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Re: Homemade stacked plate cap. *Need* a vacuum pump?




From: 	Jim Lux[SMTP:jimlux-at-earthlink-dot-net]
Sent: 	Monday, November 03, 1997 10:59 AM
To: 	Tesla List
Subject: 	Re: Homemade stacked plate cap.  *Need* a vacuum pump?


> Adam, unless you've already purchased the polyethylene, you may want to 
> look into plexiglass as a dialectric - it has double the dielectric 
> strength and a dielectric constant of slightly over 3, the big deciding 
> factor would be it's power factor - if it is greater than that of 
> polyethylene then it's a looser otherwise it may be cheaper and make a
more
> compact capacitor.

Polyethylene typically has a higher breakdown strength than acrylic
(Plexiglas) (800-1000 V/mil vs 300-400 V/mil). Also Plexiglas is very
lossy. Plexi does have good mechanical properties as does polycarbonate
(Lexan), which makes it handy for structural uses.  And, not the least, you
can glue plexi or polycarbonate, but nothing glues PE.