1. Sep 18, 2013

### fredrogers3

1. The problem statement, all variables and given/known data

A circuit is constructed with five capacitors and a battery as shown. The values for the capacitors are: C1 = C5 = 4.1 μF, C2 = 3 μF, C3 = 6.8 μF, and C4 = 3.4 μF. The battery voltage is V = 12 V.

I need to find the equivalent capacitance between points a and c.

2. Relevant equations

I have the answer but I am a bit confused as to how it is arrived at. See below.

3. The attempt at a solution

I found the equivalent capacitance between a and b as c234=(c4)+(1/c23)

I see next that c234 is in series with c1 and c5. Why does the equation then become Cac=(1/((1/C1)+(1/C234)) and not (1/((1/C1)+(1/C5)+(1/C234))?

2. Sep 18, 2013

### iRaid

You can neglect c5 since it doesn't affect the capacitance at a or b since the current is flowing clockwise.

3. Sep 18, 2013

### Staff: Mentor

Apparently they're only looking for the capacitance to the right of the points a and c. This is not clear in your problem description, so perhaps the problem is stated differently in the original?

4. Sep 18, 2013

### fredrogers3

This was exactly the way the problem was written, so it left me a little confused as well

5. Sep 18, 2013

### Staff: Mentor

Current direction doesn't affect equivalent capacitance! Not unless there's a nonlinear circuit element like an open switch or a diode involved that would prevent "seeing" the capacitance.