An earth-isolated optically coupled wideband high voltage probe powered by ambient light

An earth-isolated optically coupled wideband high voltage probe has been developed for pulsed power applications. The probe uses a capacitive voltage divider coupled to a fast LED that converts high voltage into an amplitude-modulated optical signal, which is then conveyed to a receiver via an optical fiber. A solar cell array powered by ambient laboratory lighting charges a capacitor that, when triggered, acts as a short-duration power supply for an on-board amplifier in the probe. The entire system has a noise level $\le$0.03 kV, a DC-$5$ MHz bandwidth and a measurement range from $-6$ to $2$ kV; this range can be conveniently adjusted.