[sdiy] sniffing

[Grant Richter]

Just use a CA3140 in a non-inverting gain configuration of 1000. Use 10 x 10
meg resistors (100 megs) as the bias supply to the + terminal and current to
voltage converter for the EM field. You can power the CA3140 off of two 9
volt batteries for an isolated supply.

Look around on the net for "electrometers" "lightning detectors" or "charged
cloud detectors". Fun stuff.

I used the exact circuit to build and alpha particle detector for an "Atomic
Source of Uncertainty", then 9/11 happened and obscure mathematical
explorations seemed rather irrelevant...

Mores the pity, as nothing has really changed, except me.


> From: "Czech Martin" <Martin.Czech at Micronas.com>
> Date: Tue, 15 Apr 2003 10:06:55 +0200
> To: "Magnus Danielson" <cfmd at swipnet.se>
> Cc: <synth-diy at dropmix.xs4all.nl>
> Subject: [sdiy] sniffing
> 
> As a magnetic field probe I just used a roll of isolated wire (cord),
> about 20 loops. In the way this wire is sold, I had simply to cnnect the ends.
> 
> Perhaps for higher frequencies only one loop would be better.
> 
> But how can you build a low cost E field probe?
> 
> Perhaps an aluminum ball? Where goes ground in this case?
> Or two balls forming a dipole?
> Perhaps a jfet could be used to buffer the high impedance in this case?
> 
> 
> m.c.
> 
>