Capacitor with connections on inner surfaces

In summary, when a capacitor C is connected to a battery and switch, current will flow and the capacitor will charge until the potential difference equals the voltage of the battery. The e-fields inside the capacitor will not enter the wires, and the wires being between the plates will not affect the charging process. For an infinite parallel-plate capacitor, the e-field outside the capacitor is zero, while for a finite plate capacitor, the e-field is not zero but will approach zero as we approach infinity. The e-field inside the capacitor will always be uniform, and the wires will act as part of the capacitor plates. As a result, the battery will create the necessary conditions for the e-field inside the wires to exceed that on the plates, allowing the
  • #1
sridhar10chitta
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0
A capacitor C is made from large disks with a very large R and the gap between the plates s is very small (s<<R). The connections to the plates are made
"inside" the capacitor (on the inner surfaces) at the center of the plates. The capacitor is hooked up to a battery and switch. The circuit is closed. What will happen ?
 

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  • #2
Current will flow and the capacitor will charge until the potential difference equals V of the battery. The wires being between the plates changes nothing.
 
  • #3
fields inside the capacitor

will not the e-fields that are stronger inside the capacitor prevent the capacitor from charging ? could you describe a charging mechanism scenario ?
 
  • #4
The E field inside the capacitor does not enter the wires.
 
  • #5
Why does not the E field enter the wires ?
 
  • #6
Consider an infinite parallel-plate cap.

sridhar10chitta said:
Why does not the E field enter the wires ?

For a infinite plate parallel plate capacitor, the e-field outside the capacitor is zero. If you consider placing two such plates in parallel with each other, each having different charges. An electric field will form between the plates (a capacitor). But what about the e-field outside? In order for there to be zero e-field, some cancellation must occur. This is exactly what happens:
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Capacitors/ParallCap.html [Broken]

However with a finite plate capacitor, this is not the case i.e. the e-field outside the cap is not zero. However, for regions close to the capacitor, the plates will look as if they extend to infinity. This is similar to the above situation where we have zero e-field outside. Just remember that the potential falls off to zero as we approach infinity on an infinite plate capacitor. Zero potential = no e-field outside the cap.
 
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  • #7
The e-field "inside" the capacitor will always be (Q/A) / epsilono and nearly uniform all over inside in the gap.
 
  • #8
Since there are no significant quantum effects in this arrangement, the capacitor will act as a "shorted" capacitor, rendering it's usefullness void.
 
  • #9
The anwer provided by Clem is apparently right. The battery will create the necessary conditions for the driving e-field inside the wires to exceed that developing on the plates and the "Current will flow and the capacitor will charge until the potential difference equals V of the battery. The wires being between the plates changes nothing."
 
  • #10
>>> The e-field "inside" the capacitor will always be (Q/A) / epsilono and nearly uniform all over inside in the gap.

This is only true for an ideal parallel plate capacitor and I don't think it applies precisely to your situation. Once you place the leads between the plates the real capacitor takes on a new geometry and the capacitance and distribution of the electric field change accordingly. In other words the outer surface of the wires are part of the capacitor plates. As a practical matter if the leads are much smaller than the plates then the effect will be minimum and you can use the ideal parallel plate equation as an approximation.
 
  • #11
David you are right. But let us not forget the orignal question which was "what will happen" and the answer is that the "battery will create the necessary conditions for the driving e-field inside the wires to exceed that developing on the plates and the Current will flow and the capacitor will charge until the potential difference equals V of the battery. The wires being between the plates changes nothing."
 

What is a capacitor?

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

How does a capacitor work?

A capacitor works by accumulating charge on its plates when connected to a power source. When the power source is disconnected, the capacitor releases the stored charge. This allows it to temporarily store and regulate electrical energy.

What are the inner surface connections on a capacitor?

The inner surface connections on a capacitor refer to the conductive plates inside the capacitor. These plates are connected to the leads of the capacitor and are responsible for storing and releasing the electrical charge.

What is the purpose of the dielectric material in a capacitor?

The dielectric material in a capacitor serves as an insulator between the two conductive plates. It prevents the flow of direct current between the plates, allowing the capacitor to store and release charge without discharging quickly.

What are some common uses of capacitors?

Capacitors have a wide range of applications in electronic devices. They are commonly used in power supplies, audio amplifiers, and electronic filters. They are also used in timing circuits, energy storage systems, and in many other electronic components.

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