Method 1: Use a pointer multimeter to touch one foot of the capacitor with a reading pen, and then touch the other with another pen. At this time, the watch needle will quickly rise and slowly fall, which is the charging and discharging process of the capacitor. Clarify that the capacitor is good. If there is no change, the AC watch pen will show the above phenomenon, which is also good. If there is no charging and discharging or the watch needle does not fall after rising, it is considered that the capacitor is damaged. If it doesn't drop, it means the inside is broken down, and if the watch needle doesn't move at all, it becomes invalid. For large capacitors, use a 1X10 scale, and for small capacitors, use a 1X1K or 1X10K scale.

Method 2: Use a digital multimeter to measure capacitance: Set the gear to the capacitance (select the gear based on the capacitance value you measured), and use two probes to overlap the two legs of the capacitance during the test. The meter has a certain value, and then return to the infinite large position. Swap the probes and try again. This time, the data shows a slight error, and then return to the infinite large position to clarify that the capacitance is good. If it cannot return to the infinite large position, explain the leakage, and if it shows the infinite large position, explain the leakage, Clarify if there is an internal open circuit or no capacity.