# Homework Help: RC circuits help

1. Oct 2, 2011

### pyroknife

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

I don't understand why the 3 resistors at the top end up being in series for part b. can someone explain that to me.

2. Relevant equations

3. The attempt at a solution

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2. Oct 2, 2011

### Staff: Mentor

After a long time, when the circuit reaches steady state, the capacitors will be charged to their steady state values and no further current will flow into or out of them. Essentially, as far as the current is concerned, they no longer exist in the circuit.

If you take your eraser and remove the capacitors, what doe the circuit look like?

3. Oct 2, 2011

### pyroknife

Ohh i see thanks a bunch. But even if i erase the capacitors and have just a wire in their place, wouldn't it still look like the 3 are in parallel?

4. Oct 2, 2011

### Staff: Mentor

By erase I mean eliminate completely. Leave no trace! Not even wires!

5. Oct 2, 2011

### pyroknife

Oh i see. part c of the question asks for the charges on the plates of the capacitors a long time after switch S is closed. If I play kirkoff's loop rule to the capacitor with the 10 microfarads, which resistors would I have to include in the equation?

6. Oct 2, 2011

### pyroknife

wait never mind I wasn't thinking. "loop" so I just take one of the triangles at the top and apply the loop rule.