Re: resonant freq.

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

Original poster: "Sean Taylor by way of Terry Fritz <twftesla-at-qwest-dot-net>" <taylorss-at-rose-hulman.edu>

Is there something wrong with this method:

Inject a signal into the bottom of the secondary through a 1 KOhm
(about) resistor, and monitor the voltage at the bottom of the
secondary (after the resistor).  When this voltage goes to a minimum,
you have reached resonance, in other words, the voltage across the
resistor is at a maximum, thus current is at a maximum.  Am I missing
something here?  Thanks,
Sean Taylor



-------------------
> Original poster: "Malcolm Watts by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
> 
> Hi D.C.,
> 
> On 7 Jul 2002, at 12:49, Tesla list wrote:
> 
> > Original poster: "D.C. Cox by way of Terry Fritz
<twftesla-at-qwest-dot-net>"
> <DR.RESONANCE-at-next-wave-dot-net>
> > 
> > 
> > Inject a signal into the bottom of the secondary coil and then,
using a
> > scope probe, hold a small 4-5" long piece of wire near the top of
the coil's
> > toroid --- 1-2 in. away but NOT TOUCHING the sec. coil  This
antenna will
> > pick up the signal and give you the resonant freq on the scope. 
You could
> > also just use a 5 meg resistor between the scope probe and the
toroid.
> > 
> > The lowest freq you can find will be the resonance point.
> 
> I'd say that a couple of inches away from the terminal is far too 
> close to give an *accurate* figure (unless the coil is going to be 
> that close to something else while running) and 5MOhms is too much 
> loading. I suppose it depends how accurate you want to be. I
normally 
> won't have a probe closer than 3 feet (or more if I can get a 
> readable signal).
> 
> Regards,
> malcolm
> 
> 
> 
>