Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

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

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.