Operation - Extech Instruments 380973 Instruction Manual

5. OPERATION

5.1 True RMS Measurements
The 380973 incorporates True RMS technology meaning that non-sinusoidal (triangle,
sawtooth, etc.) or distorted waveforms can be measured more accurately than averaging
meters. The degree of distortion that the meter can accurately measure is determined by
the 'crest factor' of a waveform (ratio of peak value to rms value).
5.2 Measurement Preparation
1. Use the Rotary Selector switch (7) to select the appropriate range and function. Ensure
that the selected range is suitable for the measurement to be taken.
2. If the measured current is higher than the selected range for long periods of time,
overheating can result which may damage the meter.
3. Do not measure current on high voltage conductors (> 600V).
5.3 AC Current Measurements
WARNING: Ensure that all test leads are disconnected
from the meter's terminals before proceeding.
1. Set the Rotary Selector switch to the 400 or 600 Amps
AC (~) range.
2. Clamp the transformer jaw around one of the
conductors under test. Open the jaw via the jaw trigger
(3). Ensure that the clamp closes completely around
the conductor.
3. Read the displayed measurement value on the display.
5.4 DC Voltage Measurements
Warning: Maximum DC input voltage is 600V. To avoid
electrical shock or damage to the instrument, do not attempt
to measure any voltage exceeding this limit.
1. Set the Rotary Selector switch to the 600Volts DC (----)
range.
2. Connect the black test lead to the COM terminal and red
test lead to the V/Ω/uF terminal.
3. Connect the test leads to the circuit, component, or other
device under test (refer to figure at right).
4. Read the displayed measurement value on the LCD.
5.5 AC Voltage Measurements
Warning: Maximum AC input voltage is 600V. To avoid
electrical shock or damage to the instrument, do not attempt
to measure any voltage exceeding this limit.
1. Set the Rotary Selector switch to the AC Volts (~) range.
2. Connect the black test lead to the COM terminal and red
test lead to the V/Ω/uF terminal.
3. Connect the test leads to the circuit, component, or other
device under test (refer to figure at right).
4. Read the displayed measurement value on the LCD.
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