This is an AC electric generator which lights up a tiny
incandescent light bulb. The generator is made from a hollow-ended
cardboard box with a nail through the center. The box has many turns of
fine copper wire wound around it, with four large magnets clamped around
the nail. When the nail and magnets are spun fast by hand, the little
light bulb lights up dimly.
I wrote this article because I found lots of projects for making a simple
electric motor, but nobody gave the secret for making a generator. Well,
here it is: use strong magnets, lots of fine wire, and a special light
bulb which only needs 1/2 volt. Also, don't bother making a "commutator,"
just hook the wires directly to the bulb. It's much simpler that way,
but the generator will produce AC (alternating current).
Before you start, here are some notes: you must use a special light bulb.
Normal flashlight bulbs will not work. Also, you must use the large,
strong magnets shown in the parts list. Smaller magnets won't work. The
wire must be #30 gauge or smaller. Also, you can improve the generator
if you buy lots of extra wire and wind it on the cardboard, since the
bulb will light up even when the generator spins slowly.