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Voice coil polarization

  1. Feb 23, 2015 #1
    I know that a linear voice coil is polarized from top to bottom, but how is a flat coil polarized? Would a flat coil be polarized from the inside to the outside? Where the inside(blue) is one pole and the outside(red) is the other? If you were to do multiple windings(stacked layers) would it stay polarized that way, or would it start to become polarized from top to bottom since it would start to resemble a linear coil?
    I can't find any info on flat coil windings.
    Thanks.
    flat-coil.jpg
     
  2. jcsd
  3. Feb 23, 2015 #2
    Think of each tiny segment of coil as having a solenoid field which follows the right-hand rule, and after a bit it becomes apparent that all the solenoids are adding / cancelling to form a net circulating field similar to that of a short, axially magnetized magnet. Bunting magnetics has a field calculator that can help envision such a field.

    - Mike
     
  4. Feb 23, 2015 #3
    Eeek! I made a mistake. Well, a lot of them, but the one in question regards the magnetic field calculator. It's at K&J magnetics.

    Sorry for any time I may have wasted...
     
  5. Mar 3, 2015 #4
    So it's still just axially magnetized? I made a crude flat voice coil(round magnet wire doesn't like to stay put) and couldn't get it to attract/repel a neodymium magnet at the center of it. It would only attract/repel towards the ends of it, like a linear voice coil, so I incorrectly figured that's where the poles were. If the pole is at the face, why wouldn't it have the strongest force at the center of it?
    Thanks.
     
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