how to test leaking capacitors using DMMs?

[elex_enthusiast]

hi there,

im quite confused on how to test leaking capacitors using my DMM..i used to determine leaking capacitors using an analog multimeter using resistance function but i have no idea how to perform such test using a digital meter.....please give me hints..any tips would be greatly appreciated...

[Anks]

Are you referring to coupling caps leaking DC?

[Dave]

Connect the DMM in series with your charged capacitor and connect both to that same voltage you charged your cap to.
The DMM has to be set to DC voltage. By knowing the input resistance of your DMM and by reading the voltage on it when the circuit settles, you know the leakage current through you cap.

[robrenz]

Why not just use the same setup with the DMM in current mode measuring leakage current directly?

[Dave]

Silly me, I just assumed his meter wasn't capable of measuring currents that low, because he was asking the question.

[mos6502]

1. Apply a voltage to the cap (a 9v battery is handy for this) and measure the current. You probably need a uA range for this.

2. Use the resistance mode. As soon as you touch the probes to the cap terminals, you should see the resistance become very low and then slowly increase into the single digit megaohm range. If your meter shows a low resistance value the cap is leaky.