RE: Need some capacitor help please

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com> 

Aside from the issue of the single dielectric layer being doomed to failure 
for use at 15kV, and assuming that your six poly sheets are actually 5 mils 
each, not microns, your formula does not take into account that except for 
the outermost pair, both sides of each plate are functional.  So, your 
formula should be C=k*A*2/d, C in pf, A in sq inches, and d in inches.  I 
calculate that you will need 15 plates to achieve .013uF.

Gary Lau
MA, USA


Original poster: "Philip Brinkman" <peeceebee-at-mindspring-dot-com>

I'm making a new stacked flat plate capacitor using sheets of aluminum foil
7.5"x9" trying to get 0.013 microfarads. Using the equation C=kA/d (k = 2
polyethyline) . I get 3.25 sq. meters, or 74 foil sheets, does this sound
right? My last capacitor had only 30 sheets. I'm using 6 layers of 5 micron
poly plastic between the sheets of aluminum.   Thanks, Phil B.