How Varistor Is Damaged

Jan. 08, 2022

Varistor is a voltage-limiting protection device whose non-linear characteristics is used. When an overvoltage occurs at its two electrodes, the varistor can clamp the voltage to a relatively fixed voltage value, thus realizing circuit protection. The varistor also has a very important function, that is, it is used for transient overvoltage protection in the circuit. Although its flow capacity is large, its energy capacity is not large.

In addition, because its large impulse current pulse width is much smaller than the actual pulse current width of high and medium power semiconductor systems, short circuits or burnouts and failures often occur. The varistor commonly used in the market is a varistor made of (ZnO) zinc oxide. The main reasons for its damage are as follows:

â‘ Insufficient Withstand Voltage

This is well understood. If the working voltage of a product is 220V but the varistor you use is 180V or less, it will definitely break down and be damaged.

How Varistor Is Damaged

â‘¡ Excessive Current And Surge

For example, MYG05K stipulates that the current passed is 0.1mA, and the nominal voltage of MYG07K, MYG10K, MYG14K, MYG20K refers to the voltage across the varistor when a 1mA DC current is passed. The use varistor in certain devices, especially devices that need to be plugged and unplugged very often, will cause the varistor to be damaged faster, because the surge of the product during plugging and unplugging is relatively large (the equipment at both ends is not connected to the ground), and the device itself and TVS have weakened protection capabilities, resulting in a higher damage rate.

In addition, varistor of poor quality tend to be damaged easily, so finding a regular manufacturer to purchase varstors  is essential. Dongguan Zhixu Electronic Co., Ltd. (also JYH HSU(JEC)) has a full range of varistor and capacitor models with guaranteed quality. JEC has passed ISO9001:2015 quality management system certification; JEC safety capacitors (X capacitors and Y capacitors) and varistors have passed national certifications of the main industrial powers across the world; JEC ceramic capacitors, film capacitors and super capacitors are in compliance with environmental protection indicators. We have over 30 years of manufacturing experience. If you have technical questions or need samples, please contact us.

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