Tesla is most famous for conceiving the rotating magnetic field principle (1882) and then using it to invent the induction motor together with the accompanying alternating current long-distance electrical transmission system (1888). He developed numerous other electrical and mechanical devices including the fundamental principles and machinery of wireless technology, the high frequency alternator, as well as other devices such as the devices for high voltage discharges, and the bifilar coil. He developed various devices that use rotating magnetic fields, the fundamental devices and systems of wireless communication , radio frequency oscillators, devices for voltage magnification by standing waves, robotics, devices for x-rays.