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DiscoverCircuits.com -- Hobby Corner
Last Updated on:
Tuesday, June 01, 2021 03:06 PM
Hobby Circuits List
The contents &
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LINK to Dave's circuit, but DO NOT COPY any files to your WEB
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Shake to Charge Flashlight --
of 4
designed
by David A. Johnson, P.E. |
| Have you ever wondered
how some of those “Forever” flashlights work? These devices appeared several
years ago and are often sold on some TV home shopping networks. A company in
Colorado: (Applied Innovative Technologies
www.appliedinnotech.com) made the original device but knock-offs from China are now
popping up everywhere. That fact that some of those devices don’t even work
will be a topic for later discussions. |
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Shake & Charge Flashlight |
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| I
bought one of the cheaper counterfeit devices and took it apart. There were no
manufacture or country of origin markings anywhere on the device. I traced out the
circuit. It is not much more than a coil of wire, a magnet, a bridge rectifier,
super capacitor and white LED. A small magnet attached to an on/off switch is used
to turn on the light by activating an internal reed relay. This method maintains a
tight weatherproof seal and is about the only thing I found cleaver about the device.
Shaking the thing forces a large magnet slug to slide back and forth inside the body of
the device. Two rubber stoppers cushion the magnet at each end. In some other more
expensive shake to charge flashlights, they use two more magnets as contact-less
bumpers. |
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