1. To judge the polarity, first adjust the multimeter to 100 or 1K ohms, assuming one pole is positive, connect the black test lead to it, the red test lead to the other pole, record the resistance value, and then discharge the capacitor, that is, let the two poles Contact, and then change the test lead to measure the resistance. The black test lead with a large resistance is connected to the positive pole of the capacitor.
2. Adjust the multimeter to the appropriate ohm gear. The principle of gear selection is: 1μF capacitors use 20K gears, 1-100μF capacitors use 2K gears, and larger than 100, μF use 200 gears.
3. Then connect the red pen of the multimeter to the positive pole of the capacitor, and the black pen to the negative pole of the capacitor. If the display gradually increases from 0, and finally the overflow symbol 1 is displayed, the capacitor is normal. If it is always displayed as 0, the capacitor is internally short-circuited. If 1 is displayed, the capacitor is internally disconnected.
