Batteryless [Shake] Flashlight Operation Explained
DR. KNOWLEDGE writing over at The Boston Globe has posted an explanation on just how the Shake Flashlight produces illumination. ‘The main idea behind batteryless flashlights is to use the physical motion of the flashlight itself to provide the energy to light up the bulb -- that is, you have to shake it. What happens is always a variant on the following basic idea: If you have a coil of wire and drop a magnet through it, this will make some electricity flow through the coil and whatever it's attached to. This electricity can be stored to power a light bulb.’