Testing the voltage of a circuit with a voltmeter can provide you with valuable information when you're making repairs or diagnosing issues. Voltmeters are found in any professional electrician's tools, and they are affordable enough to be purchased by any homeowner.
Things You'll Need
- Voltmeter or multimeter
Plug the test probes into the voltmeter. If the meter's plugs are color coded, make sure the colors match the probes. If the plugs are not color coded, match the "+" or "-" with the corresponding leads.
Select which current type you will be testing. Voltage options are AC (alternating current, found generally in homes) and DC (direct current, found in vehicles). Many digital meters automatically select these options once testing begins.
Turn on the meter.
Touch the red or "+" lead to the positive side of the circuit or wire. If you're testing an AC circuit, either side of the circuit can be tested with the red or black probe. DC circuits require that the positive probe test the positive side of the circuit.
Touch the black, or "-," probe to the negative side of the circuit or wire. The meter displays the voltage, if there is any, on the circuit.
Tips & Warnings
- When you test an AC wall outlet, either test probe can be placed into either side of the plug (not the grounding prong plug).
- When you test a circuit, never allow the test probes to touch one another. This can result in electric shock, meter overload, flying sparks and even fire.
- Photo Credit Polka Dot Images/Polka Dot/Getty Images
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