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My made solenoid doesnt induce magnetic field. What did I miss?

  1. Apr 25, 2009 #1
    Hey, I have a school project and I need a solenoid to induce a magnetic field.
    http://www.yourpicbox.com/images/orhBIhKZq6426.jpg
    I made a solenoid by winding a wire (I'm not sure what to call this wire. It's thin and brown.) to a pen case. I made 3 layers, 100-200 turns each.
    When I tested it, connecting it to 6V DC, nothing happened. No magnet.

    So I experimented other thing :
    I connect a LED and 1.5V DC with this wire. LED didnt glow.
    Then I change this wire with ordinary insulated copper wire. The LED glow brightly.

    It seems that this wire doesn't conduct any current. What did I miss here?
     
    Last edited by a moderator: Apr 24, 2017
  2. jcsd
  3. Apr 25, 2009 #2
    A solenoid like that can quickly drain power from the battery. Try another battery, or another power supply. Also, did you scrape the insulation on the wire when connecting to the battery?
     
  4. Apr 25, 2009 #3

    uart

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    Yes it sounds like you just haven't made proper connection to the ends of the wire. It often can be quite tricky to make a good electrical connection to enamelled wire. I recommend that you try the following procedure :

    1. Burn off the insulation near the ends with a cigarette lighter.

    2. Scrap away the burnt enamel with steel wool until you see shiny copper visible.

    3. Solder short pieces of regular insulated copper wire (preferably "tinned" though it's not essential) to the ends where you're cleaned off the enamel. You'll find that this regular type wire is much easier to work with and make connection to your battery or other circuitry. Also, if you get the solder to stick well then you know the enamel is properly removed and the connections will be good.
     
  5. Apr 25, 2009 #4
    As an alternative, it's also easy to scrape the insulation with sand paper.
     
  6. Apr 25, 2009 #5
    thanks
    I did not know the wire is insulated.
    It works just fine after I scrap it :)
    many thanks
     
  7. Apr 25, 2009 #6

    uart

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    Science Advisor

    Think about it, if that wire wasn't insulated then all the turns would be touching each other and all you'd end up with is a big short circuit. :)
     
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