User`s guide

7
34134A AC/DC DMM Current Probe
Operation
Operation
1 Connect the probe to the multimeter or other instrument.
CAUTION Be sure to observe the polarities: red = positive terminal, black = common terminal.
2 Select the multimeter range which best corresponds to the measured current.
For better reading stability, you may use the DMM 2 Volt range and let the probe “warm
up” for one minute before zeroing.
The Current Probe has a dual output, DC V output in DC and AC V output in AC.
• The “1 V/A” range has an output signal of 1 mV/mA AC/DC with an output of 2
volts representing 2 amps present in the conductor being measured.
• The “10 mV/A” range has an output signal of 10 mV/A AC/DC with an output of
500 millivolts representing 50 amps present in the conductor being measured.
3 Zero the probe in DC and in DC coupled AC measurements.
When the 34134A Current Probe has been used for a current measurement and then
removed from the conductor, a small amount of residual magnetism often remains in
the core. This residual magnetism will cause the voltmeter to show a small DC reading
even though there is no current passing through the jaws of the probe. The residual
magnetism should not cause a problem for AC current measurement because the AC
voltage function in most multimeters is AC coupled. DC offset caused by the residual
magnetism will contribute to reading errors, but can be minimized by using the zero
adjust knob to show a reading of 0 a few counts on the multimeter (probe not clamped
on a conductor).
There will always be some instability and noise generated by the Hall sensor, the earth
magnetic field and environmental noise. This is particularly noticeable on the most
sensitive range, 1 V/A (1 mV/mA), where you may have up to 5 mV of uncertainty,
which cannot be “zeroed out.” “Zero” the probe while it is connected to the DMM and
on the range to be used. Let the probe warm-up for one minute before zeroing. Turn
the zero adjustment knob until the probe is zeroed.
4 Observe the output polarities for DC measurement.
5 Clamp the probe on the conductor to be measured and read the current flowing
directly on your meter.
The output of the probe is 10 mV/A AC/DC or 1 mV/mA AC/DC. If your meter
indicates a negative reading during DC measurements, this simply means that the
current flow is in the opposite direction of the arrows marked “I” on the probe or that
the probe connections are reversed (polarity).
6 After measurement, turn the probe OFF.
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34134A.book Page 7 Wednesday, March 25, 2009 4:09 PM