I have a 5KV DC output from a Cockcroft-Walton multiplier. The current is around few microamps as per the simulation. To prevent discharge, the 200Mohm resistor holds the voltage of the Cockcroft-Walton multiplier stable. The 200Mohm resistor is rated for 22KV for the voltage tolerance.
The current sense resistor is rated for 600V.
Is it safe to connect the current sense resistor like this?
The voltage across the resistor comes around 0.300V approximstely (calculated using Ohm's law.)
Is there a way to isolate the measuring setup from the high voltage?
They all share the same ground, and there is a seperate circuit that discharges the capacitors of the multiplier safely within itself without the current flowing to the common ground.
The ADC can measure differential voltages.
Best Answer
You might want to slap a 1N4148 (or, better, two in series) across the 10K. That way if something were to spark or arc over it won't damage the instrumentation amplifier. A few K in series with the inputs wouldn't hurt.
There's not a lot of reason for the instrumentation amplifier, though the buffer helps because the input resistance of the ADC is not all that high (would load the input about 1.5%).
If you provide an isolated power supply you can add an I2C isolator and isolate the ADC from whatever is talking to it. You may have trouble finding parts (DC-DC and isolator) that are inexpensive and rated for 5kV continuous, so it depends on what the voltage across the isolation barrier will be.