Re: TC Secondary Currents - was ( Experimental Help - Terry?)

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

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

Tesla list wrote:
> 
> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jimlux-at-earthlink-dot-net>

> The real problem is that c^2 proportionality constant.  It takes a HUGE
> change in electric field going very fast (in my case, a spark gap discharged
> the cap) to produce a very small magnetic field, which is tough to detect in
> the presence of all that changing E field.

Proportionality constant? The magnetic field produced by the
displacement
current should be the same produced by an equal "real" current. If this
is the case, you don't need more than a few mA to have something clearly
observable (5 mA in a wire are enough for Oersted experiment, with a
sensitive compass). 

The main problem is to separate the magnetic field caused by currents
in the capacitor plates and wiring from the field caused by the 
displacement current.

There are some sites in the web, from university laboratories, showing
measurement setups for displacement current. The ones that I have seen
don't appear to be much careful about this...

I am thinking about the following: Make a capacitor from two large metal
disks, and connect AC from a signal generator to it through a coaxial
cable, at one side of the assembly. Try then to detect a magnetic field
at the edge of the capacitor, exactly at the other side, using a probe
coil, maybe behind a grounded metal plate for electrostatic shielding. 
With this setup any magnetic field caused by currents in the capacitor 
and wiring will be cancelled or be in the wrong direction. Any magnetic 
field oriented along the circunference of the disk must be due to 
"displacement current".

A Wimshurst machine charging the capacitor would probably cause too
much interference for a precise measurement. A spark discharge can
easily induce hundreds of volts in everything around...

Antonio Carlos M. de Queiroz