As the story goes, the great Nikola Tesla, who worked for Thomas Edison for a time, ushered in modern electricity by inventing a system of alternating current that was completely different from the vision of Thomas Edison, and completely new to the world.
But the truth is that the electric generator, the foundation of the revolution of abundant electrical power, had already evolved in two forms, the direct current and the alternating current form.
The electric generator was pioneered by Michael Faraday around 1832. It operates by overpowering mysterious magnetic forces. The power input into the system to overpower the magnets gets translated into a flow of electrons, that can be captured by a battery, or sent down wires to run a motor or heat something.
Faraday used a rotating disk and a fixed horseshoe magnet, he captured the electrons with a springy piece of metal along the edge of the disk, which rotated on an axle where the electrons returned.
The Faraday disk generator produced an alternating current as the poles of the magnet alternated from north to south relative to the rotating disk.
Years later, the generator was improved to provide direct current by using a commutator, a gimmick that switched the polarity of the outputs at 180 degree points of rotation.
But over time we learned that the losses from transmitting alternating current over wires were far lower, and the direct current generator is now very rare. Even a cars alternator produces alternating current, but they are packaged with a rectifier and a regulator.
You might be aware that there is probably a transformer on an electrical pole not far from your house. But do not forget the every iPhone charger and laptop battery charger is also a transformer. The modern sophisticated electrical grid would not be possible without transformers.
Faraday also deserves a lot of credit for the transformer, as he used mathematics to describe how magnetic forces and alternating currents effected the flow of electrons.
Faraday was not alone discovering the effects of magnetic forces on themselves and other things, but he was probably the best theoretical mathematician in his field and at the time. In 1831, another scientist, Joseph Henry, was documenting similar findings. Faraday was in England and Henry was in America.
So what did Nikola Tesla invent?
Nothing really, most of his hands on experiments were utter failures. But he was probably aware of the works of Galileo Ferraris and Mikhail Dolivo-Dobrovolsky. He might have noticed that John Hopkinson received a British patent for three phase electrical transmission and distribution in 1882.
Tesla was crazy, but brilliant, and he could read the math and understand the phases and sines and cosines. More so, Tesla envisioned the problems and solutions. Westinghouse was the hands on guy that turned Niagara Falls into a revolution, but certainly Nikola Tesla helped Westinghouse to see why three phase alternating current was the winning way to transform the nation.
Tesla was correct in one thing, he recognized how cool alternating current and three phase electricity was, all while Edison was still trying to charge a battery.