Re: Fanciful spark-augmenter

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

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

[see end]

On Thu, 31 May 2001 13:16:46 -0600 "Tesla list" <tesla-at-pupman-dot-com>
writes:
> Original poster: "Ed Phillips by way of Terry Fritz 
> <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>
> 
> Tesla list wrote:
> > 
> > Original poster: "Kennan C Herrick by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <kcha1-at-juno-dot-com>
> > 
> > In my interchange with Scott Fulks yesterday on the subject, 
> there
> > remained a question about the Q of my fanciful apparatus.  I made 
> a quick
> > measurement today:
> > 
> > I wound 5T of 12 ga house-wire around a 12" dia form, connected a 
> fixed
> > capacitor across it, excited it with a 1T loosely-coupled coil 
> from a
> > signal generator, and measured its Q using the Fr/(F(hi)-F(lo)) 
> formula.
> > With a .03 uF capacitor the Q was ~18 and with a .07 uF one, 16:
> > essentially the same.
> > 
> > Not too near the Q of a good secondary, to be sure, but maybe 
> good
> > enough.  If excited with--say--my primary where I develop perhaps 
> 300
> > volts/turn of equivalent conductor, I should think I could pump up 
> such a
> > resonant tank to perhaps 3000 volts/turn.  At 5 turns, I would get 
> 15 KV.
> >  That's a fairly respectable capacitor-charge that subsequently 
> might be
> > dumped into the secondary at the slightly-shifted Fr.
> > 
> > Ken Herrick
> 
>         Something sounds very wrong with those measurements.  Can't 
> imagine
> such a low Q unless there was something wrong with the capacitors.   
> You
> didn't give the length of the primary, but assuming it was of the 
> order
> of an inch or so the inductance should be of the order of 12 uH.  
> That
> would give a resonant frequency around 264 kHz for the 0.03 ufd
> capacitor and 174 kHz for the 0.07; what did you get?.  I'd expect a 
> Q
> of well over a hundred in both cases.  Instead of coupling through 
> the
> second coil, why don't you try connecting the signal generator to 
> the
> primary/capacitor in parallel through perhaps a 10 k resistor and 
> repeat
> the measurement?
> 
> Ed
> 
Those freq's were about what I got, and the coil length was about that. 
I'd have thought to see a higher Q also; my technique was really Q&D,
though, so that might account for the discrepancy.  I'm encouraged that
you'd expect a higher Q since that would only, obviously, make the ckt
work better.

But see my other posting of today for an improved notion.

Ken Herrick
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