How to Take Voltage Measurements of Electronics
- 1). Select the circuit ground or reference point. For automotive applications, this will be a connection on the chassis frame. Verify the chassis ground is clean and free of oil, dirt, rust, paint and other contaminates. Use a wire brush to clean the area of all contaminates. If you are taking a voltage measurement in an AC circuit, you will use the neutral wire (white wire) as your reference point.
- 2). Turn the DVM on and select the proper voltage. For automotive applications, this will be DC volts. If the meter has a DC voltage range, select 20 volts; most automobiles operate on 12-volt batteries. For AC voltage measurements, select AC volts.
- 3). Turn the electronic circuit on. Place the black probe on the reference point or chassis ground. Leave the probe in this location while you take your voltage measurements.
- 4). Place the red probe in the circuit. Monitor the voltage reading displayed on the meter. Do not short the positive probe and the negative probe while they are in the circuit.