The multilayer varistors array filter connector design

Varistor(Metal Oxide Varistor)

The varistor is a variable resistor. In a lower application voltage, the varistor acts as a conventional high-resistance resistor and obey Ohm's law, when more than a certain threshold voltage, the device becomes highly conductive, and exhibit a low impedance at high voltage. Varistor conductive clamp voltage is applied to the specified maximum value, this value is the device can withstand. With these features, the varistor has been applied in electronic products and away from the transient overvoltage protection circuit. Varistor at a low voltage, similar to a ceramic capacitor, and as such, it can be used as part of the filter processing of continuous noise. Why, then, varistors are not often used in filtering applications, to enable them to complete a dual role - ie continuous noise attenuation and transient voltage suppressor?

Fortunately, recent innovations have changed this confusing situation. The multilayer planar array filter capacitor, such as transient protection function can be realized. Using the the multilayer varistor plane array filter connector from the transient protection for product design provides an alternative.

The varistors pulse level

When a varistor is used as a filtering applications, one of its limit is: downgrade its protective function, this may be a the voltage surge repetitive impact results.

Varistors are made of ceramic material. Most varistor whose main component is the oxide of zinc (ZnO). While adding a small amount of other oxides, such as bismuth, cobalt, manganese, etc.. Therefore, the varistor is sometimes referred to as metal oxide varistors MOVs(Metal Oxide Varistor).

In the manufacturing process, the raw ceramic powders are mixed, shaped, and then fired. And metalization to achieve electrical connection. In the ceramic during firing, forming a polycrystalline structure (Figure 1). The added metal oxides to move to the edge of the crystal body, the formation of the PN junction of the semi-conductive layer. This means that the average grain size is determined by the original powder formulation and firing temperature. When the the unit grain boundaries applied voltage is below 3.6 volts, the grain boundary exhibits a high resistive. Above the threshold, it will be switched into a high conductivity.(Metal Oxide Varistor)