Re: Early versions of Tesla's coil

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

Original poster: "Ed Phillips by way of Terry Fritz <teslalist-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
 >
 > Original poster: "RMC by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
<RMC-at-richardcraven.plus-dot-com>
 >
 > Ed
 >
 >  >  > >As far as I know all of the "Tesla coil" leak
 >  >  > >detector spark coils operate in this way and are probably being built
 >  >  > >still.  I have one built by Rogers Electric in 1916 which works this
 > way
 >  >  > >and puts out about a 1" spark.
 >
 > I have a pair of these vacuum leak testers, both made by a British company
 > (Edwards High Vacuum, I think - they're not to hand at the moment). They are
 > wired as convential Tesla coils which I now describe. They are not induction
 > coil hybrids.
 >
 > Both are identical and use a primary of about 3 turns on a 1" diameter, 22
 > swg or similar. the secondary is conical and gives an excellent brush
 > discharge into free space. The spark gap is a large relay contact
 > arrangement - two facing W pads and a cam-shaped bakelite lever that presses
 > a phosphor-bronze element holding one of the faces towards the other.
 >
 > The primary cap is a couple of nF and the mains transformer is a
 > single-ended 2 or 3 kV output at a few mA.  It is a very small coil but is
 > very nice to see working.
 >
 > Cheers
 >
 > RMC, England

	That's interesting.  I haven't run across any of those or, if I did,
didn't recognize it.  Is most of it boxed?  Shat is the variable spacing
used for?

Ed