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Registered Member #3637
Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068
Hey guys. Just experimented with some anti static bags I had lying around. I had looked up what they were made of, metallic film, which is a type of capacitor. So, I quickly made a capacitor using cut sheets of anti static bags and aluminum foil. I got a 100 pF cap from roughly 7 or so layers. Not bad huh, especially considering I made this at 11 O' clock in kind of a mess.
Registered Member #3637
Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068
I knew you can make caps out of plastic sheets and stuff, but this was just a sort of "reuse and recycle" dealio here. It just kinda fascinated me that it worked.
Registered Member #1225
Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253
Inducktion wrote ...
I knew you can make caps out of plastic sheets and stuff, but this was just a sort of "reuse and recycle" dealio here. It just kinda fascinated me that it worked.
I know what you mean. As a matter of fact, plastic plate dielectric caps have proven to be pretty good. Each layer insulates a few tens of KV, and each are around 1nf each. Read this thread, they could be used as pulse caps if you really wanted, and stacked caps have low ESR and ESL
If you want a big homemade cap for Tesla coil duty, buy some polyethylene plastic in the paint section at a home improvement store. It is around 4 mils thick, 4 layers should be fine for at least 10KVAC, right?
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Arcstarter wrote ...
If you want a big homemade cap for Tesla coil duty, buy some polyethylene plastic in the paint section at a home improvement store. It is around 4 mils thick, 4 layers should be fine for at least 10KVAC, right?
4 layers of 4 mils is 16 mils, which if you use the 500V per mil number, I get 8000Vac. Of course these things always need to be tested. Like with a MOT and thin plates, then see what the punch through is.
Remember (for solids):
--dielectric strength increases with the increase in thickness of the insulant. (Directly proportional) --dielectric strength decreases with the increase in operating temperature. (Inversely proportional) --dielectric strength decreases with the increase in frequency. (Inversely proportional) --dielectric strength decreases with the increase in humidity. (Inversely proportional)
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Homemade caps...
