WRN-333 WRN-332 WRN-340 WRN-341 WRN-342 K type thermocouples
WRN-333 WRN-332 WRN-340 WRN-341 WRN-342 K type thermocouples, the varistor is composed of a metal oxide (mainly zinc oxide) material. It is a clamping device. It uses the non-linear characteristics of the varistor. When an overvoltage occurs between the two poles of the varistor, the varistor can clamp the voltage To a relatively fixed voltage value, so as to achieve the protection of the subsequent circuit. Varistors have been widely used in lightning protection of electronic equipment.
Selection of varistor:
From the perspective of suppressing transient interference, the varistor voltage should be reduced as close as possible to the working voltage of the circuit being protected; from the perspective of increasing the component life, it is necessary to open the gap between the two. The general compromise is: for AC working circuits, the varistor voltage is 2.2 times the working voltage; for DC working circuits, the varistor voltage is 1.5 times the working voltage.
Selection of flow rate: In practical applications, the maximum surge current absorbed by the varistor should be less than its maximum flow rate. For the same application, when the maximum flow rate doubles, the life of the varistor also doubles.