Re: Shaker LED flashlight


"linnix" <me@xxxxxxxxxxxxxxxxxx> wrote in message
news:2c916239-5dd1-4d34-8502-2e04e4a413ad@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Jan 9, 3:40 pm, linnix <m...@xxxxxxxxxxxxxxxxxx> wrote:
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.

Correction, digikey has them for 14 cents each in QTY 4000.

And only $4.99 at Radio Shack!
Mike


.

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