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Measuring high voltages

I have a circuit that generates a floating ( both sides) ~ +/- 1500V. The final output is generated by a standard diode cap multiplier block, giving 1mA current. The +ve output is monitored via a 1G resistor into an opamp then an ADC. The negative output is allowed to follow the positive which is in a closed loop controlto set the output voltage. What is the best way to monitor the -ve output ? 100:1 probe ? a fet probe? 1000:1 probe ? Output is pulsed in the small uS range... TIA

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Reply to
TTman
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What do you mean by 'floating'? Does the measuring device also float, or is it referred to some other potential/ground? How accurate do you need this to be?

Also - are you expecting to follow the dynamics of this pulsed voltage? To what bandwidth?

Reply to
Frank Miles

How is it pulsed if it is derived from a CW multiplier?

Tim

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Reply to
Tim Williams

Here's a reasonable priced 20ua meter, series seven 10meg and one 5 meg resistors in series with the meter. and it will read full scale at 1500V. Maybe I'd use ten 10meg in series and the you could see an over voltage condition. Caution High Voltage, us proper techniques and insulation. Also remember it's a negative voltage when hooking it up.

20ua will have negligible affect on your voltage. Mikek 
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Reply to
amdx

Forgot the meter,

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Reply to
amdx

The -ve of the + supply is connected to the pos of the -ve supply, which is ground referenced. 2-3% would be good...

No just the peak DC voltage which is about 50uS

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Reply to
TTman

there's a front end pulsed oscillator feding the D/C multiplier.

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Reply to
TTman

I'd try one of those TV flyback HV probes. They are about 10G ohms and will lightly load the supplies. But they are not frequency compensated, you might have to build one yourself if frequency response is important.

Cheers

Reply to
Martin Riddle

On a sunny day (Mon, 30 Mar 2015 23:17:37 +0100) it happened TTman wrote in :

If it is truely a 50 us pulse from 0 to whatever, then you could use a capacitive divider, and measure AC.

Else as you use a resistor divider for +, why not do the same for -. BTW if you connect both together the output should be zero for DC. If you have problems with negative voltages, then hang a resistor from the end of the - divider to some stabilized +, so reference + of the ADC range

Reply to
Jan Panteltje

Nope, like 1.1 G.

Reply to
jurb6006

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