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Measuring method
•
Unlock the T3CP current probe jaw. Open the jaw and insert the cable to be measured noting the
current direction indicator on the T3CP probe jaw in accordance with the direction of the current to
be measured. Insert the conductor under test in the middle of the measurement jaw.
•
Close and lock the T3CP current probe measurement jaw. Observe the waveform under test on
the oscilloscope screen. Adjust the oscilloscope sensitivity settings for the best waveform. Utilize
the current transfer ratio (oscilloscope input scaling) to transform the measured voltage from the
T3CP current probe into an accurate current measurement.
•
Change the oscilloscope Y axis from V(olts) to A(mps) if your oscilloscope supports this
functionality.
Frequently Asked Questions and Tips
•
Will the T3CP current probes work with oscilloscopes from brands other than Teledyne LeCroy and
Teledyne Test Tools?
The T3CP current probes will work with any oscilloscope that has a BNC input connector and a DC
coupled 1MΩ input. The T3CP probe is powered by a standard wall socket power adaptor that is
independent of the oscilloscope power.
•
Can the T3CP current probes measure small currents?
Yes. Each current probe in the T3CP range supports a dual range capability. The default power-on
setting is for the less sensitive range to be selected (the higher range), but the control box allows
the probe to be switched to a more sensitive range for lower current applications. The ranges for
each current probe, and the minimum measurable current is detailed in the specifications. When
measuring small currents, ensure that you accurately zero set and degauss the probe, and do not
change the position of the probe hand grip. To observe the smallest most sensitive current
waveforms please set the oscilloscope channel bandwidth filter to 20MHz to eliminate interference
and noise. When measuring extremely small current (a few mA for example), one could make a few
loops of the measurement cable through the probe measurement jaw and divide the result by the
number of loops to obtain the actual current value.
•
The T3CP is making inaccurate measurements, what can the problem be?
Check that the oscilloscope is set to 1MΩ input impedance. Check that the oscilloscope's input
channel is set to DC coupling and that the correct multiplication ratio is entered into the
oscilloscope. Degauss and auto zero the probe. Ground the scope channel and ensure that there is
no offset. Ensure that the lever on the probe jaw is in the locked position when making a
measurement.
•
When making measurements please do not let the measurement current exceed the value shown
by the maximum current input rating curve verses frequency. If the max continuous current is
greater than the rating curve verses frequency value then the probe may be damaged.
•
To measure accurately, please degauss and zero set the probe, and make sure the probe jaw is
locked during the measurement process.
•
Always set the input impedance of the oscilloscope to 1MΩ.
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