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Lots of electrolytics...
----------
From: Jim Lux [SMTP:jimlux-at-earthlink-dot-net]
Sent: Friday, March 06, 1998 1:03 AM
To: Tesla List
Subject: Re: Lots of electrolytics...
>
>
> ----------
> From: Bill Lemieux [SMTP:gomez-at-netherworld-dot-com]
> Sent: Thursday, March 05, 1998 2:30 PM
> To: Tesla List
> Subject: Re: Lots of electrolytics...
>
> Tesla List wrote:
> > I believe that you can use a strobe flash tube as sort of a thyratron
to
> > switch power from your electrolytic capacitor bank.
>
> Well yes, for smaller currents, but flashtubes have a rather high
> on-resistance.
> Run the voltage up to overcome this, and you will probably see it
> shatter.
> They don't like very fast turn-on times. EG&G used to have a free
> "Flash Tube
> Design Guide" that covered the safe operating area of flashtubes.
They still do.. Call up the electrooptics division in Salem MA
(800)950-3441 and ask for the Linear Flashlamps brochure. While you are at
it, ask for the High Energy Switches and Electro Explosive Devices
brochure.
The ultimate reference, cheap at the $17 price, is Edgerton's book:
Electronic Flash, Strobe from MIT press...
> > The Radio Shack
> > xenon flash tube 272-1145 may work but is listed as a 4 watt-sec
maximum
> > flash energy. Anode voltage is from 200 - 400 V. Trigger voltage is
4kV.
>
> Trigger voltage of any spark gap-type switch (including thyratrons,
> trigatrons,
> flashtubes, etc) should always be >/= 10X the voltage across the switch
> for
> low jitter (repeatable turn-on time) operation.
And, a real fast rise time on the trigger pulse helps too....
>
> > If you do try this method, please let us
> > know what the extreme maximum flash energy possible with the Radio
Shack
> > flash tube is. You may be able to trade higher flash energy for lower
life
> > cycles.
There is some info on the web (do an alta vista search for strobes) about
the empirically determined max energy for the radio shack flash tubes. I
can't recall where it is though.
>
> Absolutely. I bet the RadShak flashtube would switch 100 watt-seconds...
> once.
I've switched 50 Joules with the Radio Shack tube and had a life time of
100's of flashes. Forced air cooling and low rep rate though (the
electrodes sputter onto the walls and the seals soften). 4 Joules is a
pretty conservative rating for that tube assuming it is firing at 60 Hz, I
think. I've even had the strobe circuit not quench and make a low power
xenon arc lamp (does get the series R in the charging circuit get hot
though...).