EMC testing

EZ-17, reactive output impedance

Question

For EMC measurements, I have EZ-17 available, model .02 and model .03. In datasheet "reactive" is specified for the output impedance of model .03. What is the difference between the Model .02 and the Model 03 in terms of EMI measurements?

Model 02 Model 03
Frequency range 20 Hz to 100 (200) MHz 20 Hz to 100 (200) MHz
Range with constant transducer (-3dB) 1 MHz to 100 MHz 2 MHz to 100 MHz
Transducer factor reduced by 20 dB/decade in range 20 Hz to 1 MHz 20 Hz to 2 MHz
RF connector N female N female
Output impedance 50 Ω (f ≥ 10 MHz) reactive

Answer

The model .02 of the current probe EZ-17 has a terminating resistor, this leads to a forced matching to 50 Ohm, which is preferred for emission measurements and also ensures a defined VSWR.

The model 03 does not have a terminating resistor, this is advantageous for immunity measurements, because the maximum injected power can be used for field generation. The maximum power that can be fed in is correspondingly higher, since it is no longer limited by the terminating resistor. The specification 'reactive' therefore means not terminated or not defined.

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