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Re: Found an oscilloscope and was wondering how I could ...
--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Malcolm Watts"
> <M.J.Watts-at-massey.ac.nz>
>
> Hi all,
> this post makes me wonder - would it be a
> useful idea
> for measuring a coil's breakrate to check the
> flicker rate in
> a fluoro tube using a photo transistor (destructive
> voltages
> aside)? I know there is some persistence in the
> tube. I might
> have a go at this on my coil. A crude scope test
> suggests the
> coil is intermittently operating at 100 and
> sometimes 200 BPS.
> It has a static gap. Any thoughts?
>
> Regards,
> Malcolm
>
Take a plexiglass clipboard sandwiched with aluminum
foil and more poly underneath, in a safe isolated area
away from ground. Attach this to one end of the
primary arc gap.{By using that as a sensing method we
are of course altering the operating conditions of the
coil to a small degree, a preliminary test of merely
placing the inductor near the arc gap might serve to
show spikes at 2ms/div sweep rates where those spikes
correspond to the BPS rate.} Place a small inductor on
this plate and route directly to scope. I dont know
if that technique would work on a tesla coil because
of secondary interference. I used it on large
induction coils in a self quenching arc gap as shown
in Hillbilly Scope pictures;
http://msnhomepages.talkcity-dot-com/LaGrangeLn/teslafy/anomolous.html
This shows a very large BPS rate that easily goes out,
corresponding also to the miscule gap used to produce
that effect. By turning down the sweep rate of the
scope to smaller time intervals it is also possible to
see the frequency of the ring, although this may also
appear as uncohered signals in scope observations,
showing rapid drift. If the information looks like
nonscense at higher frequency selection rates, {Using
the camera technique will produce anomalous
interference effects at 5 and 2 ms as the web page
shows, but a way to partilly eliminate this has been
found by reducing the intensity, in turn stabilizing
the drift on some observations made at that freq sweep
rate.}the scope can be taped from a VHS camera, and
then individual pause frames selected to see on tape
replay the rapidly drifting oscillation sometimes
found in smaller time intervals of examination
obtained by using a shorter time period for the sweep
time to peek at the actual high frequency process., ie
to find that frequency if it initially appears as
uncohered information. However the Heath 4221 scope
also contains a sensing option known as TV Coupling
that enables many of these drifting high frequency
signals to be cohered... The Hillbilly scope
picture was so named by the way it was made, by taking
a digital picture of a vhs replay of scope higher
sweep rates showing the ring with the digital
picture taken right in front of the television
screen,of the ring made at a higher frequency sweep.
In the case of my testing I found that each test
inductor would ring at its own resonant freq, this
might be a possible try for a tesla primary arc gap to
see if the same effect holds. Just a reminder for Ohio
Teslathon antendees to bring any small inductors over
one hundred ft wire length and any extra scope probes
so that possible scope monitoring of this sort can be
tried. Large open loop coils, of pancake sytle appear
to be good for monitors of this sort as the ring isnt
so high of a freq. (in what I have seen so far). I
have 5 scopes but only 2 probes. Event is on for Sept
16th, third Saturday of September. I also am eager to
see if the large induction coil high frequency
process can also be used to find a self resonant
frequency of a of a tesla coil secondary by direct
scope observation, and how adding a top load changes
that aspect.
Sincerely HDN
=====
Binary Resonant Systemhttp://www.insidetheweb-dot-com/mbs.cgi/mb124201
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