Working Principle and Protection Measures of Varistor

Feb. 07, 2022

Everyday we can see varistors in power systems, surge suppressors, security systems, and motor protection. A varistor is connected to the circuit to realize the functions of voltage suppression and protection of the circuit. This article will talk about the working principle and protection measures of varistor.


Varistor is a commonly used electronic component, which can suppress transient voltage and is used in adapter circuit surge and transient protection circuits. Under normal working conditions, varistors can protect important components such as integrated circuits and other circuits and equipment to prevent component damage due to electrostatic discharge, surge and other transient currents.


In the process of adapting, engineers can connect the varistor to the protected circuit in parallel. After the completion of the parallel connection, if the voltage of the circuit system is higher than the limit value instantly, the resistance of the resistor will drop rapidly and let large current pass, so as to prevent instantaneous overvoltage from damaging the device.


When the input voltage is lower than the working voltage of the electrical appliance, the resistance of the varistor is extremely high, basically presenting an open circuit state, so it will not affect the normal operation of the device or electrical equipment. The power adapter connected to the varistor will cancel out the spark circuit and inrush current generated during the working process.


When an overvoltage pulse is superimposed on the power supply network, after connecting the varistor, the overvoltage peak waveform is flattened and limited to a certain amplitude. When opening or closing an inductive and capacitive load circuit, a switching spike appears in the DC waveform, and the varistor can absorb this back-electric offensive in the circuit, effectively protecting the switching circuit from damage.


Working Principle and Protection Measures of Varistor


The varistor can cleverly complete the circuit protection work because the varistor itself has the advantages of withstand voltage impulse current, small resistance temperature coefficient, and small size. It can help the adapter to ensure stable operation under the premise of integrating small packaging requirements. Varistor is very useful, we must know how to make good use of the role of varistor.


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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