1147A 50 MHz Current Probe
Measurement Procedure
400
AC (f=50Hz)
300DC
200
100
Current consumption [mA]0
051015
Current to be measured [A]
Figure 4. Typical probe consumption
? Immediately after powering on, this unit may be subject to an appreciable
NOTE
offset drift due to the effect of self-heating. To counteract this, allow the unit
to warm up for about 30 minutes before carrying out measurement.
? When performing continuous measurements, it is necessary to be aware that
the zero offset voltage will drift if the ambient temperature changes.
? Under certain circumstances, oscillation may occur if the probe is connected
to the AutoProbe interface while the Infiniium is on. This does not indicate a
malfunction. Oscillation can be stopped and operation restored to normal by
opening and closing the sensor head.
? At some frequencies, some sound may be produced by resonance, this has no
effect on measurements.
? Measurement accuracy is affected by the position of the conductor being
measured within the clamp aperture. The conductor should be in the center
of the clamp aperture.
? Before making a measurement, press the opening lever until the "UNLOCK"
indication disappears and check that the sensor head is properly closed. If
the sensor head is not properly closed, accurate measurement will not be
possible.
? Accurate measurement may be impossible in locations subject to strong
external magnetic fields, such as transformers and high-current conductors,
or in locations subject to strong external electric fields, such as radio
transmission equipment.
? At high frequencies, common mode noise may affect measurements taken on
the high voltage side of circuits. If this occurs, reduce the frequency range of
the waveform measuring instrument or clamp onto the low-voltage side of the
circuit (as shown in figure 5), as appropriate.
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