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Making a capacitor

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Halibut

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I've got a question about making a capacitor. I'm thinking about using 2 sheets of alluminum foil and a few sheets of polyethylene (saran wrap) and then rolling it all up. My questions are:

1) Will this work, and if it does, what kind of voltage will I be able to charge it with?

2) How many sheets of the polyethylene should I use between sheets of aluminum foil, and will the number of sheets affect the maximum voltage?

I'm pretty sure I can get a high capacitance (almost limitless ammount of foil and saran wrap), but before I tried anything I figured I'd ask if anyone had any experience with this kind of thing.

Thanks in advance.
 

mattg2k4

New Member
You can google "party cup capacitor" and "salt water capacitor", both of those are common types of homemade caps. I've heard of your method, but never done any investigation of it. You'll have to use a lot of foil to get a very big capacitance. The homemade type of caps are generally capable of very high voltages, but lower capacitance because of imperfections in homemade construction, and thicker dielectric material.

The DC electronics volume of these books has a chapter on capacitors that will explain the factors affecting capacitors much better than I can. Even though saran wrap is pretty thin, it's still thicker than what you find in normal electolytic caps, and I'd guess would go in the hundreds and probably thousands of volts.

Since it'll be fairly easy to make, just make one and see what voltage blows it. Then use it at a lower voltage for general use.
 

Halibut

New Member
re

Thanks for the reply. I've seen the saltwater caps before, but I wanted to make something a little more portable. I'll look into the party cup idea. If I do decide to go with my original idea, I'll post the results. Prolly won't be for another week or so until I can fully test it though (multimeter is in the mail).
 
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