How to Test Capacitors with a Multimeter

1. Using an Analog Multimeter (Pointer Type)

• Test Range: ｓｅｌｅｃｔ R×10, R×100, or R×1K on the ohmmeter.

• Steps:

  1. Discharge the capacitor (short its terminals with a resistor).

  2. Connect the black probe to the capacitor’s (+) terminal and the red probe to the (–) terminal.

  3. Observe the needle movement:

     • Good Capacitor: Needle swings right quickly, then slowly returns left to the starting position.

     • Shorted Capacitor: Needle swings right but does not return (stuck near 0Ω).

     • Leaky Capacitor: Needle returns but stops mid-scale (e.g., 50–200kΩ).

     • Open Capacitor: Needle does not move (no charging).

2. Using a Digital Multimeter

• Test Mode: Set to R×1K (resistance mode).

• Steps:

  1. Connect probes to the capacitor (polarity irrelevant for digital meters).

  2. Watch the reading:

     • Good Capacitor: Value rises rapidly until displaying "1" (overflow).

     • Faulty Capacitor: Stays at "0" (short) or "1" (open) with no change.

3. Testing High-Voltage Capacitors (Leakage Check)

For capacitors with rated voltage > multimeter battery voltage (e.g., 9V):

• Use R×10K range to perform a reverse-charge test:

  • Black probe (–) to capacitor’s (+) terminal, red probe (+) to (–) terminal.

  • Good Capacitor: Needle swings right, stabilizes at 50–200kΩ.

  • Leaky Capacitor: Needle drifts right slowly or fails to stabilize.

Key Notes:

• Electrolytic Capacitors: Require correct polarity during testing.

• Safety: Always discharge capacitors before testing to avoid damage/meter errors.

• Limitation: Analog meters struggle with small capacitance values; use a capacitance meter for precision.

Quick Reference Table: