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Electromagnet Vibration?

  1. Mar 6, 2009 #1
    Hey, so I just ripped the two permanent magnets out of an old seagate hard drive, and have a breadboard for my electronics class to practice with logic chips, and figured id wrap some wire around one of the magnets and see what happens.

    I got around 10 turns of the wire about the magnet, and noticed when i turned the power on (5V), there was a vibration that could be felt in the magnet/wire. when power was turned off this went away.

    can anyone give me a reason as to what phenomenon this was? My e+m was always shaky, so any help is appreciated
  2. jcsd
  3. Mar 6, 2009 #2
    after some playing around, im deducing this vibration is from the magnetic field in the coil due to current, repelling the magnet, but due to the polar structure of the magnet and the weak field, this leads to a small vibration
  4. Mar 6, 2009 #3


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    Sound like you're using either 5Vac, or there is significant AC present in an otherwise 5 Vdc source. You're pretty much right, this creates an AC component in the coil's magnetic field which creates the vibration.

    I don't know how much current you're drawing, but you might try 3 D-cell batteries as a power source. Those should not cause vibrations.
  5. Mar 6, 2009 #4


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    My guess is the power supply is going into current limit and the pulsing is a sort of sampling that I've seen some supplies use to determine whether or not to try to regulate a constant voltage. Yours may not be the type of supply that I have seen do this, but I thought I'd throw it out.
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