OEM 20D 511k Metal Oxide Varistor Large Absorbing Transient Energy Capability

Metal Oxide Varistors

The Metal Oxide Varistor, or MOV for short, is a voltage dependent resistor in which the resistive material is a metal oxide, mainly zinc oxide (ZnO) as a ceramic material. Metal oxide varistors consist of approximately 90% zinc oxide as a ceramic base material and other filler materials for junction formation between zinc oxide grains.
Today, metal oxide varistors are the most common voltage clamping devices available for a wide range of voltages and currents. The use of metal oxides in their structure means that MOVs are very effective at absorbing short-term voltage transients and have higher energy handling capabilities.
Like ordinary varistors, metal oxide varistors start conducting at a certain voltage and stop conducting when the voltage drops below the threshold voltage. The main difference between standard silicon carbide (SiC) varistors and MOV-type varistors is that under normal operating conditions, the leakage current through the MOV zinc oxide material is small, while its Works much faster.
Characteristics of varistors
(1) Advantages: the voltage range is very wide, from several volts to several thousand volts, the surge current can be from tens to several thousand amperes, the response speed is fast, there is no polarity, no freewheeling, and the peak current withstand capacity is large. low price.
(2) Disadvantages: The clamping voltage is relatively high, which can generally reach 2 to 3 times the working voltage. In addition, pressure
The leakage current of the varistor increases with the increase of the number of surge impacts. The response time is longer and the parasitic capacitance is larger.
(3) Applicable occasions: DC power lines, low-frequency signal lines, or used in series with gas discharge tubes for AC power lines.

Specifications: