# Meauring voltage from a DC 15kV - 50kV source with around 1 microampere of current

I am building a DC energy generating device that at the moment generated DC power at 15K-50k Volts at 1 microampere.

I am considering using a high impedance ADC (1G ohm, 0.3V range, 2 nanoamperes current, 32 bits.)

When I plan out a voltage divider circuit to work with this ADC my voltage or current is always out of range.

I would ideally like to tune my circuit so current is between 0-0.3V and I have 2 nanoamperes for the ADC to sample. It also requires a very expensive 100G ohm or more resistor.

Is there a way (with op amps perhaps) to reduce the voltage but keep the current high and be more cost effective?

32 bits is far more precision than I need so even if the range becomes more like 0-0.003V that is acceptable.

• Use a lot of cheap, lower value resistors in series to make a big resistor. Nov 21, 2021 at 6:31
• Before you design your first prototype I suggest you to read norm UL 60950 for your own safety. Nov 21, 2021 at 8:58
• Is the problem that the current is at high potential relative to ground, or that the current is small relative to the converter error currents? Does a battery-powered current monitor that sends its measurements via bluetooth to a cell phone app fit the need? Nov 21, 2021 at 9:09
• "When I plan out a voltage divider circuit to work with this ADC....", you do need a shunt, not a divider if you want to measure the current. Post a schematics of what you have done. I would rather buffer the shunt voltage with a very high 100G electrometer opamp, not a cheap way. Nov 21, 2021 at 9:44