BPS measurement, was Re: [TCML] Spark gap
yurtle_t at yahoo.com
Tue Feb 26 14:43:03 MST 2008
How about one of those fance storage CT's? I've never
seen one in action, and don't know the specs, but at
work, while trying to troubleshoot why something was
acting up, a number of small battery powered CT's were
used to measure a number of events. If I recall, the
things stored a lot of data. If it would work, you
could simply place it on the conductor leading from
the gap to the cap.
--- FIFTYGUY at aol.com wrote:
> In a message dated 2/25/08 9:48:00 P.M. Eastern
> Standard Time,
> bartb at classictesla.com writes:
> >Here is my very simple strategy:
> >* Hook up fiber cable near first gap to capture the
> light created by the
> >spark (where it will always issue).
> >* Convert light to DCV at opposite end.
> >* Record voltage output over 10 minute run.
> After my post, I gave it some thought.
> My criteria still are:
> *pocket sized
> *battery operated
> *direct display of BPS
> *works with vacuum tube, solid state, as well as
> spark gap coils
> *cheap and simple
> I'll add:
> *range from 100 to 1000 BPS
> *accuracy of +/- 5%
> I thought, as you did, that light from the gap
> might be a viable
> measurement point. But it would be difficult to get
> down near a gap on a running
> coil, and if you were too far from the gap you'd
> likely get interference from
> reflections and the secondary arcs.
> Besides, that wouldn't work on a vacuum tube or
> solid state coil.
> I figured the antenna method might be the most
> reliable. I drew up a
> very simple input end, which on further research
> turns out to be the standard AM
> detector circuit (no surprise!). This should turn
> the decaying sinusoid
> output into a pulse train.
> From there, I figured one could run it directly
> into a digital
> tachometer panel meter. But those things go for $50+
> new, and I don't have a spare
> sitting around. I looked at the digital photo tachs
> the model airplane hobbyists
> use for tuning engines. They run around $20. Maybe
> it would be easy to hack
> one (and even use for the basic project box!). Heck,
> they might even work
> as-is if you just point it at the gap.
> Or you could run the pulse train into a
> Freq-to-voltage converter chip,
> and drive an analog meter (but tough to keep 5%
> accuracy at the low end of
> the scale. Maybe not so important, as the 10x range
> would be handy enough?
> Or run the pulse train through the usual
> manipulations, and drive a
> 3-digit LED 7-segment display. Still cheap and
> simple, but tedious for me. I'm
> sure there's somebody here who would get some
> satisfaction from designing the
> simplest way to implement this. I was hoping Mr.
> Piranha would, since this
> would be right up his alley, and "Terry Tach" has a
> nice ring to it. ;)
> Wouldn't it be great to pull out a little gizmo
> at a Teslathon, and
> start comparing each other's breakrates? Yeah, it
> doesn't get geekier than that,
> but it would probably reveal a lot and allow for
> meaningful discussion
> without the usual speculation and hand-waving.
> -Phil LaBudde
> (yes, I own several oscilloscopes, but I'm lazy)
> Center for the Advanced Study of Ballistic
> **************Ideas to please picky eaters. Watch
> video on AOL Living.
> Tesla mailing list
> Tesla at www.pupman.com
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