Re: resonant freq.

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

Original poster: "D.C. Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <DR.RESONANCE-at-next-wave-dot-net>


The distance does depend somewhat on the size (dia.) of the secondary coil.
Start back 2-3 feet and if you are not getting any signal on the scope as
you run the sig. gen through the estimated (1/4 lamba) freq. range, then
move the "antenna" a bit closer.  You don't want to overcouple the pickup
and load the sec. coil down in any way.

Regards,

Dr. Resonance



----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, July 11, 2002 7:00 AM
Subject: Re: resonant freq.


> Original poster: "Sean Taylor by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<taylorss-at-rose-hulman.edu>
>
> > No, nothing wrong.  Your technique is another valid and clever way of
> doing
> > it.  We just always used the "antenna" approach and it seems to work
well
> > for us.
>
> Ok, I thought it would work. . . does the antenna throw off the tuning of
> the coil? I guess it wouldn't anymore than being within a couple feet of
the
> coil would . . .
>
> Sean
>
>
> >
> > Best regards,
> >
> > Dr. Resonance
> >
> > ----- Original Message -----
> > From: "Tesla list" <tesla-at-pupman-dot-com>
> > To: <tesla-at-pupman-dot-com>
> > Sent: Wednesday, July 10, 2002 5:47 PM
> > Subject: Re: resonant freq.
> >
> >
> > > 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
> > > >