Ever since I started reading about electrostatics and current electricity I have gotten ever so confused by various things. After watching video lectures by several different people and reading several different books on the topics I think I have somewhat got an understanding. My question is whether my understanding of how a battery works is correct or am I still misinterpreting something. My understanding is as follows:
A battery provides a force onto an electron at the positive terminal and does work on it to move it against the electric field to the negative terminal. This work done on the electron is stored as potential energy of the battery.
Now the electron is not held in place by any force so the potential energy is converted to kinetic energy (since it is repelled by the negative terminal of the battery).
This kinetic energy is depleted as the electron moves through the circuit due to collisions with other particles and electrons. Areas of higher resistance cause more collisions and hence more kinetic energy is transformed into heat and light energy. Now unless the resistance is infinite the elections will always have some amount of kinetic energy that will allow them to reach back to the positive terminal of the battery. Now the process repeats.
I am pretty sure I have still missed something about how exactly the electron "passes" through the battery as I am not sure whether it actually physically passes through the battery or for some reason it reaches the positive terminal and a different electron is emitted out on the other side.
I would be really thankful if someone could take a few minutes to read the essay I have written above and let me know if I am right or wrong.
Best Answer
This is not too bad, but you are neglecting the electrolyte. In a battery there are two electrodes. At one, an electron is consumed in the electrode and at the other an electron is produced in the electrode. Conversely, at one an ion is produced in the electrolyte and at the other an ion is consumed in the electrolyte. In the electrolyte the ions move to produce current from one electrode to the other. (Note that this usually involves positive charge carriers moving in the direction of the current as well as negative charge carriers moving in the opposite direction)
The KE of the electron is not at any time relevant in an ordinary circuit. Electrons are very light and their drift velocity is very slow. So $1/2 \ mv^2$ is insignificant for them.
The electrons do not carry energy in a standard circuit. The energy is carried by the fields. This is governed by Poynting’s theorem. The role of the electrons is not to carry energy, but to create the fields that in turn actually carry the energy.