I know this is a bit of a newbie question but I want to learn something about generators. I want to build a simple hand cranked generator. Just a hobby. Making coils, and using magnets is the easy part but I don't understand the specifics around this. Can anyone tell me how to determine how big the coil must be to generate a certain amount of volts and amps. Is there a formula or methodology for this or is it not possible to determine? For example. Do I need x length of wire at y thickness and N50 magnets to generate ABC Volts and D Amps? Is there a book or something I can read all about this topic. Something not too extensive but clear and easier than a medical journal to understand. Thanks in advance.