# Principle of a capacitor

• Krushnaraj Pandya
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.

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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?

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.

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.

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.

#### Attachments

• WIN_20180805_14_09_35_Pro.jpg
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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.

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.