The sound waves produced a mild electrical current of about 50 millivolts. The average cell phone requires a few volts to operate, several times the power this technology can currently produce.
Wrong, so very wrong. Millivolts is not a unit of current, and volts is no unit of power. Nor is power current. I've seen journalists not understanding electrical units before, but never have I seen something quite so wrong as this.
If A = B and B = C, then A = C, except where void or prohibited by law. -- Roy Santoro