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Re: what IS a capacitor anyhow



Subject: what IS a capacitor anyhow?

On 19 Feb 1998 22:57:25 -0800 (PST) William Beaty used this picture in his
intersting message. I never saw this kind of discussion. Thanks for sharing.

___--- ---___ +++
| || | ++++++ 12 pos
| || | <--- ++++++ charges
| || | +++
| || |
A | || | B
|___ || ___|
--- ---

One way to implement this would be to bombard the plate B with alpha
particles.
+ +
+___--- ---___ +
/ -||+ \ Half of the (+) particles on B
+| -||+ |+ dive into the gap, but they induce
| -||+ | charges of identical polarity
+| -||+ | to appear on the OUTER surface of
| -||+ |+ hemisphere A
+\___ -||+ ___/
--- --- +
A + + B

We put no charges on hemisphere A, yet as far as the world outside the
narrow gap is concerned, A is now charged. The narrow gap makes A and B
interact strongly. It SEEMS as though there has been a current between A
and B. This "current" caused half of our 12 positive charges to travel to
the OUTER SURFACE of A. They didn't jump the gap. This wasn't an
electric current, but the end result is almost exactly the same as if
charges had crossed the gap. To a first approximation, charge has
flowed THROUGH the capacitor.

So, see why "Displacement Current" is not easily removed from capacitor
explanations? ......