Re: Copper tubing

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

Original poster: "davep by way of Terry Fritz <twftesla-at-uswest-dot-net>" <davep-at-quik-dot-com>

(old matter)

Tesla list wrote:

> Original poster: "Mike Harrison by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <mike-at-whitewing.co.uk>

> On Thu, 12 Apr 2001 08:05:16 -0600, you wrote:
 
> >Original poster: "James Lewis Nance by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <jlnance-at-intrex-dot-net>

> >On Wed, Apr 11, 2001 at 06:16:56PM -0600, Tesla list wrote:
> >> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> ><A123X-at-aol-dot-com>

> >> If the high frequency electricity travels on the outer surface of
>>> conductors then does it travel on the outside surface of copper pipe,

	Mostly on the outside.

>>> and the inside surface?

	Mostly on the outside.

> >Just the outside surface.

	There is a small penetration, getting smaller as freq goes
	up.

> ..but surely the 'inner' surface is actually part of the outer surface
> of the _body_ of copper. How does the current 'know' which side of the
> wall it is on, unless the ends are electrically closed?

	Picture the 'current' as a 'gas' of electrons.
	All are negatively charged.  They try to get as far away from
	each other as possible.
	(Like all analogies, this is approximate.  But its REAL
	close....).
 
> Consider a flat strip - presumably current flows on both surfaces. Now
> bend it longditudally into a tube - how does current know not to flow
> on what is now the inside of a tube ?

	cf above....
	Put another way, the inside chokes off the efield, so there
	is nothing to drive current flow on the inside...

	best
	dwp