Current Discrepancy: Why Positive Charge?

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Discussion Overview

The discussion revolves around the convention of current direction in electrical circuits, specifically the choice to define current as the movement of positive charge despite the actual movement being that of negative electrons. Participants also touch upon the implications of this convention and its historical context, as well as the relationship between magnetic poles and their nomenclature.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants question the advantage of defining current direction as the movement of positive charge when electrons, which carry negative charge, are actually moving.
  • There is a historical perspective mentioned regarding the assumption made before the discovery of electrons, suggesting a 50% chance of being correct in the initial convention.
  • One participant finds it easier to conceptualize current direction in terms of positive charge movement rather than negative charge motion, indicating a personal preference for this convention.
  • Another participant notes that as one progresses in their studies, particularly in solid state physics, they may shift to thinking in terms of electron movement, which aligns with the physical reality of charge flow.
  • There is a mention of the magnetic poles, with a participant humorously suggesting that the north pole of the Earth could be considered the south pole based on compass behavior and historical magnetic pole flips.

Areas of Agreement / Disagreement

Participants express differing views on the utility and implications of the convention of current direction. There is no consensus reached on whether the convention is advantageous or whether it should be reconsidered in light of electron movement.

Contextual Notes

Participants acknowledge the historical context of the convention and the potential for different perspectives based on the area of study, such as circuit analysis versus solid state physics. The discussion reflects varying levels of comfort with the convention and its implications for understanding electrical phenomena.

Opario
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Why would it be an advantage to say that the direction of current in a wire is the "movement" of positive charge, when in fact it is the negative charge on electrons which is moving. And who decided to make that the universal rule, anyway?

And another thing: Isn't the north pole of the Earth really the south pole?
 
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Opario said:
Why would it be an advantage to say that the direction of current in a wire is the "movement" of positive charge, when in fact it is the negative charge on electrons which is moving. And who decided to make that the universal rule, anyway?

Back before electrons were discovered, they had to make an assumption... 50% chance of being right...

Opario said:
And another thing: Isn't the north pole of the Earth really the south pole?

As I recall, the "N" end of a compass needle is termed the "North Seeking" pole.

Since the magnetic poles flip with monotonous regularity, if you hang around long enough the "N" of the compass needle will become the "South Seeking" pole... :biggrin:
 
Opario said:
Why would it be an advantage to say that the direction of current in a wire is the "movement" of positive charge, when in fact it is the negative charge on electrons which is moving.
I just find it easier to think about the direction positive charges would move in a circuit, rather than thinking about negative charge motion and continually reminding myself that the voltmeter or ammeter readings need a sign change.
 
Redbelly98 said:
I just find it easier to think about the direction positive charges would move in a circuit, rather than thinking about negative charge motion and continually reminding myself that the voltmeter or ammeter readings need a sign change.

After you start taking your first solid state physics class, you will probably think more in terms of electron movement. It's physically what's going on, after all, and it turns out not to be very hard to make the mental flip to "positive" current direction.
 
berkeman said:
After you start taking your first solid state physics class, you will probably think more in terms of electron movement. It's physically what's going on, after all, and it turns out not to be very hard to make the mental flip to "positive" current direction.

In that situation, yes you're absolutely right. It all depends on what you are working on. My first (and only) solid state physics class was about 25 years ago. These days I often work with circuits and meter readings.

When I look at what's going on in diodes and transistors I switch back to the electron point of view, it's easier in terms of understanding the physics as you point out.

Regards,

Mark
 

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