So..What would be the most efficient miniature dynamo system? So my question to you, on the small scale, what would be the most efficient dynamo system? Small scale meaning a handheld size device. I know energy can be generated using Faraday's law, when you move a magnet near a coil it generates electricity. But how much, and which configuration would be optimum? Its been a while since I went to engineering school so I would like to learn a few things. Which is more important, should we focus on the Joules (weight energy) and physical force to turn a dynamo wheel, or is simply the moving of the magnet important, and the speed in which it moves? Is it better to turn a dynamo wheel using Joules, or is it better to have a moving magnet, light as a feather, exerting no force on the dynamo, and just magnetically generating electricity in the coils? And, where would I get and purchase one of these devices, these dynamo devices? For example, the system energy I wish to transfer into the dynamo, is 0.02 Joules. The speed at which a magnet could move (in order to generate electricity) is .51 m/s. How much energy could I get from this? I would like a reference, specifically how much energy does it take to generate a electromagnetic field equivalent to the strength of a fridge magnet that lasts for 10 seconds?