1. Short-circuit the two pins of the capacitor with a pointer multimeter to discharge, and connect the black probe of the multimeter to the positive pole of the electrolytic capacitor. The red probe is connected to the negative pole (for the pointer multimeter, the probe is adjusted when measuring with the digital multimeter). In normal conditions, the probe should first swing in the direction of small resistance, and then gradually return to infinity. The larger the swing amplitude of the meter needle or the slower the return speed, the greater the capacity of the capacitance. On the contrary, the smaller the capacity of the capacitance. If the meter needle does not change at some point in the middle, the leakage of the capacitance is indicated. If the resistance indication value is very small or zero, the capacitance has broken through the short circuit. Because the battery voltage used by the multimeter is generally very low, it is more accurate to measure the capacitance with low withstand voltage, and when the withstand voltage of the capacitance is high, Although the measurement is normal during striking, the leakage or breakdown may occur when high voltage is added.

　　2. Measure the capacitance with a digital multimeter, set the gear to the capacitance (select the gear according to the capacitance value you measured), use two probes to overlap the two feet of the capacitance during the test, the meter has a certain value, and then return to the infinity position, change the probe and try again. This time, the displayed data size is slightly biased, and then return to infinity, indicating that the capacitance is good. If it cannot return to infinity, it indicates that the leakage, such as infinity, It indicates that there is an internal open circuit or no capacity.