Ac Voltage Measurements; Dc Voltage Measurements - Extech Instruments EX330 User Manual

AC VOLTAGE MEASUREMENTS

WARNING: Risk of Electrocution. The probe tips may not be long enough to contact the live
parts inside some 240V outlets for appliances because the contacts are recessed deep in the
outlets. As a result, the reading may show 0 volts when the outlet actually has voltage on it. Make
sure the probe tips are touching the metal contacts inside the outlet before assuming that no
voltage is present.
CAUTION: Do not measure AC voltages if a motor on the circuit is being switched ON or OFF.
Large voltage surges may occur that can damage the meter.
1. Set the function switch to the VAC position.
2. Insert the black test lead banana plug into the negative COM jack.
Insert red test lead banana plug into the positive V jack.
3. Touch the black test probe tip to the neutral side of the circuit.
4. Touch the red test probe tip to the "hot" side of circuit.
5. Read the voltage in the display.
6. If the measured AC voltage exceeds the highest range of the meter
(refer to the specification table) an audible tone will sound.

DC VOLTAGE MEASUREMENTS

CAUTION: Do not measure DC voltages if a motor on the circuit is being switched ON or OFF.
Large voltage surges may occur that can damage the meter.
1. Set the function switch to the VDC position.
2. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive V jack.
3. Touch the black test probe tip to the negative side of the circuit.
Touch the red test probe tip to the positive side of the circuit.
4. Read the voltage in the display.
6 EX330-EN v5.0 06/14