Re: S.s. info...re: differing secondaries

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

Original poster: "Kennan C Herrick by way of Terry Fritz <twftesla-at-uswest-dot-net>" <kcha1-at-juno-dot-com>

Hi Richie-
 
comments from KCH interspersed...
 
On Sat, 17 Feb 2001 15:22:04 -0700 "Tesla list"
<<mailto:tesla-at-pupman-dot-com>tesla-at-pupman-dot-com> writes:
> Original poster: "R.E.Burnett by way of Terry Fritz 
> <<mailto:twftesla-at-uswest-dot-net>twftesla-at-uswest-dot-net>"
<<mailto:R.E.Burnett-at-newcastle.ac.uk>R.E.Burnett-at-newcastle.ac.uk>
> 
> 
> Hi Ken,
> 
> Thanks for putting our minds at rest ;-)
> 
> I was going to post you a question asking how you ensure that your 
> driver
> locks on to the "Fundamental" of your resonator and not one of the 
> higher
> "Harmonics" of the resonator.
> 
> I guess your phase adjustment circuit performs a similar function to 
> the
> tuned grid used by the tube guys ???   Does this ensure that the
> oscillator does not accidentally start at 3xF instead of the 
> fundamental
> frequency ???
 
My phase adjustment has merely been a 0.15 uF capacitor to ground through which
the secondary current flows (with back-to-back diodes across it to limit the
voltage).  Following that, a few stages of linearly-configured CMOS logic ICs
for amplification, leading to the gated MOSFET-driving circuits.
 
But I have found, just today, that I seem not to have enough amplification when
using my 36" coil.  So I have to re-work that part of the circuit; and at the
same time, try to figure out a better, variable, phase-adjusting scheme to
accomodate various secondaries.

> 
> Sorry for all the questions,  but I'm thinking of converting my SSTC 
> so
> that it uses the primary current as the reference to switch the 
> FETs.
 
Do you not mean secondary current?  You'd want the secondary's Fr to be the
determinant of operating frequency.
> 
>                                                         Cheers,
> 
>                                                         -Richie 
> Burnett,
> 
> > Original poster: "Kennan C Herrick by way of Terry Fritz
> <<mailto:twftesla-at-uswest-dot-net>twftesla-at-uswest-dot-net>"
<<mailto:kcha1-at-juno-dot-com>kcha1-at-juno-dot-com>
> > 
> > To John Freau, R. E. Burnett et al:
> > 
> > Big dummy that I am, I neglected to realize that I had to adjust 
> the
> > phase angle of the signal I pick off the secondary for excitation 
> of the
> > primary circuit.  Just now, temporarily substituting a sig. gen. 
> output
> > for that signal, I find that my 36" space-wound coil does indeed 
> seem to
> > function at least as well as the 52" one.  I'll still construct 
> the
> > close-wound 36" coil (more like 32" if I can only get a 10# wire 
> spool)
> > so as to compare that to the others.
> > 
> > Next task is to incorporate a selectable-phase-shift circuit so as 
> to
> > accomodate various secondaries conveniently.  It just goes on & 
> on.
> > 
> > More later...
> > 
> > KCH
> > ________________________________________________________________
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> > 
> > 
> 
> 
> 
>