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I have a circuit with capacitors on it:

circuit figure 1

I am trying to figure out the charge on each capacitor.

The following is given:

given

i know that parallel capacitors follow the equation

paraller

and that capacitors in series behave according to this equation: series

I dont know how to use that knowledge to find out the charge of the capacitors. I also dont know how to apply this to find the voltage across all the capacitors and the total voltage.

This is from a homework question but i want to find out the general concepts of calculating voltages and charges on any circuits.

Any help will be greatly appreciated.

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closed as off-topic by AccidentalFourierTransform, stafusa, Kyle Kanos, Jon Custer, Qmechanic Jan 30 '18 at 18:24

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – AccidentalFourierTransform, stafusa, Kyle Kanos, Jon Custer, Qmechanic
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  • $\begingroup$ Just apply Kirchoff's Loop Law and conservation of charge. $\endgroup$ – evil999man May 14 '14 at 8:43
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If two capacitors are in series the charge on them must be the same. This is because there is no source or sink for charge in between the two capacitors:

Capacitors

That means $Q_1 = Q_2$. You know $Q_2$ so you now know $Q_1$ and you can calculate the voltages $V_1$ and $V_2$ and the total voltage across both, $V_{12}$.

Because $C_3$ is parallel with $C_1 + C_2$ you know $V_3 = V_1 + V_2$ and from this you can calculate $Q_3$. Finally, if you calculate the combined capacitance of $C_1$, $C_2$ and $C_3$ and you know the voltage across this combined capacitor $V_{123}$ you can calculate a combined charge $Q_{123}$, and because $C_4$ in series $Q_4 = Q_{123}$.

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