How to use a voltage meter

Voltage meters, including voltmeters and multimeters, are essential tools for electricians and technicians. Using these devices, you can accurately detect and measure voltage within a circuit.

In this article, we’ll walk through how to use a voltage meter safely, breaking the process down into simple steps.

Let’s begin!

Gather the necessary tools and materials

Before you start, make sure you have the right tools and materials for the job. At the very least, you’ll need:

• Your voltmeter or multimeter
• Two test leads (one red, one black)

Check over the voltmeter or multimeter to ensure the device is clean and intact. Most multimeters have three parts—a display (either digital or analogue), a selection knob, and at least two ports.

Set the dial

Most voltmeters and multimeters feature large dials you can use to select the measurement mode. The symbols for the voltage settings are typically V~ (denoting alternating current measurement) or V- (denoting direct current measurement). Sometimes, these measurements may be combined.

If you’re unsure whether to select AC or DC measurement, as a general rule, household outlets and circuits use AC, while portable devices and batteries use DC.

Some voltage meters have manual range settings. If this is the case, you’ll need to set the dial above the maximum voltage you expect to measure. For example, if you’re testing a standard Australian wall outlet with a voltage of 230V, set the dial to the lowest option higher than 230 V~.

Insert the test leads

Most voltage testers have two leads, one black, and one red. Each lead features a probe at one end and a metal jack covered with plastic at the other.

Insert the black jack into the corresponding port, typically labelled ‘COM’ for common. When measuring voltage on a multimeter, insert the red jack into the port labelled ‘V.’

Refresh safety considerations

Before you begin testing, it’s crucial to make sure you’re aware of safety considerations when working with and around electricity. Always keep your fingers clear of the jack’s metal probes when testing live circuits, and never touch two probes together.

We recommend wearing insulated rubber gloves and safety goggles to remain safe when performing a voltage test.

Begin testing

Once you’ve researched how to use your voltage meter safely, you can begin testing. If you’re testing a battery, the process is simple: 

1. Set the multimeter to “V-” for DC voltage,
2. Touch the black lead to the battery’s negative terminal,
3. Touch the red lead to the battery’s positive terminal.

If there’s no reading, you may need to switch the meter dial to ‘DC+’ or ‘DC-’ or drop the voltage setting by single steps until a reading appears.

If you’re testing AC voltage, you’ll need to select the AC voltage option (V) and, if necessary, the appropriate range. Perform the test by touching a probe to each conductor.

Conclusion

Measuring voltage is a critical skill for anyone working with electrical circuits. By following the steps we’ve outlined above, you can take safe and accurate measurements using your voltage meter.