ETS-Lindgren 94606-6 Current Probe - Manual (Page 45)

Operation | 45
Signal Injection
Applies to Model 94111 Series only.
Current probes may be used to inject RF currents into test conductors when
performing susceptibility tests. Injection is best accomplished with current probes
that do not have internal loading. Internal loading will absorb part (or most) of the
driving power and can seriously limit the maximum levels of voltage and current
that the current probe can handle as an injection device.
The current probe does not have an internal load and therefore is suited for
signal injection. However, it will be limited by connector voltage rating (500 V)
and by the thermal limit of the coil windings. A maximum continuous injection
current into the current probe coils of 4.2 amps may be used; two or three times
this level may be used for short periods of time. When injecting pulse signals, the
average current should be held within the above limits, and the peak voltage held
below 500 V.
Because of variable circuit impedances, there is no easy way to compute the
RF current that may be injected into the test conductor. The practical way to
determine the injected current is to measure it with a second current probe on the
test conductor. The second current probe can be any model that covers the
frequency range of interest.