How Does It Work Crank Powered Lighting

How Does It Work Crank Powered Lighting

By Chris Weiss, eHow Contributor

Introduction
Crank flashlights are very handy devices that are particularly useful in a pinch. No need to worry about charging the flashlight or ensuring it has fresh batteries, the crank flashlight is a great last resort and will always light up your campsite when you need it.

Generator
The crank flashlight contains a small generator much like the ones that are used to provide electricity around the country. The difference is that the flashlight's generator, also called a dynamo, is powered by manual cranking of the arm.

Induction
The principal behind the generator is that of induction. When you move a coil of wire through a magnetic field, a voltage is induced into the wire, which then creates electrical current that flows through the circuit. Inside your crank-powered flashlight is a wire coil that is inside a magnetic field. When you crank the arm of the flashlight, you are actually moving this coil in the magnetic field. As the coil moves, voltage is induced and current then flows through the circuitry and lights the bulb of the flashlight.

Batteries
You've probably noticed that you can crank your flashlight for a few minutes and then get a reliable light source for a while afterward without actively cranking. This is because the crank flashlight has rechargeable battery cells inside that store the energy that you've created from cranking. In this way you don't have to actively crank to use the flashlight, but can crank and then have the flashlight operate on batteries.

How Does It Work Crank Powered Lighting