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Q & A: Powering-Up Home-Made Electromagnets

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Most recent answer: 10/22/2007
Q:
how do i intensifi a magnet that is made by wraping wires without short circuiting? could i have a powerful battery with a long cord, wrap it aroud a metal bar, then have the end of the wire go to a light buld of something like that so the wire won’t get hot and without short circuting?
- nick (age 14)
st. louis, MO, USA
A:
Nick -

The important factors for determining how strong a magnet like this will be is how many times you wrap the wire around the metal and to how much current is flowing in the wire. More wraps and/or more current means a stronger magnet.

The amount of heat that is produced will be proportional to the square of the current that flows, so you are right to worry about this. A nice way to get around this problem is to wrap a fairly thin wire many many times. This has the effect of making the current smaller since the wire is long (and thus has higher resistance than a short wire), and having many loops keeps the magnet just as strong, as I said above.

You can power this with a normal battery. To keep it from getting hot, all you have to do is use the right size battery. A fairly small one should work fine, although the exact size that works best depends on the wires you're using and how you have them set up.

-Tamara

(published on 10/22/2007)

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