Re: 3/4 wavelength secondaries
Tesla List wrote:
> >From rwstephens-at-ptbo.igs-dot-netTue Jul 23 21:47:18 1996
> Date: Tue, 23 Jul 1996 15:23:28 -0500
> From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
> To: tesla-at-pupman-dot-com
> Subject: Re: 3/4 wavelength secondaries
> >>From MALCOLM-at-directorate.wnp.ac.nzSun Jul 21 22:11:11 1996
> >Date: Mon, 22 Jul 1996 08:34:11 +1200
> >From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> >To: tesla-at-pupman-dot-com
> >Subject: Re: 3/4 wavelength secondaries
> Malcolm wrote,
> >Hi all,
> > This from Robert caught my eye....
> >> There are no physical restrictions that I am aware of that would
> >> ever prevent one from winding a secondary that was the entire 90
> >> electrical degrees (1/4 wavelength) in length and resonating it
> >> without any sort of topload to a given Tesla coil system.
> >I'd be grateful to any body who produces data for a terminal-less
> >coil that can do this.
> If you can calculate the isotropic capacitance represented by a
> 1/4-20 bolt about 2 inches long that might be used as a coil top
> terminal as I gave in one of my examples, and then determine how much this
> isotropic capacitance will 'pull' the resonant frequency of a 100 KHz
> Tesla secondary, then I'll gladly have no objection to your refering to it as a
> Top Load!:)
> Happy Coiling!, with or without the donut, rwstephens
I must note that there is probably a lot of semantics here.
If one is talking about the classic formula for a quarter wave wire
length based on frequency and the speed of light, then it will forever be
physically impossible to wind that length of wire into a coil and
resonate at the specified resonant frequency!
It is possible to wind a coil which, without any terminal whatsoever, can
have a quarter wave resonant frequency of virtually any frequency
Finally, any terminal load, even the bolt, will lower the output
frequency of any coil! The 100KHZ example given by Robert would be
affected so little as to not be worth discussing.
Richard Hull, TCBOR