What is the Equivalent Capacitance in This Circuit?

AI Thread Summary
The discussion focuses on calculating the equivalent capacitance of a circuit, with the final answer determined to be 4C/3. The user initially approached the problem by assuming symmetry, concluding that one capacitor had zero charge, and calculated the top and bottom branches separately. They applied the series and parallel capacitance formulas but encountered a mistake in their algebra. After correcting their calculations, they acknowledged the error and refined their approach to arrive at the correct answer. The conversation highlights the importance of careful analysis and verification in solving circuit problems.
Acuben
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Homework Statement



http://yfrog.com/mrcapdg

http://img819.imageshack.us/img819/1172/capd.th.gif

Find equivalent capacitance
answer is 4C/3

Homework Equations


whatever is in parenthesis is subscript
formula1: series: 1/C(eq)= 1/C(1) + 1/C(2) + 1/C(3) + ...
formula2: parallel: C(eq)=C(1)+C(2)+...

formula3: V=Q/C

The Attempt at a Solution



because of symmetry I decided that 3C has 0 charge (0q) and that top part has same voltage as the bottom part

charge split top and bottom equally

so I solved the problem "as if" 3C doesn't exist
so on the top series I get C/3 (using formula 1) and C/3 for bottom as well since it's in symmetry
and top and bottom form parallel so I get
2C/3 using formula 2

which is only half the answer

><
 
Last edited by a moderator:
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For top branch 1/Ceff = 1/C + 1/2C = ?
 
o thanks for pointing that out, I made simple algebra mistake ^^
 

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