RE: Stop the nonsense

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

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-compaq-dot-com>

Regarding the assertion that a DC charge necessarily grows on the toroid in
advance of streamers, this just isn't possible.  Don't forget, the base of
the secondary coil is tied to ground.  It's not possible for one end of a
coil to be at ground and the other end to be at some DC potential relative
to the grounded end.  If the DC resistance of a secondary coil is 100 Ohms
and Csec is 50 pF, the RC time constant will be only 5 nsec, and any DC
charge would be dissipated long before it can accumulate.

A Van de Graaf generator is a DC machine, and its "top load" clearly
charges in a DC manner.  If you tried to tie the top of a secondary coil to
the VDG top load with the other end of the secondary grounded, it would be
a pretty uneventful show, discharging the top load faster than any charge
could accumulate.

I'm not sure why you feel that a toroid is a waste of time if it is AC-fed,
as most would suggest.  We want the majority of the secondary C to be in
the top load, Ctop, rather than in the isotropic capacitance of the
secondary, Cself, and this is why large top load coils seem to perform
better than small top load coils..  This allows a direct path for this
energy to feed a streamer, rather than having secondary inductance between
Cself and the streamer.

Do not confuse the static charge that is left on the secondary form surface
with anything that occurs on the top load.  The static charge on the form
and other insulated surfaces has been discussed at great length on this
list and is due to coronal rectification.  But this is just a side effect
and has no known effect on what goes on with the top load or streamers.

Gary Lau
MA, USA

 -----Original Message-----
From: 	Tesla list [mailto:tesla-at-pupman-dot-com] 
Sent:	Friday, February 15, 2002 2:05 PM
To:	tesla-at-pupman-dot-com
Subject:	Re: Stop the nonsense

Original poster: "rheidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<rheidlebaugh-at-zialink-dot-com>

A tesla coil is not a simple oscilator with contiouous AC power. It is a
pulse fed circuit. That is why a charge builds up on the toroid. If the
drive was pure AC of a balanced sign wave the use of a toroid would be a
waste of time.If you have an unbalanced + pulse a charge will build up on a
"ststic" charged surface and will grow with each pulse, just like a
VANDEGRAPH charging a sphere.an antenna sencing the wave shape using a scope
dosent see the DC part of the build up. You must use a space charge mesuring
detector to read the total charge. I don't hear anyone trying to measure
this level. Time after time I see postings of streamer size, but no one
measures the voltage of the static charge required to make that streamer. I
only see "OH goody Oh goody I got a big streamer".You get a sreamer when the
AC builds up a DC component to a point that the air breakes down and the
total AC & DC fires through the space of your play area.That is why most
TUBE tc are less impressive.Yes total power is less, But pure AC dose not
build up a charge.There must be a DC component to build a charge.BOTH !!!