Re: Fiber Optic V & A Meters

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

Original poster: "Finn Hammer by way of Terry Fritz <twftesla-at-qwest-dot-net>" <f-h-at-c.dk>

hi Steve, all!

A couple of years ago, I arranged a group buy of the printed circuit
boards for the fiberprobes described below.
Some sort of access to the (at least) voltage waweforms, across the tank
cap, is necessary, to get _any_ idea about what is going on, really.
Without it, you are poking around in the dark.

Personally, when I saw the ringdown on my scope for the first time, I
went bananas, and called people around the globe, to share the
experience, it was _that_ great an experience to see, that the circuit
that sounded so frantic, was really producing such a benign looking well
controlled ringdown as seen on nmerous pictures on websites. But to see
it real life, was a _soother_. First then could I grasp that it was
_really_ happening.

Without it, (the probes) how could I confirm the Microsim predicted
equal bangsize charging behaviour at 300 bps:

Http://home5.inet.tele.dk/f-hammer/tesla/museum/setup/setup.htm

It is a bit pricey to complete the set, but it is the gateway to
certainty above speculation and and the like, so I still cannot see, how
to get along without them.

The problems with setting up a rotary, which is reported on the list so
often, could be avoided altogether, if there was accecc to a set of
fiberprobes.

Cheers, Fin Hammer

Tesla list wrote:
> 
> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> 
> Hi Steve,
> 
> See this file about fiber optically coupled probes.
> 
> http://hot-streamer-dot-com/TeslaCoils/Misc/Project_color.pdf
> 
> Beware some "cheap" fiber optics stuff has a very limited working distance.
>  Red LEDs don't go through plastic fiber well.  You usually need blue, IR
> or something like that to get to over a meter of fiber length with analog
> signals.  The glass fiber ones can go miles and really are worth the extra
> money.  But they are a lot extra...
> 
> Cheers,
> 
>         Terry
> 
> At 11:03 PM 8/24/2002 -0600, you wrote:
> >I like to measure KV and mA supplied by my filtered DC supply while it is
> >powering my twin TC.  The supply is plus & minus 10KV, center grounded (4
> >MOTs, twin doublers).  I now use analog meters directly wired into the HV
> >and have the meters located away from the coil so I can read them without
> >getting streamer zaps.
> >
> >I don't like the meters floating at high voltage - not safe.  I would like
> >them isolated by optical fiber cables.  If I use a simple LED and
> >phototransistor combination, or LED and photodiode and op amp, what
> >linearity can I expect?  I need to measure 0 to 20 KV and 0 to 200 mA.
> >
> >If any of you have built fiber isolated V & A meters, please share details
> >and results.
> >
> >Thanks,
> >--Steve Young
> >
> >