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Current Discrepancy

  1. May 12, 2008 #1
    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?
  2. jcsd
  3. May 13, 2008 #2
    Back before electrons were discovered, they had to make an assumption... 50% chance of being right...

    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:
  4. May 13, 2008 #3


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    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.
  5. May 13, 2008 #4


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    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.
  6. May 13, 2008 #5


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    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.


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