The discriminate between ceramic capacitors and varistor

Ceramic capacitor is similar to varistor. They are all blue, round and small. Some people do not know how to mix ceramic capacitors and varistor. If the function is not normal, the circuit will burn out. Although they look like, they have different functions.

Varistor is a kind of resistance device with nonlinear volt-ampere characteristics. It is mainly used for voltage clamping when the circuit is subjected to overvoltage, and absorbs excess current to protect sensitive components. The main function is to withstand abnormal overvoltage and protect the circuit. The ceramic capacitors are capacitors made of ceramic materials as a medium, coated with a metal film on the surface of the ceramic, and then sintered as a high-temperature electrode. The main function is to block, couple, bypass and Capacitors such as filters are used.

Generally, the varistor position marks on the circuit board are: VSR, VDR, RV, etc., and the ceramic capacitors are marked with "C". The appearance of varistor is generally blue. The size is generally 5D 7D 10D 14D 20D 25D, etc. Its surface lettering is based on XD and then followed by 10XK 2XXK 18XK and other marks, those marks indicate the pressure resistance of varistor, such as printed 10D 471K then means that this is varistor, then the diameter is 10mm, the withstand voltage is 470V and the error range is 10%.

The appearance of ceramic capacitors is also blue, the appearance is very similar to varistor, but D is not used as the size. Generally, the printing is directly printed with 10X 1KV 22X 1KV, etc., for example, 102M 400V is printed, indicating that the capacity of this ceramic capacitors is 102 Withstand voltage is 400V The error range is 20%.

In most cases, we can use the printing logo to identify whether it is a ceramic capacitors or a varistor, but there may be printing errors, unclear printing, no printing, etc. At this time, we have to use the instrument to measure the business opportunities, so In order to be guaranteed.

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