Four ways to test capacitors

1.Multimeter test method

For fixed capacitors larger than 0.01F. The R & TImes; 1k block of the multimeter can be used to directly test the capacitor for charging process and internal short-circuit or leakage, and the capacity of the capacitor can be estimated according to the amplitude of the pointer swinging to the right. During the test operation, first touch the two pins of the capacitor with two test leads, and then touch the test leads again. If the capacitance is good, the pointer of the multimeter will swing to the right, and then quickly return to the infinite position to the left. The larger the capacitance, the greater the amplitude of the pointer swing. If you repeatedly switch the probe to touch the two pins of the capacitor, the pointer of the multimeter does not swing to the right, indicating that the capacity of the capacitor has fallen below 0.01 μF or has disappeared. In the measurement, if the pointer cannot swing back to the infinity position after swinging to the right, the capacitor is leaking or has broken down.

2.Simple detection method of fuse

A fuse (the rated current In of the fuse is determined by the following formula: IN = 0.8 / C (A), where C is the capacitance of the capacitor) and the capacitor to be detected are connected in series to a 220V AC power supply. The fuse has broken, indicating that the capacitor has a short circuit. If the fuse of the fuse does not burst, after a few seconds of charging, cut off the power supply and use a screwdriver with an insulation handle to short-circuit the two poles of the capacitor. A spark indicates that the capacitor is good. On the contrary, it means that the capacitance of the capacitor has become smaller or has been opened. Judging the quality of the capacitor by this method should be repeated several times to get the correct conclusion.

3. Incandescent bulb and capacitor series detection method

Connect the incandescent bulb and capacitor in series to a 220V AC power supply. If the brightness of the incandescent bulb is darker than if it is directly connected to the 220V AC power supply, the capacitor is good; if the incandescent bulb is not bright, it indicates the inside of the capacitor under test It has been disconnected; if the brightness of the incandescent bulb is the same as that of the directly connected to 220V AC power source, it means that the capacitor has a short circuit inside.

4. Megohmmeter test method

It can also be tested with a megohmmeter (250V class). Shake the handle. If the pointer is at infinity, it means that the capacitor is open. If the pointer is at zero, it means that the capacitor is short-circuited. The grounding test of the capacitor can also be done by connecting the terminal of the megohmmeter to the terminal and the shell of the capacitor respectively. Shake the handle, if the pointer is at zero, it means that the capacitor is grounded.