Re: Ground current experiments

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

Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Jon Rosenstiel wrote:
> The experiment worked beautifully!

Great.  Now there are two ways that the receiver (rx) coil can be
excited.  
 a) Capacitive coupling from the transmitting (tx) coil: Displacement
currents from the tx coil intercept the rx coil and stir up a
conduction current.  The shared ground-plane forms the return path
for these currents.
 b) Magnetic coupling:  The mag field from the tx coil induces an EMF
in the rx coil.

You should be able to distinguish between these two. Eg:
1) split the ground plane into two.  Ensure that each ground is
conductively and capacitively isolated from the other.  
2) Interpose an electrostatic screen between tx and rx. 
3) turn the rx coil on its side to minimise the B field coupling, but
leaving its topload undisturbed.

Also, split the groundplane so that the rx groundplane is floating,
and reconnect it to the tx groundplane via an AC ammeter. Measure the
current, which will equal the coupled displacement current, if any.
At the same time measure the tx coil base current.  The ratio of the
two currents gives you a coupling coefficient.  How does this vary
with distance?

Lots of interesting stuff to do now that you can reliably demonstrate
two coupled coils.  Nice work.
--
Paul Nicholson
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