From: William Noble[SMTP:William_B_Noble-at-msn-dot-com]
Sent: Saturday, August 02, 1997 10:45 PM
To: Tesla List
Subject: [rolled caps]
the general subject was arcover at the edges of a rolled cap.why not fuse the
edges together, or use wider poly and fold it - that way there is no opening
for the charge to get through. The other alternative that makes sense to me
is to make a bunch of "short fat" capacitors with the foil protruding from the
edges of the poly, then mash the foil down and press them end to end, putting
them in series.
The effect you note is an old one and is purely elecrostatic in nature.
Current will readily flow along differing dielectric boundry edges in the
presnce of rapidly changing voltage gradients. The sharper and more angular
they are the more likeily a flashover might occur. The classic example is
the plane, flat, dielectric surface with a knife edge lying flat on it
(plate and insulator sheet) Amazing arc lengths can be supported at
relatively low voltages provided the dv/dt is steep enough.
Richard Hull, TCBOR