1

I was wondering what would happen to capacitance if the plates are not parallel (above/below each other) or if the plates are not the same size. Thanks.

321
  • 13
  • Kindly make use of Google – pho Feb 11 '14 at 04:02
  • Yeah that hasn't helped. I've checked... – 321 Feb 11 '14 at 04:05
  • Generally, if the assumptions underlying the derivation of a formula do not hold, e.g.., the formula for the capacitance of a parallel plate capacitor, there is no reason to expect the formula will be applicable. In other words, the answer to you question of what "would happen to capacitance" is: it would be different from the case that the plates were parallel and of the same size. – Alfred Centauri Feb 11 '14 at 04:07
  • Do this and this and this help? If yes, and I strongly suspect they should, they were the first three Google results for "non parallel capacitor" – pho Feb 11 '14 at 04:09
  • I figured that too but how do they differ? Does capacitance increase or decrease? and why do the plates not being parallel or not being the same size have this effect? – 321 Feb 11 '14 at 04:10
  • Thanks pranav. I'm taking a look right now to see if they help. Guess I need to type my searches better. – 321 Feb 11 '14 at 04:12

1 Answers1

1

Okay, here's a simple explanation:

You can consider a non-parallel plate capacitor as multiple parallel plate conductors, connected in parallel, with the distance between them increasing slightly for each capacitor.

You get the net capacitance as the average of the minimum capacitance (based on the minimum distance b/w the plates) and maximum capcitance (based on the maximum distance b/w the plates) if the plates are flat. If they aren't flat, you need to integrate over the surface of the plates.

pho
  • 4,605
  • Thanks. Also for my second question would the answer be that the capacitance depends on the smaller plate? This is what I'm getting from searching google. But I don't quite understand why this is the case... – 321 Feb 11 '14 at 04:50
  • Yes. Because there isn't an "opposite plate" to the extra bit – pho Feb 11 '14 at 04:51