What is the function of a varistor?

What is the function of a varistor?

Varistors are used to protect a circuit from high voltage surges. When a high voltage surge is applied to a circuit, the outcome is usually catastrophic to the circuit. A capacitor may be installed across the signal lines.

What do the numbers on a varistor mean?

k = a constant for the component. V = applied voltage. n = value for the device style. Typically for silicon carbide the value of n is between about 3 – 7, but for zinc oxide device the value can be in the region of 20 – 50 making the characteristic much sharper. Varistor characteristic.

What is a metal oxide varistor used for?

Varistors, also called metal-oxide varistors (MOVs), are used to protect sensitive circuits from a variety of overvoltage conditions. Essentially, these voltage-dependent, nonlinear devices have electrical characteristics similar to back-to- back Zener diodes.

How do I read varistor code?

Touch one meter probe to the free varistor lead and the other probe to the connected lead. Read the resistance on the meter. If it reads nearly infinite resistance, the varistor is still good. If it reads very low resistance, the varistor is blown.

What is the difference between fuse and varistor?

Unlike the fuse or circuit breaker which offers over-current protection, the varistor provides over-voltage protection by means of voltage-clamping in a similar way to the zener diode.

How are varistors rated?

Multi-layer varistor (MLV) devices provide electrostatic discharge protection to electronic circuits from low to medium energy transients in sensitive equipment operating at 0–120 volts dc. They have peak current ratings from about 20 to 500 amperes, and peak energy ratings from 0.05 to 2.5 joules.

Is a dimmer a rheostat?

is that rheostat is an electrical resistor, with two terminals, whose resistance is continuously variable by moving a knob or slider while dimmer is a rheostat that is used to vary the intensity of a domestic electric light.