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Re: [Phys-l] flashlight : no battery, no bulb



And on the one I bought from them, the so-called capacitors
were in fact batteries. The magnet was vaguely magnetic,
but the wiring was completely a joke. It didn't really
connect to anything.

Zeke Kossover


--- Jack Uretsky <jlu@hep.anl.gov> wrote:

The wiring is very fragile.
Regards,
Jack



On Sun, 1 Jun 2008, John Denker wrote:

The local Walgreens stores are running a clearance on
flashlights.

This is the kind with an LED instead of a bulb, and a
supercapacitor
instead of a battery. You charge it by shaking. The
chassis is
transparent, so you can see the coil and the magnet.

I like them because
-- light weight ==> good for hiking
-- no battery ==> near infinite shelf life
-- LED won't burn out any time soon.
-- small amount of shaking makes rather long-lasting
light
-- physics lesson
-- on sale for $2.00

On the other hand, it looks like they were having
serious production
problems. I had to sort through 12 of them to find 3
that worked.
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--
"Trust me. I have a lot of experience at this."
General Custer's unremembered message to his men,
just before leading them into the Little Big Horn
Valley



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