Tektronix TCP300A, User Manual

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Getting Started
Ground Lead
The TCP305A and TCP312A probes include a 6-inch ground lead. The ground
lead grounds the shield around the probe transformer at the probe end of the
cable. This allows you to move the ground connection closer to the circuit you are
measuring, thereby improving high frequency shielding. The ground lead clips
onto the ground connector on the bottom of the probe.
Figure 3: Connecting the ground lead
The ground lead on the current probes is intended to be used in high dV/dt
environments. The probes have a grounded shield between the conductor under
test and the current sense transformer. Any capacitively-coupled current will then
fl ow in the ground instead of the transformer windings.
When you take high frequency measurements, connect the probe ground lead to
the probe ground connector and attach the alligator clip directly to RF ground to
improve EMI rejection at high frequencies (2 MHz and above). This will reduce
ringing and help bypass capacitively-coupled RF currents which can
fl ow into
the probe cable. In some cases, it may be helpful to move the ground lead or
reposition the probe away from noise sources in the circuit under test.
6 TCPA300/400 Ampli fi ers and TCP300A/400 Series Current Probes User Manual