Metal Oxide Varistor (MOV) Principle

MOV (Metal Oxide Varistor) is an electronic component with a significant non-ohmic current–voltage characteristic.

MOVs are often used to protect circuits against excessive transient voltages by incorporating them into the circuit in such a way that, when triggered, they will shunt the current created by the high voltage away from the sensitive components.

A MOV’s function is to conduct significantly increased current when voltage is excessive. A MOV remains non-conductive as a shunt mode device during normal operation when voltage remains well below its “clamping voltage”. If a transient pulse (often measured in joules) is too high, the device may melt, burn, vaporize, or otherwise be damaged or destroyed.

MOV introduces a “capacitor” like behavior in the circuit which makes then unusable in telecom or communication systems. MOVs are normally placed at the input of field input or power.

Every card is protected against surge and over-voltage through MOVs. MOVs are placed at the input field signals of DI and AI card. Protection against over-voltage in power line is achieve through a dedicated hot swap controller that cuts off the power when an over-voltage is detected.

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MOV (Metal Oxide Varistor), is a very sensitive to the voltage non-linear resistor assembly. MOV’s folder type device exhibited the applied voltage decreases the voltage will increase, they usually exhibit characteristics when the conduction current one mA (milliamp) dropped voltage and start crossing this device, this voltage level is conduction This decline voltage across the MOV when, there will be a large increase in the current device, in a short reaction must be included when determining the true level of protection for this device considerations.

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A MOV(Metal Oxide Varistor) contains a ceramic mass of zinc oxide grains, in a matrix of other metal oxides (such as small amounts of bismuth, cobalt, manganese) sandwiched between two metal plates (the electrodes).

They can be connected in parallel for increased energy-handling capabilities. MOVs can also be connected in series to provide higher voltage ratings or to provide voltage rating between the standard increments.

A Metal Oxide Varistor remains non-conductive as a shunt mode device during normal operation when voltage remains well below its “clamping voltage”. If a transient pulse (often measured in joules) is too high, the device may melt, burn, vaporize, or otherwise be damaged or destroyed.

The varistors must on all accounts be connected parallel to the electronic circuits to be protected.
The Metal Oxide Varistor or MOVis a voltage dependent, nonlinear device that provides excellent transient voltage suppression.

The Metal Oxide Varistor is designed to protect various types of electronic devices and semiconductor elements from switching and induced lightning surges.When exposed to high transient voltage, the MOVclamps voltage to a safe level.

A metal oxide varistor absorbs potentially destructive energy and dissipates it as heat, thus protecting vulnerable circuit components and preventing system damage. Varistors(Metal Oxide Varistor) can absorb part of a surge…

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