Metal Oxide varistor (MOV)
A varistor or a voltage-dependent resistor (VDR), are resistors whish resistance varies with the applied voltage. Generally, varistors were indeed constructed by connecting two rectifiers, such as the copper-oxide or germanium-oxide rectifier in antiparallel configuration. At low voltage the varistor provides high electrical resistance which decreases as the voltage is raised. Varistors that are primarily based on sintered ceramic metal-oxide materials which exhibit directional behavior only on a microscopic scale. are commonly known as the metal-oxide varistor (MOV).
MOVs are used as control or compensation elements in circuits either to provide optimal operating conditions or to protect against excessive transient voltages. When used as protection devices, they shunt the current created by the excessive voltage away from sensitive components when triggered.
Variable resistors, such as the potentiometer and the rheostat, have ohmic characteristics. But The varistors are non-ohmic varying resistors.
Use of a MOV
The typical use of a MOV is to protect electronic devices or equipment from voltage spikes, surges, and transients in the power supply. When the voltage in a circuit exceeds a certain level, the MOV responds by absorbing the excess voltage and diverting it to the ground, protecting the connected equipment from damage.
MOV devices are commonly used in a wide range of applications, including power supplies, motor control circuits, Lighting Circuits and telecommunications equipment, among others. They are also widely used in surge protectors and power strips to protect devices such as computers, TVs, and other sensitive electronics from power surges.
Connection of MOV
MOV are commonly used along with fuse in parallel to the circuit that is to be protected.
