How to Build Small Electromagnetic Generators
You can make a simple hand-cranked, alternating-current generator with magnets, wire, a nail and some cardboard. The basis of an A/C generator is to cut the magnetic field lines of magnets with the coils of an electric circuit. This will produce an electromotive force on the electrons in the circuit, as demonstrated independently by British scientist Michael Faraday and American Joseph Henry in 1831.
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Things You'll Need
- Insulated copper wire
- Nail
- Cardboard
- Light bulb
- Small square magnets
- Electrical tape
Instructions
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1
Fold a piece of cardboard over on itself, making an enclosure with two open ends. In other words, make four folds, to create four faces at right angles with each other, with one face consisting of two overlapping ends. The shortest width of the enclosure should be a little wider than your magnets, since you'll fit them inside to be hand cranked.
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2
Push a nail through both sides of the center of the enclosure's two broad sides.
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3
Stack an equal number of magnets on opposite sides of the nail within the cardboard enclosure. Wrap electrical tape around the two stacks of magnets and the nail for stability.
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4
Wrap the thinly coated wire around the cardboard enclosure dozens of times---or hundreds, if the wire is thin. Wrap in only one direction, so that the induction will push the electrons in the same direction. The windings will be parallel and should be close to the nail, for full effect.
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5
Cut the wire and strip the insulation off the two ends of the wire (with scissors will do), and attach the bare ends to the two terminals of a light bulb. Hold them in position with electrical tape because you'll need your hands free to crank the magnet.
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6
Spin the nail and watch the bulb light up. You've just created an alternating current of electricity, cutting the magnets' lines of force by spinning through the coils of wire.
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