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[DPRG] mega caps

Subject: [DPRG] mega caps
From: Chuck McManis cmcmanis at mcmanis.com
Date: Thu Jan 28 14:17:52 CST 2010

Franklin, like others, used Leyden jars for his turkeycidal experiments. And
while its always possible to grab the latest super-cap from Sparkfun or what
not, building your own Leyden jars is both fun, and very impressive to folks
who haven't seen them before.

Like a modern capacitor, a Leyden jar can be charged by a power supply,
although its much more fun to charge them with "static" electricity. You can
also but a LOT of charge into a decent sized jar (say 6" in diameter and 15"
tall) enough to ionize air between the anode and the cathode causing self
discharges.

As for cooking a turkey, I think the analysis of the energy assumed *the
turkey* is the current limiting resistor (which is why it is cooking, its
"dissipating heat") If you have a turkey handy it would be useful to stick a
couple of forks in it and measure its resistance. I don't know how its
resistance would change over time but I do know one thing, if you used a
thousand 2.7v 1F capacitors (or 200 of the 5F ones) then the turkey wouldn't
cook at all because the current through it would be so small. (I'm guessing
a turkey, even brined, has a resistance over 1K ohms so 2.7v/1Kohms is only
2.7 mA of current. Or about 7 milliwatts of heat.

However if you used Leyden jars and static electricity you could get 2 - 5kV
potentials which have a much better shot at generating meaningful heat
dissipation.

If you do start building jars (easiest one is a Ball Canning jar with tin
foil shellac'd on the inside and outside and wooden plug instead of the
metal top. Be careful, they can look harmless but if you get enough charge
in one they can stop your heart. Always store / transport them with the
anode shorted to the outside of the jar. Unlike some things these things can
become charged by air blowing across them.

--Chuck

On Tue, Jan 26, 2010 at 12:16 PM, Randy M. Dumse <rmd at newmicros.com> wrote:

> DeltaGraph at aol.com said: Monday, January 25, 2010 1:00 PM
> > I think you could probably cook a turkey with that.
>
> Ron, I can't tell if you were inspired by the original event or
> not, so in case people don't get the connection, here's a link
> about the historical nature of cooking turkeys with electricity.
>
> http://www.timesonline.co.uk/tol/news/science/article3087946.ece
>
> Randy
>
>
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