# How to solve these kind of electric circuit? [duplicate]

This question is an exact duplicate of:

This question from Physics For Scientists And Engineers 7th page 746. After redrawing , Actually I cant see any two clear capacitors that we can be combined , First we cant combine $$C$$1 with $$C$$2 because the point $$a$$, and the same argument on $$C$$3 with $$C$$4 because the point $$b$$, And personally I cant combine any of $$C$$1 ,$$C$$2 ,$$C$$3 and $$C$$4 with $$C$$3 because I don't know where should I put the equivalent capacitor.

To be more clear , How we can solve these kind of circuit ?

## marked as duplicate by Qmechanic♦May 4 at 16:32

This question was marked as an exact duplicate of an existing question.

• There are not in series nor in parallel, so you cannot use any of those equivalences. However, Kirchoff's laws still hold. – FGSUZ May 4 at 15:33
• Oh , We haven't study Kirchoff's laws yet , Thank you – Mohammad Alshareef May 4 at 15:42
• This is a somewhat common kind of trick question. By observing the symmetry, you can find that one of the capacitors never has any voltage across it, and therefore can be eliminated, making it possible to combine the remaining capacitors. If you sear here or electronics SE you can find several old questions showing the solution for comparable resistor networks. – The Photon May 4 at 16:33

## 1 Answer

The net capacitance must be 3, You can eliminate the capacitor of 8 farad from the circuit as the design satisfies Wheatstone bridge config(can be proved with Kirchhoff law).

• Please don't give complete answers to homework problems. – Chris May 4 at 16:19
• ... and simply pointing to the Wheatstone bridge is not even an answer. – garyp May 4 at 16:39
• Sorry for that i am still learning thanks for pointing out – Mohit Jani May 4 at 18:35
• @MohitJani , How did you know that can be eliminated ? – Mohammad Alshareef May 6 at 13:13
• search for wheatstone bridge on wikipedia, most probably you will find about resistors but if you apply the voltage equations of capacitor it works. – Mohit Jani May 11 at 16:41