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RE: Elementary Lecture





> ----------
> From: 	Tesla List[SMTP:tesla-at-pupman-dot-com]
> Sent: 	Wednesday, February 24, 1999 11:08PM
> To: 	tesla-at-pupman-dot-com
> Subject: 	Re: Elementary Lecture
> 
> Original Poster: Brandywine <brandywine-at-writeme-dot-com> 
> 
>    Why sparks will leap between the toroid and a grounded object is quite
> understandable; but the magic of a Tesla coil is that sparks spontaneously
> branch
> out into thin air, connecting with seemingly nothing.
>    Consider 2 devices: A million volt Tesla Coil, and a million volt 60 Hz
> transformer. The TC will emit a discharge into the air that connects to
> nothing.
> We'll help the million volt xfmr by grounding one of the secondary HV
> terminals.
> Do sparks spontaneously emanate from the other HV terminal into thin air?
> No.
>    I certainly have not read all available Tesla coil theory, but I've yet
> to see
> a thorough explanation of why a Tesla Coil does what no other device can
> do--emit
> sparks that terminate in the air.
> Dave Hartwick
	>snip

Hi Dave, et al

I'm not sure of the best way to put this in elementary terms, but surely the
only way to understand why the H.F &H.V output from a TC has a greater 
propensity to produce a streaming discharge to air than that which comes of
an equivalent potential 60Hz terminal, is to understand isotropic capacity.

The isotropic capacity created by a Tesla coil terminal to the surrounding 
air, creates a much heavier load (lower impedance) at the coil's frequency
of say 250 KHz, than at the mains frequency of 60Hz.

If you replaced the air surrounding a 60 Hz terminal with a medium that
better matched it source impedance, then I'm sure you would have the same
effect.

I'm not sure what the dielectric constant of water is (very high!), but
surround the 60Hz terminal with that, and you may get the same effect! 
(though please dont try it!!)

Explaining principles we may know well in our own understanding, to others
in their understanding, is one of the most challenging things I can think
of!

A classic question I was once asked was "what exactly is a radio wave?"

Knowing what it is, and saying what it is are 2 completely different things!

    cheers,   Martin Dale   TCBON  Nottingham  UK 

ps, you will get a small amount of streamer output at 1MV 60Hz!