The Applications of High voltage varistor

To protect telecommunication lines, transient suppression devices such as 3 mil carbon blocks (IEEE C62.32), ultra-low capacitance varistor metal oxide , and avalanche diodes are used. For higher frequencies, such as radio communication equipment, a gas discharge tube (GDT) may be utilized.[citation needed] A typical surge protector power strip is built using xatge MOV . Low-cost versions may use only one varistor, from the hot (live, active) to the neutral conductor. A better protector contains at least three varistors; one across each of the three pairs of conductors. In the United States, a power strip protector should have an Underwriters Laboratories (UL) 1449 3rd edition approval so that catastrophic MOV failure does not create a fire hazard.

Electrical characteristics of varistor metal oxide

A varistor metal oxide remains non-conductive as a shunt-mode device during normal operation when the voltage across it remains well below its "clamping voltage", thus varistors are typically used for suppressing line voltage surges. However, a polymer arrester may not be able to successfully limit a very large surge from an event like a lightning strike where the energy involved is many orders of magnitude greater than it can handle. Follow-through current resulting from a strike may generate excessive current that completely destroys the varistor.

Lesser surges still degrade it, however. Degradation is defined by manufacturer's life-expectancy charts that relate current, time and number of transient pulses. The main parameter affecting varistor life expectancy is its energy (Joule) rating. As the energy rating increases, its life expectancy typically increases exponentially, the number of transient pulses that it can accommodate increases and the "clamping voltage" it provides during each transient decreases. The probability of catastrophic failure can be reduced by increasing the rating, either by using a single varistor of higher rating or by connecting more devices in parallel. A varistor is typically deemed to be fully degraded when its "clamping voltage" has changed by 10%. In this condition it is not visibly damaged and it remains functional (no catastrophic failure).

Mov metal oxide varistor

The structural characteristics of the varistor varistor metal oxide different from ordinary resistor, which is based on nonlinear characteristics of semiconductor material made of
Ohm's law to comply with ordinary resistor, and varistor voltage and current is nonlinear relationship was special. When applied across the varistor voltage is lower than the nominal rated voltage, resistance value varistors approaches infinity, almost no current flows through the interior. When the voltage across the TGE Metal Oxide Varistors(MOV) slightly higher than the nominal rated voltage, the varistor will quickly breakdown conduction by a High Performance Varistor state to a low resistance state, current also increases dramatically.

mov metal oxide varistor

TGE Mov varistor is a non-linear voltage characteristics of the resistance of the device is mainly used in the voltage clamp circuit withstand over-voltage, absorbing excess current to protect sensitive devices. English name called "Voltage Dependent Resistor" abbreviated as "VDR", or called  mov varistor. Varistor resistive material is a semiconductor, so it is a variety of semiconductor resistor. "Zinc oxide" Now a lot of use of (ZnO) varistor metal oxide, its main material divalent element zinc (Zn) and hexavalent elemental oxygen (O) of the composition. So from the point of view of materials, the zinc oxide  High voltage varistor is a "Ⅱ-Ⅵ family-oxide semiconductor." In China Taiwan, varistors called "surge absorber", sometimes also referred to as "electric shocks (surge) suppressor (absorber)."

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