I have an ionizer. I want to measure the voltage and current in a wire one end of which is exposed to the ionised atmosphere around the ionizer, and the other end of which is grounded. This involves measuring very high voltage (many thousands) and very small current (microamps or perhaps less). How do I do this? Any advice is very much appreciated, thank you!

 

You need an electrostatic voltmeter

http://en.wikipedia.org/wiki/Electrostatic_voltmeter

http://photonics.bfioptilas.co.uk/Electrostatic+Voltmeter+Instruments-267.htm

 

Thank you for this. The voltmeters you referred to only go up to 2kV,whereas I am looking to measure higher potentials. Also, what about measuring the current?

 

To measure the current, connect a current meter between ground and the low end of the wire.

If you want to watch proceedings on a scope, connect a low value (100 ohms, 1 ohm or less) instead of the meter and connect the scope Y input (set to DC) across it to monitor the voltage.

 

For low-level current measurements, look around on the Keithley Instruments web site, in particular see the Low Level Measurement Handbook. Sometimes older Keithley products can be found on Ebay for fairly low prices.

Sam Goldwasser's Basics of High-Voltage Probe Design may also be of interest. An electrostatic voltmeter as suggested by studiot may be a better choice to avoid loading the circuit.