Mar. 28, 2022
The development of science and technology has created electronic products, and electronic products such as televisions, computers, mobile phones, etc. are inseparable from electronic components. Take varistor as an example, varistor has a wide range of applications. Today, this article will take you to understand varistors from three aspects: definition, working principle, and matters needing attention when purchasing varistors.
1. Definition
A varistor is a resistive device with nonlinear volt-ampere characteristics, which is mainly used for voltage clamping when the circuit is subjected to overvoltage, absorbing excess current to protect sensitive devices. The English name is "Voltage Dependent Resistor", abbreviated as "VDR", or "Varistor". That is to say, a varistor is a resistor whose resistance value changes with the change of the applied voltage. Its main purpose is to sense, resist and absorb surge energy of abnormal overvoltage.
2. Working Principle
When the voltage applied to the varistor is lower than its threshold, the current flowing through it is extremely small, which is equivalent to a resistor with infinite resistance. That is, when the voltage applied to it is lower than its threshold, it acts as an off-state switch.
When the voltage applied to the varistor exceeds its threshold, the current flowing through it surges, which is equivalent to an infinitesimal resistance. That is, when the voltage applied to it is higher than its threshold, it acts as a closed state switch.
Precautions for Purchasing Varistors
1) The surge current absorbed by the varistor should be less than the maximum flow rate of the product;
2) The clamping voltage of the varistor should be less than the voltage of the protected equipment;
3) The nominal discharge current of the varistor should be greater than the possible surge current in the line;
4) The voltage value of the varistor should be greater than the voltage peak value in the actual circuit, that is, the power supply voltage continuously applied to both ends of the varistor should be less than the "continuous working voltage value" in the varistor specification;
5) For lines that transmit signals at high frequencies, the capacitance should be as small as possible;
6) The varistor can absorb a large surge current, but cannot withstand the continuous current above the mA level, which needs to be considered in the overvoltage protection.
Choose a regular manufacturer when purchasing varistors will save you a lot of trouble. If you're not sure about the selection, you can always turn to a professional manufacturer for help. Dongguan Zhixu Electronic Co., Ltd. (also JYH HSU(JEC)) has engaged in the electronic component industry for many years, and our technical engineers can help you solve related problems. Don’t hesitate to contact us if you have questions or need samples.
PTC Themistors in the Circuit - Factors to be Considered
Mar. 28, 2022
About Temperature Control Thermistor
Mar. 28, 2022
Super Capacitor Application in Solar Energy System
Mar. 28, 2022
+86 181 2299 5593
+86 18122995593
+86 769 8831 3605
Beside Luchong Bridge, Hou Road, Caibai Village, Daojiao Town, Dongguan, Guangdong, China
Navigation
