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I want to generate my own electricity via the included method

  1. Aug 5, 2013 #1


    "So if I have a magnetic field that's increasing increasing increasing"

    I'm probably taking this too literal, but the magnetic field coming from the neo magnet isn't increasing or decreasing. The gentleman is only moving the magnetic field (the magnet) in closer proximity to the coil, so the intensity increases relative to the coil's position.


    "current's gonna flow in the loop to fight that change"

    What defines initial direction of current flow? Polarity of the magnet relative to the coil's position? Perhaps position of coil is irrelevant?

    I've been watching the galvanometer. When you move a magnet into a coil, you need to move it back. This is why the needle jumps from + to -. That's AC correct? How do you generate DC? Keep the magnet in a single position & turn it one direction & one direction only?

    Frequency = # of oscillations per second. If I were to build one of these at home, I don't think I could get the needle to jump +6v to -6v every time. I'm sure this happens in generators. How do you smooth it out? Does it even matter? & wouldn't this have an affect on Frequency? Just assume the needled jumped from +6v to -4v. I'm sure it'd take a shorter amount of time for the needle to move from -4v back to 0 vs the time it took to go from 0 to +6v
    Last edited by a moderator: Sep 25, 2014
  2. jcsd
  3. Aug 6, 2013 #2


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    Generators use brushes to create DC, alternators use rectifiers.

    The direction of the magnetic field, the direction of force, and the direction of current are all perpendicular. (see Left Hand Rule).

    The frequency is set by the rate of the direction or velocity changes of the field. The amplitude may vary, but there is effectively a zero crossing everytime you change direction and a change in current everytime you change velocity.
  4. Aug 6, 2013 #3

    Simon Bridge

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    If you move a magnet towards a plane conductor, a circular current is induced, which has a magnetic field, which opposes the motion of the magnet. Thus a north pole moving towards a sheet of metal induces a north pole facing it in the surface. When it tries to move away, it induces a south pole.

    The wire in a coil constrains the current to move along it - around the coils.
    So the direction of current in the wire of a coil depends on the motion of the magnet, the orientation of the magnet, and the direction of the turns.
  5. Aug 6, 2013 #4


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    The title of the thread suggests that the OP has it in mind to power his home with a coil and a magnet. In fact, the youtube video just demonstrates the basic principle of induction. (There are many better presentations than that one, btw). Generating lots of Electrical Energy requires a lot of energy to be input, in the form of fuel, wind, moving water etc - Joule for Joule. It's easy enough to produce detectable voltages with a few mA but no more.

    Most designs of generator involve rotation - either a rotating magnet or a rotating coil. This will, inherently produce an alternating voltage which has to be rectified, using rectifiers or a commutator (switching mechanism).
  6. Aug 7, 2013 #5

    Simon Bridge

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    Yeah - it's one thing to answer the questions and something else to address the overall goal behind the questions.
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