# Capacitors in series and Parallel

1. Apr 13, 2016

### KieranRC

There are a few problems here but it would be helpful if The below solutions could be checked and some insight provided for the last one/any other mistakes

The problem & The Solution Attempts

A circuit with a 12V battery then on the row below in series with the battery is a 120nF capacitor and a
3.2(mu)F capacitor then in parallel with those resistors is another resistor of 50nF. On the immediate left of the battery is a 270Ohm resistor.

First I am asked to calculate the equivalent capacitance of the two capacitors in series for which I did:
(1.2x10^-7) + (3.2x10^-6) = 3.32x10^-6 F

Next I was asked to work out the equivalent capacitance of this capacitor network
For which I did:

((1.2x10^-7)x(3.2x10^-6)) / ((1.2x10^-7)+(3.2x10^-6))= 1.16x10^-7

(1.16x10^-7) + (5x10^-8) = 1.66x10-7F

After this I was then asked to calculate the maximum charge that can be stored in this capacitor network for which i did:

(1.66x10-7)(12)=1.992x10^-6C

Then last but not least I was asked to calculate the maximum energy that could be stored in the smallest capacitor and I have no idea where to start.

Thank You

2. Apr 13, 2016

### stevendaryl

Staff Emeritus

3. Apr 13, 2016

### stevendaryl

Staff Emeritus
I think the only additional fact you need is the formula for the energy in a capacitor: $E = \frac{1}{2} C V^2$

4. Apr 13, 2016

### KieranRC

Okay great, thank you.
Does everything else look right to you?

5. Apr 13, 2016

### Staff: Mentor

This is unclear. You are mentioning resistors that you haven't described yet. How does what you describe form a closed path ("circuit")? What does the resistor in parallel with the battery do? (Is it a resistor?).

That is not correct. Series capacitors do not simply sum. Capacitors in parallel sum. Where is your Relevant Equations section of the required formatting template? You should have listed the equations required to combine capacitors in series and in parallel.

Please use the formatting template when posting questions in the homework area.

6. Apr 13, 2016

### KieranRC

7. Apr 13, 2016

### Staff: Mentor

Use the UPLOAD button at the bottom right of the edit panel.

8. Apr 13, 2016

### KieranRC

1. The problem statement, all variables and given/known data
Shown in
2. Relevant equations

3. The attempt at a solution

9. Apr 13, 2016

### KieranRC

Is this okay? I have uploaded a photo of the problem

10. Apr 13, 2016

### Staff: Mentor

Yes, it's fine.