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.
5 Model EX330 - Version 4.0 – 05/06