Making Measurements 2
Measuring AC or DC Current
U1271A/U1272A User’s Guide 93
Measuring AC or DC Current
To measure current, you must open the circuit under test,
then place the multimeter in series with the circuit.
To measure AC or DC current, proceed as follows:
1 Turn off power to the circuit. Discharge all high- voltage
capacitors. Insert the black test lead into the
terminal. Insert the red test lead in an input appropriate
for the measurement range.
i If you are using the terminal, set the rotary switch
to .
ii If you are using the terminal, set the rotary
switch to for currents below 5000 μA (5 mA), or
for currents above 5000 μA.
Never attempt an in-circuit current measurement where the
open-circuit potential to earth is greater than 1000 V. Doing so will
cause damage to the multimeter and possible electric shock or
personal injury.
To avoid possible damage to the multimeter or to the equipment under
test:
• Check the multimeter’s fuses before measuring current.
• Use the proper terminals, function, and range for your
measurement.
• Never place the probes across (in parallel with) any circuit or
component when the leads are plugged into the current terminals.
To avoid blowing the multimeter’s 440 mA fuse, use the terminal
only if you are sure the current is less than 400 mA. See Figure 2-33 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.
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