Capacitor in Series and Parallel

In summary: Just plug in the equivalent capacitance and the voltage and current in each step and solve for the charge.
  • #1
Heat
273
0

Homework Statement


In the figure View Figure , each capacitor has 4.00 micro F and V = 34.0 V.

YF-24-15.jpg

Calculate the charge on each capacitor.

Homework Equations



Q= CV

The Attempt at a Solution



I know that to get the charge of a capacitor we need to use Q = CV, also that capacitor in parallel add, and capacitor in series add reciprocals.

This is what I thought it would be with charge on each of 0.

6htk6s.jpg
 
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  • #2
I don't know what you mean by having 0 charge, but try using a table:

[tex]
\begin{array}{|c|c|c|c|}
\hline
& C & V & Q \\
\hline
1 &\qquad &\qquad &\qquad \\
2&&&\\
3&&&\\
4&&&\\
eq&&&\\
1,2&&&\\
1,2,3&&&\\
\hline
\end{array}
[/tex]
 
Last edited:
  • #3
It seems that the best way to work out this problem would be to find the equivalent capacitance and then the total charge. Once you have this, work your way back to the original circuit step by step and in the process find the charge. This is analogous to a series-parallel resistor network.

The thing is that charge on the plates of the capacitor are equal but opposite. That gives a total net charge of zero. Unfortunately the answer to your problem is not zero. When they ask to find charge, they don't mean net charge. Instead they want the charge on either plate, -Q or +Q. Quantity is the same, but their signs are opposite.
 
  • #4
Start out with this:
YF-24-15.jpg


So, I got the C equiv for the parallel as shown below:
2eumjoy.jpg


and I got the series as shown below:
2jezj9x.jpg


but how do I simplify this even more, because I notice there is a d point there, and don't know what to do with it.

(I edited the last two. o:) )
 
  • #5
Heat said:
but how do I simplify this even more, because I notice there is a d point there, and don't know what to do with it.

Just ignore it. All it is is a reference to a specific spot on the wire. It doesn't represent any physical object.

EDIT:
oh, and what program did you use to draw the diagrams?
 
  • #6
The first image was given by the problem..the rest I just edited in photoshop. so I treat the circuit as a series now? If so, what do I do with the equivalent capacitance?
 
  • #7
With the equivalent capacitance you can find the total charge. Then work your way back to the original circuit one step at a time, while finding the charge and voltage in each step. Its like working backwards from the equivalent capacitance to the original circuit. Remember the same rules that apply for series and parallel networks (in terms of voltage and current or charge in this case) will work here.
 

Related to Capacitor in Series and Parallel

1. What is a capacitor?

A capacitor is a passive electronic component that stores electrical energy in the form of an electric field. It is made up of two conductive plates separated by an insulating material called a dielectric.

2. What is the difference between capacitors in series and parallel?

Capacitors in series have the same charge on each plate and share the same voltage, while capacitors in parallel have the same voltage across each capacitor but different charge on each plate.

3. How do you calculate the equivalent capacitance of capacitors in series?

The equivalent capacitance of capacitors in series is equal to the reciprocal of the sum of the reciprocals of each individual capacitance. In other words, 1/Ceq = 1/C1 + 1/C2 + 1/C3 + ...

4. How do you calculate the equivalent capacitance of capacitors in parallel?

The equivalent capacitance of capacitors in parallel is equal to the sum of the individual capacitances. In other words, Ceq = C1 + C2 + C3 + ...

5. What is the purpose of using capacitors in series and parallel?

Using capacitors in series and parallel allows for the manipulation of the overall capacitance in a circuit. This can be useful for filtering, tuning, and storing energy in electronic circuits.

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