These are just a few of the inventions that
Nikola Tesla devoloped.

The First Brushless A/C Motor
motor
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 Tesla was a huge fan of the work of Lord Faraday. Michael Faraday is generally credited with the discovery of electromagnetic induction. Faraday stated that the amount of power or electromotive force (EMF) produced on a closed path is directly proportional to the amount of magnetic flux on that path. Magnetic flux is the change in density of a magnet field moving through a fixed area.
(EMF)= -dIb
                             dt
,where Ib is the magnetic flux
Nikola Tesla applied his idea to make an A/C motor. The way the motor worked was by
surrounding a coil with current flowing through it with a magnetic field. The electromagnets, also known as the stator, that are stationary around the outside of the motor produce a magnetic field. The coils in the middle, also known as the armature, have a current flowing through them. The current in them is induced by the moving magnetic field. The interaction between the current and the magnetic field impart a torque on the armature and therefore the motor spins.

The First Hydroelectric Power Plant
In 1896 Nikola Tesla and George Westinghouse opened a monumental first. They opened a hydroelectric dam in Niagara Falls. This plant was a symbol of their victory against Thomas Edison in the "current wars." (Edison was trying to sell his idea of direct current) The opening and operation of the plant was a first step towards Tesla's of free power. The use of water as a renewable power source had been a dream of Tesla's since he was a child. The plant used the same principal
 falls
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that the A/C motors used. When power is applied to the motor it turns but when the motor is turned it produces power.

The First Radio Transmitter
boat
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 In 1898, in the old Madison Square Garden, Tesla presented something to the public which was at the time virtually unheard of...a radio controlled boat. His idea was to sell the technology to the military as a guided missile or torpedo. Today that technology is used for exactly that, although at the time the idea was not capitalized on. Tesla abandoned the idea of taking radio further for his ultimate ambition of transmitting power wirelessly. In his absence from the field another scientist, Guglielmo Marconi,
was able to develop the first radio and transmit the letter "s" across the Atlantic Ocean. At first Tesla had no problem with the fact the Marconi had seemingly undercut him. He is know for saying that he appreciated Marconi work because Marconi had used 17 of Tesla's patents to make the transmission. Later on when Marconi had won the Nobel Prize in physics Tesla had a few more sour grapes.