Re: Shaker LED flashlight

On Jan 9, 1:08 pm, mrdarr...@xxxxxxxxx wrote:
On Jan 9, 10:16 am, "amdx" <a...@xxxxxxxxxxx> wrote:

Just for fun and as a reinforcement of the electricity
books my son has been reading. I bought a shaker flashlight. (magnetic flux
cutting across wire moving electrons , the electrons then stored on plates
of a capacitor) The flashlight has a magnet that slides back and forth
through a coil. The flashlight cost $1.00.
After I opened the package I noted a small screw rattling
inside the light, so I took it apart and I found two cr2032
lithium batteries in series powering the LED. The coil is connected to a
fullwave bridge and the unit has a .22f
capacitor. There is a 10 ohm resistor in series with the LED.
If I remove the batteries and short across the holder the
LED will not light, no matter how much I shake it.
I just found the batteries in there to be a disappointment. :-)
Mike

Well, the good news is, you now know of a cheap source of CR2032
batteries (which can be expensive elsewhere)...

Michael

Actually, there are cheaper sources. I got some of them for a penny
each, after throwing away the ASIC and 100 SMD LEDs. I need a few
thousands of them, but it wouldn't justify the gas cost. CR2032s are
approximately 25 cents each in volume.

.

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