Re: Finally a Field Mill!

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

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


>Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><jimlux-at-earthlink-dot-net>
>
>Richard Hull (I believe.. it might have been Steve Roys) published a design
>for an electrostatic field probe of comparable sensitivity using some very
>very low leakage op-amps inside an appropriate shielded can, etc.
>
>The problem with field mills and op-amp field probes is their frequency
>response.   A TC is at 100 kHz, so I don't know that you could measure very
>well.
>
>However, you might be able to use a field mill type probe with a known DC
>voltage on the topload to generate a calibration curve for another sort of
>probe.  Somehow, you'd need to account for the field due to the secondary,
>though, and for DC you won't get the nice linear curve of voltage you
>want... (Maybe, run a wire up the center of the secondary to draw some
>current through the secondary (milliamps)...


Hi Jim,

I was actually thinking more of using it to measure the residual static 
field created by the coil since I didn't think it would work well on an 
operating coil for the reasons you mentioned.  The residual charge on the 
secondary and surrounding objects can be quite potent however, and I 
thought this would be fun to investigate.

Zap!

Charles Brush