User`s guide

Making Measurements 2
Measuring AC or DC Current
U1273A/U1273AX User’s Guide 73
Figure 2-31 DC current display
NOTE
• To measure current, you must open the circuit under test, then place
the multimeter in series with the circuit.
• Turn off power to the circuit. Discharge all high-voltage capacitors.
Insert the black test lead into the COM terminal. Insert the red test lead
in an input appropriate for the measurement range.
• If you are using the A terminal, set the rotary switch to .
• If you are using the µA mA terminal, set the rotary switch to for currents
below 5000 μA (5 mA), or for currents above 5000 μA.
• Press to cycle between DC current measurement, AC current
measurement, AC+DC current measurement, or % scale current
measurements.
• Reversing the leads will produce a negative reading, but it will not
damage the multimeter.
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CAUTION
• To avoid blowing the multimeter’s 440 mA fuse, use the µA mA
terminal only if you are sure the current is less than 400 mA. See
Figure 2-34 for test lead connections and function selection. Refer
to the “Input warning” section for information on the alerts the
multimeter uses when leads are not used correctly for current
measurements.
• Placing the probes across (in parallel with) a powered circuit when
a lead is plugged into a current terminal can damage the circuit you
are testing and blow the multimeter's fuse. This happens because
the resistance through the multimeter's current terminals are very
low, resulting in a short circuit.