What is the Principle of a Capacitor?

In summary, the textbook states that if plate A is connected to the positive terminal of a battery, then to say plate A is "charged to a maxium", means it has the maximum positive charge possible. However, in reality, the net flow of electrons is from negative potential towards positive potential.
  • #1
Krushnaraj Pandya
Gold Member
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Homework Statement


I was reading through the principle of a capacitor and I am unable to understand one of the statements. My textbook says the following-
Consider an insulated metal plate A. Let it be connected to a voltage source and charged to a maximum. Now an uncharged plate B is brought near it. Due to electrostatic induction negative charge is introduced on the left face and positive charge on the right face.
2. Homework Equations

All electrostatics related formulas.

The Attempt at a Solution


Since plate A is connected to a voltage source, electrons travel from the source to the plate till both are at equal potential. Since plate A has a negative charge it should attract positive charge and thus induce positive charge on the left face and negative on the right of plate B. Where am I wrong?
 
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  • #2
We need to know if your textbook shows plate A connected to the positive terminal of the battery, or whether it shows plate A connected to the negative terminal of the battery.
 
  • #3
Stephen Tashi said:
We need to know if your textbook shows plate A connected to the positive terminal of the battery, or whether it shows plate A connected to the negative terminal of the battery.
it shows nothing. Just this text is written under the heading principle of a capacitor.
 
  • #4
Stephen Tashi said:
We need to know if your textbook shows plate A connected to the positive terminal of the battery, or whether it shows plate A connected to the negative terminal of the battery.
let me attach the photo of the paragraph.Pardon the camera quality, I have no other camera except my webcam.
 

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  • #5
If plate A is connected to the positive terminal of a battery then to say plate A is "charged to a maxium", means it has the maximum positive charge possible - which means plate A has a deficit of electrons, not a surplus of electrons. Perhaps that is what your textbook wants to describe.

In electronics, there is the awkward situation that its mathematics uses the convention that (positive) current flows from positive potential to negative potential. In actuality, the net flow of electrons is from negative potential towards positive potential.
 
  • #6
Stephen Tashi said:
If plate A is connected to the positive terminal of a battery then to say plate A is "charged to a maxium", means it has the maximum positive charge possible - which means plate A has a deficit of electrons, not a surplus of electrons. Perhaps that is what your textbook wants to describe.

In electronics, there is the awkward situation that its mathematics uses the convention that (positive) current flows from positive potential to negative potential. In actuality, the net flow of electrons is from negative potential towards positive potential.
alright, got it. Thank you very much.
 

FAQ: What is the Principle of a Capacitor?

What is a capacitor?

A capacitor is an electronic component that is used to store electrical charge. It consists of two conductive plates separated by an insulating material, known as a dielectric.

How does a capacitor work?

When a voltage is applied to a capacitor, it stores electrical charge on its plates. The amount of charge stored is directly proportional to the applied voltage and the capacitance of the capacitor. This stored charge can then be released when the capacitor is connected to a circuit, making it useful for smoothing out voltage fluctuations or for timing circuits.

What is the principle behind a capacitor?

The principle behind a capacitor is that when two conductive plates are separated by an insulating material, an electric field is created between them. This electric field allows for the storage of electrical charge on the plates, and the amount of charge that can be stored is determined by the properties of the dielectric and the distance between the plates.

What factors affect the capacitance of a capacitor?

The capacitance of a capacitor is affected by the surface area of the plates, the distance between the plates, and the dielectric material used. Generally, larger surface area and smaller distance between plates result in a higher capacitance, while a higher dielectric constant of the material also increases the capacitance.

What are some common applications of capacitors?

Capacitors have a wide range of applications in electronics, including power supply filtering, voltage regulation, and signal coupling. They are also commonly used in audio equipment, radio frequency circuits, and timer circuits. Capacitors are also essential components in electronic devices such as computers, televisions, and smartphones.

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