Talking about the function and detection method of varistor

The varistor is generally used in parallel in the circuit. When the voltage across the resistor changes and exceeds the rated value, the internal resistance of the resistor becomes sharply small, exhibiting a short-circuit condition, and the current fuse connected in series is blown to protect. Varistors are used in circuits and are often used for power supply overvoltage protection and regulation.

With the varistor parameter tester, the varistor voltage, leakage current, and @linear coefficient can be measured. In the amateur work situation, the multimeter is set to 10k when measuring, the test pen is connected to the two ends of the resistor, and the multimeter should display the resistance value indicated on the varistor. If the deviation is large, the varistor is damaged.

If the varistor is damaged, it is time to suspend use and look for new replacements in order to avoid smashing into other capacitors.