ETS-Lindgren's Model 91550-1 and 91550-1L Current Probes are extremely broad frequency range sniffer probes covering 20 Hz to 100 MHz. Both series of current probes have a calibration available down to 20 Hz, which make them ideal test equipment for such test methods as MIL-STD-462 CEO1 and RSO1. In particular, the newer CEO1 limits which are dependent on EUT current/voltage requirements are more stringent than the older fixed limit CEO1 requirement. Coupled with the widespread use of microwave spectrum analyzers (such as the HP8566) with degraded sensitivity below 100 Hz, sensitivity at low audio frequencies is very important. Use of the 91197-1 current probes with the HP8566B allows current measurements below 80 dBA at 20 Hz. This is more than 6 dB below MIL-STD-461 and related conducted emission limits, including common mode limits on submarines.
The 91550-1 and 91550-1L have 3.18 cm (1.25 in) window, making them suitable for measurements on most power cables (AWG 4/0 cable, good for several hundred Amps, is 12.7 mm (0.5 in) diameter, exclusive of insulation). Probe saturation current is compatible with the current carrying capacity of wires placed in its window. In those cases where the window is not large enough, our 93686-1 probe has similar sensitivity with a 6.65 cm (2.62 in) window.