Re: Electrometer design (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 11 Jul 2004 12:21:54 -0500
From: Dr. Resonance <resonance@xxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Electrometer design (fwd)

A round sphere works even better.  We use a 14 inch Van de Graaff terminal.
The sphere acts like a capacitor, and due to it's larger surface area,
collects more charge.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
>
> Charles Brush wrote:
> > The design is incredibly simple.  Basically you have a little NE2
> > lamp in parallel with a capacitor with one side attached to ground
> > and the other to an elevated and sharply pointed rod.  As the local
> > field increases current will flow through the circuit causing the cap
> > to charge and periodically discharge through the NE2 causing it to
> > blink.  The faster it blinks the stronger the field overhead.  I
> > tried this a few summers ago but I can't remember the cap value I
> > used (anyone have suggestions?).
>
> This design (or one like it) is described in Iannini's "Building your own
> working fiberoptic infrared and laser space-age projects"  (the book with
the
> long-winded name).  The capacitor value is given as 1nF @ 1kV.  Fig 14-12
on
> page 238 in my copy.
>
> This uses a metal can instead of a pointed rod as a charge collector.
This sits
> on a plastic aerosol cap to insulate the can from ground.  NE2 shows
through a
> hole in the cap.
>
> Cheers
>
> M
>
> --
> Matthew Smith
> Kadina Business Consultancy
> South Australia
>
>
>