Generating Electricity

Date: Tue Dec 15 1998 - 15:15:32 PST

Dear Sally --

Yes, it's possible to build a generator which will light a very small light.
One homemade generator that was built by a teacher in one of our summer
institutes used a small length of PVC pipe with a steel bolt inside running
its length (with a nut on the threaded end to hold it in place). Lots of thin
wire was wrapped around the pipe, and a small incandescent light bulb was
attached to the ends of the coil. The pipe was then pivoted so that the coil
was spun between two neodymium magnets. It's difficult to give the
construction details without diagrams and still keep the writing to a
reasnable length!

There is another design which is simpler, and does not involve neodymium
magnets. It can be built with cheap Radio Shack ceramic donut magnets, and a
cheap Radio Shack LED. We call it the Stripped Down Generator. It involves
wrapping about 500 turns of #26 magnet wire around the middle of a cardboard
tube from a roll of paper towels, and attaching the LED to the ends of the
coil (the tube is first slit lengthwise and tightened to a smaller diameter so
that plastic film cans can be used to seal the ends). The magnets are then
placed in the tube and the tube is shaken so that the magnets slide rapidly
back and forth in the tube. The LED lights each time the magnets pass through
the coil. Once again, a drawing would be handy! In fact, I can send you a
write-up for this one if you are interested. If you want me to do this, send
me a fax number or a mailing address. My e-mail address is given below.

I hope this helps.

Don Rathjen
Exploratorium Teacher Institute

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