How to Measure a Capacitor With a DVM

Measure the voltage across a capacitor with a digital volt meter.

You caneasure the voltage of a capacitor to know whether the device is still charged. Capacitors store electrical energy for use by other electrical components. A capacitor consists of two parallel plates with a voltage difference across them that creates the stored energy. The greater the voltage and capacitance of the capacitor, usually measured in microfarads, the more energy may be stored. A digital volt meter makes a convenient tool to check whether a capacitor has a voltage and therefore a stored energy.

Things You'll Need

• Digital volt meter

Instructions

1. Turn on the digital volt meter and switch its measurement dial to the direct current (DC) voltage setting. DC voltage is denoted by a letter "V" with horizontal lines above it.

2. Connect the red volt meter probe to the positive port on the device. This port may be labelled "V" for voltage. Plug the black volt meter probe into the negative port on the device. This port may be labelled "COM" for common ground.

3. Touch and hold the red probe of the volt meter to the terminal of the capacitor labelled "+." Touch and hold the black probe of the volt meter to the terminal of the capacitor labelled "-." The voltage currently on the capacitor is shown on the volt meter screen. If the reading is zero or too low for the volt meter to measure, then the capacitor has no stored energy.

References

• Georgia State University: Energy Stored on a Capacitor
• Georgia State University: Capacitance