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Non uniformly wound solenoid (no Mag. field?)

  1. Dec 9, 2008 #1
    I made two solenoids using the same amount of wire (1000ft of 24 AWG) around 2 identical bobbins. One of them I painstakingly wound the wire uniformly and tightly. This solenoid is strong enough to pull a steel rod into the middle of the core.

    The other I haphazardly wound as fast and randomly as possible to see what the difference in the magnetic field would be. This solenoid had almost no detectable field. The only way I could detect any magnetic force was by holding a compass at one of the ends of the solenoid and the needle did allign itself wih the field.

    Should the field be dramatically weaker when the solenoid is not uniformly wound? I fear that maybe I accidently reversed the direction I was winding during the winding process.

    Also if the field is dramatically weaker what causes this? I thought perhaps it was because the magnetic fields of each current loop partially cancel out thus weakening the field, but I'm not sure.

    Thanks for the help.
  2. jcsd
  3. Dec 9, 2008 #2


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    The only thing that matters is the number of turns/length and the current.
    If you have managed to wind an equal number of turns each way then you won't have a field - you might also have broken the wire and are only getting a very small current leaking the through the insulation.
  4. Dec 9, 2008 #3
    I see, thanks.
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