Re: Finally a Field Mill!

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:

 > Original poster: "Charles Brush by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <cfbrush-at-interport-dot-net>

 > One of the topics that naturally comes up on this list from time to time is
 > the measurement of electric fields.  A couple of years ago there was a very
 > interesting thread about using x-ray tubes for voltage measurements of a
 > running Tesla coil (I think Dr. Resonance or someone tried this....in a
 > ditch for shielding!).  One of the devices which naturally comes up in any
 > measurement discussion is the field mill or "generating voltmeter", and
 > these are devices I have always been interested in.
 >....
 > I also have
 > an electrostatic voltmeter, and it will be interesting to see how its
 > results compare to those of the field mill.    Anyway I'd certainly be
 > interested in any comments!  I know of some good field mill plans and other
 > info online if anyone else is interested in this stuff.

I borrowed a field mill meter at my university (made by the Phywe
company), and made some interesting measurements of weak electrostatic
machines with it:
http://www.coe.ufrj.br/~acmq/bohnenberger.html
http://www.coe.ufrj.br/~acmq/bennet.html
It's very sensitive, being able to detect a few volts a meter away, and
has a computer connection that is convenient for more complex
measurements.
For those measurements, I used it as a high-impedance voltmeter, using
an attachment that is just a plate in front of the rotating vanes.
The instrument is not very robust, however. I have two to repair after
someone connected the power supply input to the meter output...

Antonio Carlos M. de Queiroz