Early life:

• born in 1856 in what is now Yugoslavia
• his father was a pastor and wanted Nikola to joint the clergy
• Nikola loved math and physics and when he finished higher Realgymnasium persuaded his father to send him to a polytechnic school in Austria
• he left school in 1878 without finishing his degree (he set off a university in Prague but decided to quit and relieve his parents of the financial burden of his education).
• He worked as an electrician for a telephone company run by a family friend for four years and then when that disbanded for the Continental Edison Company in Paris.

• he had been thinking about a problem with electric motors, and he had an idea for a solution while strolling in a city park in Prague with a friend reciting Goethe's Faust (Tesla was recovering from a nervous breakdown at the time)
• he thought that some of the technical drawbacks of DC motors (sparking and the rapid wearing out of brushes) could be solved with an AC electric motor--he imagined in his mind a motor that needed no contact to carry the current to the moving parts
• he couldn't find backes so he moved to the U.S. in 1884 with a letter of recommendation from the manager of the Paris Edison company to Edison

• Telsa worked for a year for Edison on DC motors and voltage regulators (he left because he didn't get a bonus he had expected).  Tesla on Thomas A. Edison: "If Edison had a needle to find in a haystack, he would proceed at once with the diligence of the bee to examine straw after straw until he found the object of his search. I was a sorry witness of such doings, knowing that a little theory and calculation would have saved him ninety per cent of his labor." (New York Times, October 19, 1931)
• Then developed an improved arc light system for a group of NJ businessmen.  That was successful, but the businessmen bought him out and he was left without a proper job and ended up digging ditches.  His foreman heard he had an idea for an electrical motor and put him in touch with some investors.
• finally in 1887 he found backers in NY to finance a Tesla Electric Company to develop his AC motor .  he quickly perfected a promising new system of AC power generation, transmission, and utilization, called polyphase, leading to 7 patents in 1888 .  Polyphase uses two alternating currents, 90 degrees out of phase with each other, to power two electromagnets, creating a rotating field.  This induces a current in the armature, avoiding the connections that caused so much problems in DC motors.  Tesla did the necessary development to make his initial invention practical.

 Tesla inventions

• Westinghouse, who had previously invented an air brake for steam locomotives, had gotten interested in AC.  He initially bought an Italian transformer and a German AC generator (alternator) and began developing an AC incadenscent lighting system that would transmit AC power at high voltages to reduce transmission losses.
• Westinghouse and his staff developed more efficient transformers and alternators and marketed a very successful system--by 1891 Westinghouse was one of the three leading firms in electric lighting in the U.S.
• Meanwhile electric motors (DC) were coming into use in streetcars, and Westinghouse didn't have an AC motor for his system.
• Westinghouse bought Tesla's design: he paid $75,00 and $2.50/hp royalty that promised $30,000 the first three years and $15,000 in each succeeding year, and also hired Tesla.  Demonstrated the system at the 1893 Worlds Fair.
• Trouble was, Tesla had trouble adapting his motor to Westinghouse's AC lighting system, which used only single phase current.
• Everyone got discouraged: Tesla left Westinghouse in 1889 and work on the motor was abandoned for three years.  Then Westinghouse decided to go with polyphase, and developed Tesla's whole system, particularly for use at Niagara Falls .  A new more mathematically inclined generation of school-trained electrical engineers worked out the new systems.

• He then began investigating high-frequency, high-potential currents from a resonant transformer coil that later became known as the Tesla coil .  The Tesla coil is most fundamentally a new kind of transformer that uses a spark gap to transform a low-voltage, low-frequency current into a high-voltage, high-frequency one.   He found this intellectually appealing, but it was not a solution to an existing need.
• he patented the idea but did not seek commercial applications--instead he gave lectures about a new field of research.  These generated a lot of excitement for a while, in 1893 at a convention of the National Electric Light Association in St. Louis 5000 people attended his lecture.   He could light phosperescent gas-filled tubes without any wired connection.
• He was doing something closer to engineering science than invention, but he tended to present it in language that was more romantic than scientific.

 Tesla in Colorodo

• He dreamed big--the Tesla coil generated radio frequencies but Tesla wanted to use it to transmit not just information but power.
• He visualized a huge Tesla coil that would transmit electrical power anywhere on the planet.
• In 1899 he ran a pilot project in Colorado Springs where he generated sparks up to 135 feet long and conjectured that he transmitted electricity to the Indian ocean (meaning a traveler there could have illuminated a phosphorescent tube).   The transmitted energy also knocked out the Colorado Springs power station and caused it to catch on fire. ( source )
• In Colorado Springs, Tesla made what he regarded as his most important discovery-- terrestrial stationary waves . By this discovery he proved that the Earth could be used as a conductor and would be as responsive as a tuning fork to electrical vibrations of a certain frequency.
• He intended this to lead to a World Wireless Power system .   He lighted 200 lamps without wires from a distance of 25 miles (40 kilometres). At one time he was certain he had received signals from another planet in his Colorado laboratory, a claim that was met with derision in some scientific journals.
• in 1896 he lost his royalty from Westinghouse--GE and Westinghouse pooled their polyphase and railway patents in an attempt to raise the electrical industry out of an economic slump and Tesla was pressured into relinquishing his motor royalty.
• to replace the income he started to seek a commercial market for the Tesla coil.  He got $150,000 from J.P. Morgan in 1900 for a wireless telegraphy plant, and proceded to developed a power station on Long Island , that did not turn into an operating plant for either radio or power transmission.

 Tesla's Long Island Station

• he devised a scheme to broadcast electric power without wires using the Tesla coil, but he couldn't get support to develop it
• People did not even really understand his concept of broadcasting power--at this point radio is only used for point to point.

• he had always been eccentric, and became more so (read his Autobiography or here )
• wrote articles for the popular press to advance ideas of the future of electricity
• died in 1943 at the age of 86, penniless and relatively unrecognized
• now he is a hero on the web, see for example Tesla the Electric Magician
• some people think Tesla discovered a way to cause earthquakes that is being used as a secret weapon