The varistor is made of metal oxide semiconductor materials. When the applied voltage is below the breakdown voltage, the varistor is in a high-impedance cut-off state and does not work on the circuit. When the applied voltage suddenly exceeds its breakdown voltage , the varistor will quickly turn on and blow the fuse so as to protect the subsequent circuit from being burned. So it is generally connected to the entrance of the mains.
The varistor is very similar to the capacitor, and it is generally marked with 10D471K or 14D471K. 10D means the diameter is 10mm.471 indicates that the breakdown voltage is 470V, and the general damage of the varistor is manifested as leakage, breakdown, and bursting.
The resistance value of varistor is infinite under normal conditions, so it can be judged whether it is normal using the high resistance level of the multimeter to measure a varistor.
This article is provided by JYHHSU (JEC) Electronics (also Dongguan Zhixu Electronics), a manufacturer of electronic components such as capacitors and resistors.
Post time: Aug-20-2024