbing excess current to protect sensitive devices.

What is a varistor's volt-ampere characteristic?

A varistor has the volt-ampere characteristics in which current suddenly starts to flow through the device at a certain voltage, as shown in Figure 1. Varistors are used to protect semiconductor devices in electronic and electric circuits from overvoltage.

When does current start to flow through a varistor?

A varistor has the volt-ampere characteristics in which current suddenly starts to flow through the device at a certain voltage. The varistors are used to protect semiconductor devices in electronic and electric circuits from overvoltage.

What is a varistor resistor?

The varistor resistance is related to the voltage applied at both ends. When the voltage added to the varistor is within its nominal value the resistance of the resistor is in an infinite state with almost no current passing through.

How does a varistor protect a circuit?

A varistor is a voltage-limiting protection device. By using the non-linear characteristics of a varistor, when an overvoltage occurs across a non-linear varistor, the varistor can clamp the voltage to a relatively fixed value, thus protecting the back-end circuit.

How does voltage affect a varistor?

Under normal voltage, the varistor is in a high-impedance state with a very small leakage current. When subjected to overvoltage, the varistor quickly becomes a low resistance state, and the overvoltage energy is absorbed by the varistor in the form of discharge current.