How about using a high voltage probe that used to be commonly used to measure anode voltages of TV picture tubes. There were probes that had a KV meter built into the probe and there are ones that were used with VOM'S. Joe K3WRY In a message dated 3/22/2018 8:59:08 PM Eastern Standard Time, bruce.griffi...@xtra.co.nz writes:
Electrostatic voltmeter? Either the classical version or the modern electronic variant perhaps? Bruce > > On 23 March 2018 at 13:33 "Dr. David Kirkby" <drkir...@kirkbymicrowave.co.uk> > wrote: > > I want to measure a high voltage, but put minimal load on the circuit. > Looking at the Keithley electrometers, the input resistance is at least 200 > T ohms, but they tend to have a maximum of 200 V FSD. > > A 2000 V source, and a 200 T ohm resistor gives a current of 10 pA, which > itself is easy to measure. But one can't buy 200 T ohm resistors. I looked > at RS in the UK, and the highest value resistor I could find is 1 T ohm, > and they are £163 each (around $200). > > Maybe fabricating ones own resistor is possible, but I suspect there's a > better way. Keithely manage to keep a 200 T ohm resistance on the 200 mV > range, and there's no way that can be measured with an ammeter, which would > require an ammeter with a full scale deflection of 1 fA, which is much > smaller than the 2 pA FSD on its most sensitive range. > > Any thoughts? > > Dr David Kirkby Ph.D C.Eng MIET > Kirkby Microwave Ltd > Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD, > Essex, CM3 6DT, United Kingdom. > Registered in England and Wales as company number 08914892 > http://www.kirkbymicrowave.co.uk/ > Tel 01621-680100 / +44 1621-680100 > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
