I use two LEDs paralleled back-to-back in series with the signal generator
and the bottom of the secondary. Tune for the brightest response. This
has always got me going in the right direction.
On Fri, Apr 4, 2014 at 12:25 PM, Phil Tuck <pip@xxxxxxxxxxx> wrote:
> Jim wrote>>" The wire test is also pretty instructive in general"
>
> Defiantly!
> Just the presence of your own body (doing the test) in the area close to a
> bigger coil can cause a difference. Doing it on larger secondary's is best
> done with a long lead to avoid this. Low ceilings will affect things as
> well
> - hence JavaTC asking questions at the beginning, about the environment of
> the coil.
>
> Jim wrote>> "some egregious error like having the topload not connected to
> the secondary"
>
> Or scoping the primary without shorting the spark gap out? (cough)
>
> Phil
>
> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
> Of Jim Lux
> Sent: 04 April 2014 17:06
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Secondary Resonant Frequency test ??
>
> On 4/4/14 8:42 AM, Phil Tuck wrote:
> > Teslalabor wrote: "it is completely useless"
> >
> > No no, I wouldn't that!
> > True the streamers have a capacitance of a couple of pf / foot to
> > upset things, but the scope method gives a very good estimate and the
> > smaller the coil the more accurate it should be - less output, less
> effect.
> > You simply use the 'wire' method mentioned and then compare the
> > difference with and without the wire. I tune the primary around 8%
> > lower, (82 down to
> > 74 KHz approx)
> > Only trouble with the scope method is that you get harmonics show up
> > as well, so doing a sweep involves looking for the highest amongst the
> > several peaks that will occur. Using JavaTC beforehand will tell you
> > the figure reasonably accurately as a guide though, to avoid mistaking
> > a harmonic as the correct peak.
> > Phil
> >
>
> And to echo Phil, the other thing you can check for is some egregious error
> like having the topload not connected to the secondary. Oddly it sort of
> works, because the "sparkgap" at the top of the secondary connects it to
> the
> topload, sort of.
>
> (not that I'd ever have done that, no, never, uh-uh)
>
> measuring your secondary is also handy for other reasons: how many of us
> have tried increasing Csec by piling something else on top of the toroid
> (like another toroid, or a bucket, or a pumpkin, or an aluminum christmas
> tree).
>
>
> The wire test is also pretty instructive in general. You can see if moving
> stuff around your test area causes a "significant" change in resonant
> frequency.
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