In message , geoff
smith writes
I have seen an advert for an L.E.D flashlight that is activated by shaking
it,there are no batteries.
How does it work ?


from http://www.generationgear.com/produc...echnology.html

"
It all started back in 1830 when the English physicist Michael Faraday
discovered that passing a magnet near a wire coil could induce an
electric current in the wire. This "Faraday Principle" forms the
foundation for all of today's electric motors, generators, &
transformers.

Generation Gear has taken this principle to the next level. We have
combined it with two advanced semiconductor devices to create a
flashlight that never needs batteries!

Shaking the ShakeLight will cause a magnet to slide back and forth
inside the flashlight handle. As it does so, it passes through a copper
coil, thereby inducing a current in the coil's wire. This current is
then stored inside an electronic component called a capacitor which in
turn provides power to the LED (Light Emitting Diode).
"

--
dave @ stejonda

Beyond the farmyard the wind in the trees.