EMC combined di/dt current probe

A current sensor for the analysis of conducted radio-frequency interference (RFI), based on an air-cored and screened Rogowski coil, is presented. The sensor is realised as a convenient current clamp, suitable for on-site measurements, e.g. in industrial environments. The probe is insensitive to strong mains power frequency currents, electric and magnetic fields, and parasitic air gap. With an incorporated wide-band amplifier a transimpedance characteristic of 0.5 /spl mu/H in parallel with 5 /spl Omega/ is realised. The effective frequency range is larger than 9 kHz-30 MHz. It can be used both for time-domain measurements using oscilloscopes and as a probe (with a suitable antenna factor) for electromagnetic compatibility (EMC) spectrum analysers.