Question about Electric Current

Discussion in 'General Science' started by beeson76, Nov 14, 2011.

  1. beeson76

    Thread Starter Member

    Apr 19, 2010
    185
    1
    Im reading the several books and websites and watching the Videos on the website. Im at the point of Inductors. Here is my question.

    When an electrical current flows through a conductor a circular electromagnetic field is generated around the the conductor. Why is this? How is the electric field produced. I know is prolly has to do with a North and South and lines of magnetic flux. But Im just not grasping it.

    Any help is greatly appreciated.
     
  2. BillO

    Well-Known Member

    Nov 24, 2008
    985
    136
    I think you are asking "how is the magnetic field produced?", right?

    The horrible answer is, it just is. This is a physical property of this universe. The fact that a magnetic field is produced, the 'direction' of that filed and its geometry are properties of the flow of electrical charge.

    It may be interesting to note that the magnitude of the magnetic filed is proportional to the Lorentz (Fitzgerald) contraction due to the velocity of the electron flow.

    Asking why though, is like asking why the universe exists, or why blue looks like blue, or why I like Rum 'n' Raisin ice cream ... I just do.
     
  3. beeson76

    Thread Starter Member

    Apr 19, 2010
    185
    1
    Thanks BillO:)

    I know it was bout an impossible question to answer. I was reading about inductors and it just felt like I was missing an important part to understanding them. Like where does the magnetic force come from? What Electrons are involved in the magnetic force being produced...electrons inside the conductor, or electrons outside the conductor?
     
  4. samuelsun

    New Member

    Nov 3, 2010
    10
    0
    yeah i am agree with the BillO..:)
     
  5. Feign

    Active Member

    Mar 30, 2009
    50
    2
    "Because." Is my least favorite answer in the world.

    Have a look at this
    http://en.wikipedia.org/wiki/File:VFPt_dipole_electric.svg
    It's circular (actually doughnut/torid) because the interaction, no interaction and they just dangle.

    http://en.wikipedia.org/wiki/Basics_of_quantum_mechanics#Application_to_the_hydrogen_atom
    Describes the atomic properties that define magnetic potential, of an atom

    Take a line of people all milling about waiting for the concert hall to open, doors open everyone faces front and starts to walk.
    You can picture the electrons sort of doing the same thing. And since they move at near the speed of light they are effectively locked in that state.
    The magnification of the field is related to how many electrons are moving. Like the field collapse in an inducer, the collapse/expansion of the field takes time.
     
  6. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469
    I am also.


    Certainly it is electrons in the conductor, not outside.

    BillO actually alluded to the best answer I know when he said. "It may be interesting to note that the magnitude of the magnetic filed is proportional to the Lorentz (Fitzgerald) contraction due to the velocity of the electron flow."

    This is a very intuitive way to look at it because, although it does not really explain (which is BillO's point) it does allow us to see the origin of magnetic force as directly relatable to electric field force due to charges. The moving electrons have a different charge density than the stationary protons, due to the Fitzgerald contraction. This could be interpreted as a net charge which then can attract similar net charges due to other currents. Hence, this is why two conducting wires might repel or attract one another. It all gets back to covariance of electric and magnetic fields, in different reference frames.

    In post # 17 of the following thread, I reference an interesting article that might provide details you are interested in.

    http://forum.allaboutcircuits.com/showthread.php?t=40604&highlight=lorentz&page=2
     
    Last edited: Nov 21, 2011
  7. justtrying

    Active Member

    Mar 9, 2011
    329
    351
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