Capacitors in a circuit / Calculate total capacitance

In summary, the total capacitance of the system between terminals A and B is 1.625 μF, calculated by connecting the capacitors in series and parallel according to the given equations. The answer obtained by this method does not match the one provided in the book.
  • #1
Rokas_P
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Homework Statement



Capacitors are connected as shown in this diagram:

http://o3xn.files.wordpress.com/2012/04/c4.png

C1 = 2 μF, C2 = 1 μF. What is the total capacitance of the system in between the terminals A and B?

Homework Equations



For capacitors C1 and C2 connected in series, [itex]\dfrac{1}{C_\Sigma}=\dfrac{1}{C_1}+\dfrac{1}{C_2}[/itex]

For capacitors C1 and C2 connected in parallel, [itex]C_\Sigma=C_1+C_2[/itex]

The Attempt at a Solution



The problem here is that my answer doesn't match that in the book. So I just wanted to check if you guys get the same answer as me.

The three rightmost capacitors C1 have a total capacitance of 2/3 μF.
They are connected in parallel to a C2-capacitor, their overall capacitance is 1+2/3=5/3 (μF).
Then we have a C1 in series with what we calculated above in series with yet another C1, which yields 1/(1+3/5)=5/8 (μF).
Last, we have a C2 in parallel with what we calculated above, which yields 1+5/8=13/8=1.625 (μF).

The book gives 1.58 μF.
 
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  • #2
Looks like your answer is correct and the book's is not.
 

FAQ: Capacitors in a circuit / Calculate total capacitance

What is a capacitor and how does it work in a circuit?

A capacitor is an electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by an insulating material, known as the dielectric. When a voltage is applied across the plates, the capacitor stores energy in the form of an electric charge. This stored energy can be released back into the circuit when needed.

How do you calculate the total capacitance in a circuit?

The total capacitance in a circuit is calculated by adding the individual capacitance values of all the capacitors in the circuit. Capacitors connected in series have a total capacitance equal to the reciprocal of the sum of the reciprocals of their individual capacitance values. Capacitors connected in parallel have a total capacitance equal to the sum of their individual capacitance values.

What factors affect the capacitance of a capacitor?

The capacitance of a capacitor is affected by the surface area of its plates, the distance between the plates, and the type of dielectric material used. A larger surface area and smaller distance between the plates result in a higher capacitance. Different types of dielectric materials have different permittivity values, which also affect the capacitance.

How does a capacitor affect the behavior of a circuit?

A capacitor can affect the behavior of a circuit in a few ways. It can act as a temporary energy storage device, releasing stored energy when needed. It can also block direct current (DC) while allowing alternating current (AC) to pass through. In some circuits, capacitors are used to filter out high-frequency noise or to smooth out fluctuations in voltage.

Can capacitors be used in both AC and DC circuits?

Yes, capacitors can be used in both AC and DC circuits. In AC circuits, capacitors are often used in conjunction with resistors to create high-pass or low-pass filters. In DC circuits, capacitors can be used to smooth out voltage fluctuations or to store energy for later use. However, the type and configuration of the circuit will determine the specific application of a capacitor.

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