Question about the concept of electricity in solar cells.

Click For Summary

Discussion Overview

The discussion revolves around the concept of electricity in solar cells and other electrical systems, focusing on the behavior of electrons in circuits, their replenishment, and the implications for calculations related to electrical output. The scope includes conceptual understanding and technical clarification.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about how electrons are replenished in solar cells after being freed by incoming photons, questioning whether they draw electrons from the surrounding environment.
  • Another participant asserts that there are always two wires in a circuit, implying that electrons leave one wire and return through another.
  • A different participant asks about the source of the "endless supply" of electrons in a circuit.
  • One participant explains that the electrons are already present in the material and are simply being moved around the circuit.
  • Another participant uses an analogy of a pump and hose to illustrate how electrons circulate in a circuit, similar to water in a closed loop.
  • A later reply reflects on misconceptions stemming from introductory physics education, suggesting that it fails to adequately explain the practical workings of current in motors.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the behavior of electrons in circuits, with some clarifying misconceptions while others raise further questions. The discussion does not reach a consensus on the initial participant's concerns about electron replenishment.

Contextual Notes

Some assumptions about the nature of electric current and the behavior of electrons in circuits may not be fully addressed, leading to potential misunderstandings. The discussion also reflects a lack of detailed exploration into the physical principles governing electron movement and circuit functionality.

Who May Find This Useful

This discussion may be useful for individuals interested in the foundational concepts of electricity, particularly in relation to solar cells and circuit behavior, as well as those seeking to clarify common misconceptions in introductory physics.

LogicX
Messages
175
Reaction score
1
Ok so I understand how a voltage source works, with electrons flowing from a high potential to a low potential. But I'm a little confused about solar cells. So the way they work is that an incoming photon strikes an electron and gives it enough energy to break free and create a current. But how do the electrons get replenished? Why does material not run out of electrons? Does it yank off electrons from surrounding air? If so, would running a solar cell in a complete vacuum eventually stop producing electricity?

Or what about, say, a power generator from a waterfall. As those turbines turn and release electrons, how do the electrons get back? Is there just a positive electric field surrounding any material being used like that?

If I am right, is this something that has to be accounted for? Like, you are doing a calculation to determine the output of a solar cell, but you have to take into account that at any given time there are going to be a less than ideal amount of electrons in the material to create a current?

Just something I have been thinking about for the past couple days, thanks!
 
Physics news on Phys.org
There's always two wires; electrons go out one wire and the same number come in the other.
 
Where is this endless supply of electrons coming from?
 
They are the ones that are already there and simply being pushed around in a circle around the circuit.
 
Imagine a pump with a hose running from the output and looping around to the input.

As it pumps, the same water goes round and round.
 
Ah, silly me, for some reason I was thinking of the electrons as actually having to go somewhere else to do work.

You know, I think that is one of the shortcomings of intro physics. They teach you all about equations and how to calculate different values about circuits and such, but they don't ever teach useful things like "this is how a current makes a motor turn", and it leads to misconceptions like I just had.
 

Similar threads

Undergrad Question about electromagnetic spectrum and solar cells
  • · Replies 4 ·
Replies
4
Views
1K
Graduate Current limit through solar cell (forward bias)
  • · Replies 4 ·
Replies
4
Views
2K
Graduate Electromotive force (or E cell?) during charging and discharging
  • · Replies 19 ·
Replies
19
Views
3K
High School PV cell charge separation by an external electric field
  • · Replies 13 ·
Replies
13
Views
3K
How do copper oxide solar cells work?
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad How a Battery creates a Potential difference in an electrical current
  • · Replies 14 ·
Replies
14
Views
6K
Undergrad Question about potential and current in potentiometer circuit
  • · Replies 11 ·
Replies
11
Views
3K
Undergrad Trying to understand the inner workings of a solar cell
  • · Replies 2 ·
Replies
2
Views
2K
Graduate What is going on when a solar cell goes into reverse bias?
  • · Replies 34 ·
2
Replies
34
Views
8K
Undergrad Can infrared photons also eject electrons in 'photoelectric effect'?
  • · Replies 5 ·
Replies
5
Views
3K