Re: HV Measurement - Back to Basics

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "David Speck by way of Terry Fritz <teslalist-at-qwest-dot-net>" <dave-at-davidspeckmd-dot-org>

Jim,
If you were not going to use a precision rectifier on the low voltage end 
of the chain, then you would have to use a high voltage rectifier before 
the dropping resistors.  I guess it's about a wash in terms of difficulty 
-- building a 15 kV full wave bridge for the high end vs. a precision 
rectifier at the low end of the divider network.  I guess that if you had a 
set of HV diodes available, then it wouldn't be too hard to tackle the HV 
end approach.
Dave

Tesla list wrote:

>Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><jimlux-at-earthlink-dot-net>
>
> > tool, and make it the resistor closest to the meter, and hence, ground.
>Of
> > course, I am assuming that you are measuring a DC voltage.  If you are
> > measuring unrectified AC MOT output, you will have to add a precision
> > rectifier circuit, a much more complicated issue.
> >
>
>Don't need a precision rectifier... The few tenths drop in the diode bridge
>is insignificant compared to the huge drop in the resistor.  You calibrate
>it empirically anyway, so the RMS/Average/Peak issue doesn't arise (that is,
>you put in 15 kV ACRMS, adjust a trim pot til the meter reads FS, and you're
>done).  If you were trying to measure a few volts, or make average voltage
>measurements with varying waveforms, then a precision rectifier might be
>needed.
>
>
>
>