Flat Primary Winding - next question

From:  Jim Lux [SMTP:James.P.Lux-at-jpl.nasa.gov]
Sent:  Tuesday, June 16, 1998 10:13 AM
To:  Tesla List
Subject:  Re: Flat Primary Winding - next question

Clay Wilson on Tesla List wrote:
>         Remove the secondary (as I'm sure one might not wish to get zapped with
> the output from some TC's - or, at least for sure, the dreaded warthog <g>).
> Then, just fire up the primary circuit and let it go.  Get a piece of paper
> covered with ferric dust, start at a height corresponding to the height of the
> sec'y, and see if the dust is perturbed.  Move down slowly.....
>         Of course, this might not do anything, as most coils, from what I've
> read, seem to operate at frequencies in the ~50-60 to 300 kHz range, and such
> high frequency oscillations may have no effect, even on ferrite *dust*, at
> least until you get into relatively higher field values.
>         I guess a wire with a milliammeter on it would accomplish the same thing
> more reliably...

You'd want an RF mA meter (a loop with some 1N34's, perhaps).  However,
the magnetic field induced in the secondary has a pretty significant
effect on the overall field, so you'd want to leave it in place, and
then use a LONG insulated non magnetic rod to move your probe around. 
You could run at low powers, but the breakout of sparks from the upper
electrode has a significant effect on the coil functioning, hence the
suggestion of the long rod.

TO be really clever, use the Faraday rotation effect to measure the
field.  Too bad the fields are pretty small.