Non-parallel plate capacitance

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SUMMARY

The discussion focuses on calculating the capacitance of a non-parallel plate capacitor, specifically where the separation at one edge is d-a and the other is d+a, under the assumption that a is much smaller than d. The goal is to prove that the capacitance C can be expressed as C = ε₀ A/d (1 + a²/3d²). Key equations include the distance between the plates, x = d + ay/L, and the integration of voltage V over the varying distance from y = -L/2 to +L/2, which involves expanding the logarithm.

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ianmc7
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Im having trouble calculating the capacitance of a non-parallel plate capacitor where separation at one edge is d-a and the other it is d+a, assuming a<<d. I'm supposed to prove that C= epsilon_not A/d (1+a^2/3d^2). Thanks for the help.
 
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The equations for the distance between the plates is x=d+ay/L.
The surface charge ~V/x.
Integrate V/(d+ay/L) from y=-L/2 to +L/2.
Expand the logarithm.
 

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