Overview
The F-90 series of current probes are used to measure currents flowing on flat or curved surfaces. The shielding effectiveness of a structure, case or housing can be determined by measuring the currents flowing on the inner and outer surfaces of the structure. Each probe is calibrated and can be used to locate the leakage points on a surface. The probe is highly sensitive to the direction of the current flow allowing the surface currents on a structure to be completely mapped. The probe sensitivity is maximized when the axis of the probe is perpendicular to the current flow. Surface probes are composed of a dielectric base to raise it above the surface reducing the disturbance of the current flowing in the surface to less than 10 percent. Surface probes can operate in radiated fields up to 100 volts per meter without significant interference from case leakage. The sensing circuit of the surface probe is well shielded by its case. The Model F-90 has a transfer impedance of 0.08W (±2 dB) from 10 kHz to 1 MHz. Model F-91 has a transfer impedance of 1.4W (±2 dB) from 5 MHz to 100 MHz, and the Model F-92 is usable from 40 MHz to 400 MHz with a typical transfer impedance of 0.9W(±2 dB). Primary powerline currents of 5000 amperes will not alter the transfer impedance characteristics. Models F-90 and F-91 have a type N connector, are 38.1 mm wide, 88.9 mm long and 50.8 mm high. The F-92 has a BNC connector and is 38.1 mm wide, 76.2 mm long and 44.45 mm high.
