To test a capacitor with a multimeter, discharge the capacitor, set the multimeter to test for resistance then interpret the reading. There are other testing methods other than resistance that can be used. Since capacitors store voltage, the multimeter is also capable of reading volts, so if the multimeter being used has a capacitance meter, the actual capacitance value is given.
- Discharge the capacitor
Discharge the capacitor by placing a screwdriver or wire across the leads. This is done to prevent a shock that could damage the multimeter.
- Set the multimeter
Since the resistance of the capacitor is tested, set the multimeter to read in the ohm range between 10,000 and 1,000,000 ohms.
- Use the multimeter
Touch the probes to the capacitor's leads. If the capacitor is electrolytic, touch the red probe to the positive lead and the black probe to the negative lead. If the capacitor is not electrolytic, the polarity doesn't matter.
- Read the multimeter
If the multimeter reads in the range of 10,000 ohms and increases to near infinity, the capacitor is normal. If the reading is very low or nothing, the capacitor has a short and is defective. If the reading is immediately infinite, the capacitor is both open and defective.