How to test a capacitor.
This article shows you how to test a capacitor using analogue multimeter. Firstly short the capacitor leads for discharging it completely. Set the multimeter to high resistance mode. Connect the multimeter terminals to the capacitor leads. For electrolytic capacitors the positive terminal of multimeter must be connected to the positive lead of the capacitor and negative terminal of multimeter to the negative lead of capacitor. For other capacitor types, polarity is not an issue.
At the moment you connect the multimeter terminals to the capacitor leads, the multimeter needle will move to zero and then slowly move towards infinity and settle there. This will happen only if the capacitor under test is healthy.
- If the capacitor under test is short, the multimeter needle will go to zero and remain there.
- If the capacitor under test is open, the multimeter needle will not move (will remain at the infinity position which is the initial position for analogue multi meters).
- If the capacitor under test has leakage then the needle will first deflect to zero, and then slowly move towards infinity and will settle at a point before infinity.
This is only a rough test and for complete check up you need to varify the capacitor value using a capacitance meter.