EPS3501 HV Sense Circuit

This is a HV Detector for input voltages up to 3.5kV. The LED changes color from green to red, if the input voltage is above 25V (adjustable). With an input resistance of op to 10G Ohm, the current is 350nA, so it does not affect most measurements in power supplys.

My Amersham Biosciences EPS3501 does only have an indication, if the output fet is actice, but it does not indicate, if the output caps are still charged. So there is deady voltage on the output for about 30 seconds aber disableing the output. This will make the device much safer to use.