English: An early example of an incandescent light powered wirelessly by electromagnetic induction, in 1910. The large cylinder, bottom consists of an electromagnet, a coil of wire with alternating current through it. It creates an alternating magnetic field. The lamp is attached to another coil of wire, which is held above the magnet's pole. The time varying magnetic field induces an alternating current in the second coil, which lights the lamp. The lamp appears to be an original Edison lamp with a carbon filament.