Hey, I hope I don't bother any of the serious electrical engineers, but I was wondering if anybody could help me with a project I'm working on. I want to build a generator that I can attach to my stationary bike that will charge my phone. It has a very simple design, two permanent magnets that create a magnetic field around a coil which gets rotated by the bicycle. The part that I'm stuck is what to do now with the two ends of copper wire from the coil. The potential difference produced will be sinusoidal, and I know that wall sockets use 60 hertz AC current, which is what I normally charge my phone with, so is it even necessary to use a commuter and another coil to make DC current? Or can I let the current alternate and connect the circuit up to a USB converter?