Mastech MS2140A, Manual, Page: 12 / 15

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4.10 Current Measurement
1) For AC current move rotary switch to A~ position;
for DC current move rotary switch to A position.
2) Open the clamp head by pressing the trigger and
inserting the conductor to be measured.
3) When measuring AC current, the main display
shows the measured current value while the
secondary display shows the frequency of the
measured current
Note:
1) Measuring two or more wires together will cause
false readings.
2) The wire being measured should be centered within
the clamp.
3) “ ”indicates the maximum input AC/DC current is
600 A.
4) For higher accuracy, when measuring DC current
if Display shows non zero, press
“ZERO/REL”
button to reset the reading to zero.
Note:
1) When measuring low voltage source, the meter
When measuring low voltage sources, the reading
will fluctuate on the display when the test leads are
not connected to the circuit. This is normal due to
the high sensitivity of the Meter. The Meter will
display correct reading once the leads are
connected to the circuit.
4.12 Frequency and Duty Cycle
1) Insert the black test leads into “COM” input and red
test lead into “INPUT” input
2) Turn rotary switch to “Hz” position.
3) Connect test leads to the voltage source or
between loads.
Note:
Frequency range is 10Hz ~ 60MHz. For frequencies
below 10Hz, display will show “00.0.” For frequencies
about 60kHz, duty cycle measurement accuracy is
not guaranteed.
4.11 Voltage Measurement
1) Insert the black test leads into “COM” input and red
test lead into “INPUT” input, choose proper range.
2) Move rotary switch to V position. AC voltage is
default measurement. Press “FUNC” to switch to
DC voltage.
3) For mV measurement, press
“RANGE” button until
in mV range.
4) Connect test leads to voltage source or load.
5) Voltage measurement will be shown on main display.
4.13 Resistance
1) Insert the black test leads into “COM” input and red
test lead into “INPUT” input
2) Turn rotary switch to “ ” position for resistance
measurement.
3) Connect the test leads across the circuit or resistors
and read value on LCD.