Flashlight: Difference between revisions

Some flashlights have an electrical generator built into them. Dynamo-powered flashlights have a winding crank connected to a stepper [[Electrical motor|motor]] that feeds several [[diode bridge]]s with their outputs connected in parallel feeding a [[field effect transistor]] that charges a capacitor that connects to one or more LEDs. Others generate electricity using electromagnetic induction. They use a strong permanent magnet that can freely slide up and down a tube, passing through a coil of wire as it does. Shaking the flashlight will charge a [[capacitor]] or a rechargeable [[Battery (electricity)|battery]] that supplies a [[Current (electricity)|current]] to a [[Lighting|light source]], typically a light-emitting diode or, more rarely, an incandescent light bulb.