ETS-Lindgren 94606-6 Current Probe - Manual (Page 29)

Principles of Operation | 29
4.0 Principles of Operation
Before connecting any components or
operating the probe, follow the safety
information in the ETS-Lindgren
Product Information Bulletin included with your
shipment.
The current probe is an inserted-primary type of radio frequency current
transformer. When the probe is clamped over the conductor or cable in which
current is to be measured, the conductor forms the primary winding. The
clamp-on feature of this probe enables easy placement around any conductor or
cable.
Circuit
The circuit is that of a radio frequency transformer, as illustrated on page 30.
Because the current probe is intended for clamp-on operation, the primary shown
on page 30 is the electrical conductor in which interference currents are to be
measured. This primary is considered as one turn since it is assumed that the
noise currents flow through the conductor and return to the source by way of a
ground conductor such as a frame, common ground plane, or earth. On some
current probe models the secondary output terminals are resistively loaded
internally to provide substantially constant transfer impedance over a wide
frequency range.