Test method for damaging varistor

The varistor has a resistance value, but we use an ordinary universal meter, which is unable to read the number and is displayed as infinity. The method of measuring the varistor is as follows:

1 can choose varistor professional test equipment

2 You can use an oscilloscope first. Voltage test: When testing with an oscilloscope, set the input current to 1MADC. Test the voltage to see if it is consistent with the nominal voltage of the varistor. If the voltage is low, the varistor is damaged. The varistor has been short-circuited. If the varistor voltage is high or there is no nonlinearity, there is no curve bar, indicating that the varistor has been opened. Leakage current: When testing the leakage current, the nominal voltage value of the varistor can be checked in advance, and the oscilloscope test voltage can be adjusted to the corresponding voltage value range. If the current tested exceeds 100 microamperes, the varistor is inherently problematic because the varistor is controlled very small at the factory test and generally does not exceed 30 microamperes. Ordinary can only do these two, if you want to test other parameters, the oscilloscope has no way to test it, it needs more professional equipment.

3 can be tested with a universal meter. If the resistance value can be measured, it can basically be judged that the varistor is problematic and should not be used together.

If you use substandard ohmic resistors that are out of specification, the failure in use will also affect other components. Therefore, when the varistor is broken, when the corresponding varistor is not found temporarily, it can be removed, temporarily not used, as long as the voltage is stable, the use of your appliance will not be affected for a short period of time. Because it is usually connected in parallel in the circuit. If the varistor is damaged, do not replace it with a normal resistor because it has no effect. Ordinary resistors and varistors are two distinct components that cannot be replaced.