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If you put more surface area inside of a leyden jar.... will the layden jar be able to store more electricity??? Answered

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steveastrouk (author)2009-10-13

Only if you have a bigger jar. Capacitance= Permittivity x (Area of plates)/ (gap between plates)<br /><br />Steve<br />

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kelseymh (author)steveastrouk2009-10-13

The counterintuitive relationship with dielectric thickness is interesting, isn't it?  You reallly want to nest a jars together, or make a jelly-roll. 

Hmmmm....I wonder whether waxed paper has a high enough breakdown voltage to support being used that way.

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Kiteman (author)kelseymh2009-10-13

Weren't some early capacitors made with wax paper?

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kelseymh (author)Kiteman2009-10-13

Yes, but my memory was that was more like thin cardboard soaked through with parafin.  I'm curious about the consumer stuff you can buy at the market.

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Kiteman (author)kelseymh2009-10-13

I've toyed with the idea of strips of kitchen foil, rolled between strips of plastic grocery bag...

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steveastrouk (author)Kiteman2009-10-13

Apart from the fact you might be able to scrounge some pF WHY ? 
;-)
Steve

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Kiteman (author)steveastrouk2009-10-13

Personal satisfaction?

To prove I can?

Fun?

To understand capacitors better?

Do I need a reason?

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steveastrouk (author)Kiteman2009-10-13

Try two pieces of PCB material. Rub top one vigorously for a few seconds with a dry cloth. Hand resulting sandwich to unwitting assistant, and ask them to separate the boards - did this to my wife by accident.

Yes, I think you need a reason to do anything.

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user

Yeah. But your reason doesn't have to be important, or sensible. WEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE!

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V-Man737 (author)steveastrouk2009-10-14

I've not found salvage capacitors with a high voltage. Homemade Leydenjars handle it beautifully. Sure, their capacity is tiny, but NikolaTesla made all of his capacitance experiments with jars, and that says alot about their utility to me.

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steveastrouk (author)V-Man7372009-10-15

Tesla would have had no choice. Modern capacitor tech is amazing. You'vefound the problem, you want lots of capacitance and a jar ain't hackingit.

I'll no doubt have people reminding me of the "deadly" mercuryin a fluorescent tube, but the glass in a tube is very thin, and you'dprobably gain a hell of a lot from the 1/D relationship. Intimatelycoating the inside and outside of the jar with the plates would helptoo. Colloidal graphite "Aquadag" if you can still get it,would let you make a conductive surface.

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user

What is permittivity? Is it when girls wear less at school?

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Sorry, dumb joke, I really am curious though.

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Its a magic number that makes the maths work....Its a quality ofthe materials you use for the dielectric basically, the lowest you canhave is the "permittivity of free space" <br />http://en.wikipedia.org/wiki/Permittivity is pretty authoritative.<br /><br />Steve<br />

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<a href="http://en.wikipedia.org/wiki/Permittivity">Permittivity</a> (for convenience)<br />Wow.<br />So there isn't a direct way to measure it (no mult-meter setting you can use)?<br /><br />

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