Re: A new tuning idea?

["Steve" <Steve-at-g8cyerichmond.freeserve.co.uk> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

How about this as an alternative, it's used by radio hams for monitoring
earth current. Feed the lead through a ferrite ring. Wind a number of turns
of thin wire through the core to form a secondary. Connect a lowish value
resistor across this, and then measure the induced voltage using an analogue
ac voltmeter. I can't remember any values, but in any case it would depend a
lot on your particular coil. i only give this as an idea that might be worth
playing with, come to that I might have a go myself over the next few days.
Steve
----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, July 21, 2000 8:04 PM
Subject: Re: A new tuning idea?


> Original poster: Terry Fritz <twftesla-at-uswest-dot-net>
>
> Hi Gary,
>
> The secondary RMS current is around 350mA for a 15/60 coil.  At least it
> is for my big LTR coil but say 100-400mA should cover them all...
>
> John Courture's Tesla Coil Construction Guide describes this exact
> technique on pages 14-5 and 14-6.  He suggests a number 1891 lamp.  The
> resistance of the lamp is non-linear in this high current, low duty cycle
> use so calibration would be tricky but for basic qualitative tuning it
> works.  Perhpas a way could be found to calibrate it with some thought...
>
> I seem to remeber the "first" person to think of this was that guy from
> Croatia :-))
>
> Cheers,
>
> Terry
>
> At 08:56 AM 7/21/00 -0400, you wrote:
> >Several months ago I raised the possibility of metering the light output
> >from a fluorescent tube as a means of quantifying the output of a coil
for
> >tuning purposes.  I never actually tried this as further thought made me
> >think that varying streamer length and attachment would result in
variable
> >E-fields and unstable readings.
> >
> >Now I'm wondering if metering the secondary base current might provide a
> >more stable and indicative reading of "in-tune"-ness.  This might be
> >accomplished simply by inserting a small incandescent bulb in series with

> >the secondary base connection, and again using a photocell and analog ohm
> >meter to indicate the relative base current.  It would probably work best
to
> >provide a close target for the streamers so that they are essentially
> >continuous and the same length.
> >
> >Does anyone know what the RMS base current for a medium-sized (15/60 NST
> >powered) coil might be?
> >
> >Regards, Gary Lau
> >Waltham, MA USA
> >
>
>
>