You’re probably familiar with clamp on current probes, but chances are you don’t know much about the Rogowski current probe. A Rogowski coil produces a voltage that is proportional to the rate of change (derivative) of current enclosed by the coil-loop. The coil voltage must be integrated for the probe to provide an output voltage that is proportional to the current signal. This also means that the Rogowski can’t perform at DC, but can operate to a frequency lower than most AC clamp-on current probes.
Table 1 highlights the key performance attributes of three different clamp on current probes. The comparison results are based on the PEM CWT015, Tektronix P6022 and Teledyne Lecroy CP031 current probes. The three probe heads are shown in Figure 1.
Table 1. A comparison of current probes.