Re: 1/4 Wave, etc.

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: 1/4 Wave, etc.
From: Tesla List <tesla-at-stic-dot-net>
Date: Mon, 15 Sep 1997 23:44:20 -0500
Approved: tesla-at-stic-dot-net


From: 	Greg Leyh[SMTP:lod-at-pacbell-dot-net]
Sent: 	Monday, September 15, 1997 3:02 PM
To: 	Tesla List
Subject: 	Re: 1/4 Wave, etc.

Alfred A. Skrocki wrote:

> > It does not seem that the sec wire length makes an appreciable
> > difference in the performance of a standard TC.
> >
> > I have noticed in PSPICE that typical TC secondaries with even moderate
> > top loads do not exhibit any significant standing wave behavior, but
> > operate more as simple LC resonant circuits.  The voltage profile for
> > a normal TC along the sec is roughly linear, and only when the secondary
> > becomes coarsely space-wound with no top load does the voltage profile
> > start to bend into a quarter-sine.
> >
> > This explains why Richard Hull and others have discovered that more
> > top load is better, with no discernable correlation between the
> > operating frequency and the electrical length of the resonating coil.
> > -GL
> 
> Your observations are indeed correct! On can achieve effective 1/4
> wave length by loading a coil with capacitance, this is exactly what
> is done in many radio antennas to keep the antenna down to a
> manageable size. With simple Tesla Coils (not magnifiers) without the
> heavy top loading you will find that achieving both 1/4 wave length
> and resonance simultaneously will result in rather spectacular output
> for relatively small amount of input power.

As I was saying above, there appears to be little, if any, standing wave
action going on in TC's with large top electrodes.  Consequently, the 
issue of achieving both 1/4 wave length and resonance simultaneously
is moot, as there is a negligible standing quarter-wave component, IMO. 
The circuit is simply resonant.


-GL