Nikola Tesla (10 July 1856 – 7 January 1943) was a<!-- PLEASE DO NOT CHANGE NATIONALITY OR ETHNICITY--> Serbian-American<!-- SEE Talk:Nikola Tesla/Nationality and ethnicity --> engineer, futurist, and inventor. He is known for his contributions to the design of the modern alternating current (AC) electricity supply system.
Born and raised in the Austro-Hungarian Empire, Tesla first studied engineering and physics in the 1870s without receiving a degree. He then gained practical experience in the early 1880s working in telephony and at Continental Edison in the new electric power industry. In 1884, he migrated to the United States, where he became a naturalized citizen. He worked for a short time at the Edison Machine Works in New York City before he struck out on his own. With the help of partners to finance and market his ideas, Tesla set up laboratories and companies in New York to develop a range of electrical and mechanical devices. His AC induction motor and related polyphase AC patents, licensed by Westinghouse Electric in 1888, earned him a considerable amount of money and became the cornerstone of the polyphase system, which Westinghouse marketed.
Tesla conducted a range of experiments with mechanical oscillators/generators, electrical discharge tubes, and early X-ray imaging among other things, in an attempt to develop inventions he could patent and market. He built a wirelessly controlled boat, one of the first wirelessly controlled vehicles ever produced. Tesla became well known as an inventor and demonstrated his achievements to celebrities and wealthy patrons at his lab. He was noted for his showmanship at public lectures. Throughout the 1890s, Tesla pursued his ideas for wireless lighting and worldwide wireless electric power distribution in his high-voltage, high-frequency power experiments in New York and Colorado Springs. In 1893, he made pronouncements on the possibility of wireless communication with his devices. Tesla tried to put these ideas to practical use in his unfinished Wardenclyffe Tower project, an intercontinental wireless communication and power transmitter, but ran out of funding before he could complete it.
After Wardenclyffe, Tesla experimented with a series of inventions in the 1910s and 1920s with varying degrees of success. Having spent most of his money, Tesla lived in a series of New York hotels, leaving behind unpaid bills. He died in New York City in January 1943. Tesla's work fell into relative obscurity following his death, until 1960, when the General Conference on Weights and Measures named the International System of Units (SI) measurement of magnetic flux density the tesla in his honor. There has been a resurgence in popular interest in Tesla since the 1990s. In 2013, Time named Tesla one of the 100 most significant figures of all time.
Early years<span class="anchor" id="Parents"></span>
<!--"Milutin Tesla" and "Đuka Mandić" redirect here.-->
Childhood
thumb|left|Tesla's rebuilt birth house (parish hall) and the church where his father served in [[Smiljan, Croatia|Smiljan. In his honor, the Nikola Tesla Memorial Center museum was established on the site.]]
Tesla was born on 10 July 1856 into a family of ethnic Serbs in Smiljan, a village then in the Military Frontier of the Austrian Empire and now in Croatia. His father, Milutin Tesla (1819–1879), was a priest of the Eastern Orthodox Church. His father's brother Josif was a lecturer at a military academy who wrote several textbooks on mathematics.
Tesla's mother, Georgina "Đuka" Mandić (1822–1892), whose father was also an Eastern Orthodox priest, had a talent for making home craft tools and mechanical appliances and the ability to memorize Serbian epic poems. Đuka had never received a formal education. Tesla credited his eidetic memory and creative abilities to his mother's genetics and influence.
Tesla was the fourth of five children. In 1861, Tesla attended primary school in Smiljan where he studied German, arithmetic, and religion. In 1862, the Tesla family moved to the nearby town of Gospić, where Tesla's father worked as parish priest. Nikola completed primary school, followed by middle school. Later in his patent applications, before he obtained American citizenship, Tesla would identify himself as "of Smiljan, Lika, border country of Austria-Hungary".
thumb|upright=.7|Tesla's father, Milutin, was an [[Eastern Orthodox Church|Orthodox priest in the village of Smiljan.|left]]
In 1870, Tesla moved to Karlovac to attend high school at the Higher Real Gymnasium where the classes were held in German. Tesla later wrote that he became interested in his physics professor's demonstrations of electricity. The "mysterious phenomena" made him want "to know more of this wonderful force". He was able to perform integral calculus in his head, prompting his teachers to believe that he was cheating. He finished a four-year term in three years, graduating in 1873.
After graduating, Tesla returned to Smiljan but soon contracted cholera, was bedridden for nine months and was near death several times. In a moment of despair, Tesla's father (who had originally wanted him to enter the priesthood), promised to send him to the best engineering school if he recovered from the illness. Tesla later said that he had read Mark Twain's earlier works while recovering from his illness.
Youth
The next year, Tesla evaded conscription into the Austro-Hungarian Army in Smiljan by running away southeast of Lika to Tomingaj, near Gračac. There he explored the mountains wearing hunter's garb. Tesla said that this contact with nature made him stronger, both physically and mentally. He enrolled at the Imperial-Royal Technical College in Graz in 1875 on a Military Frontier scholarship. Tesla passed nine exams (nearly twice as many as required) and received a letter of commendation from the dean of the technical faculty to his father, which stated, "Your son is a star of first rank." At Graz, Tesla was fascinated by the lectures on electricity presented by professor Jakob Pöschl. But by his third year, he was failing in school and never graduated, leaving Graz in December 1878. One biographer suggests Tesla was not studying and may have been expelled for gambling and womanizing.
thumb|upright=0.75|Tesla aged 23,
Tesla's family did not hear from him after he left school. There was a rumor among his classmates that he had drowned in the nearby river Mur, but in January one of them ran into Tesla in the town of Maribor and reported that encounter to Tesla's family. It turned out Tesla had been working there as a draftsman for 60 florins per month. In March 1879, Milutin finally located his son and tried to convince him to return home and take up his education in Prague. Tesla returned to Gospić later that month when he was deported for not having a residence permit. Tesla's father died the next month, on 17 April 1879, at the age of 60 after an unspecified illness.
In January 1880, two of Tesla's uncles paid for him to leave Gospić for Prague, where he was to study. He arrived too late to enroll at Charles-Ferdinand University; he had never studied Greek, a required subject; and he was illiterate in Czech, another required subject. He attended lectures in philosophy at the university as an auditor, but he did not receive grades for the courses.
Tesla moved to Budapest, Hungary, in 1881 to work under Tivadar Puskás at a telegraph company, the Budapest Telephone Exchange. Upon arrival, Tesla realized that the company, then under construction, was not functional, so he worked as a draftsman in the Central Telegraph Office instead. Within a few months, the Budapest Telephone Exchange became functional, and Tesla was allocated the chief electrician position. Tesla later described how he made many improvements to the Central Station equipment including an improved telephone repeater or amplifier.
Working at Edison
In 1882, Tivadar Puskás got Tesla another job in Paris with the Continental Edison Company. Tesla began working in what was then a brand new industry, installing indoor incandescent lighting citywide in large scale electric power utility. The company had several subdivisions and Tesla worked at the Société Electrique Edison, the division in the Ivry-sur-Seine suburb of Paris, in charge of installing the lighting system. There he gained a great deal of practical experience in electrical engineering. Management took notice of his advanced knowledge in engineering and physics, and soon had him designing and building improved versions of generating dynamos and motors.
Moving to the United States
thumb|Edison Machine Works on Goerck Street, New York. Tesla found the change from cosmopolitan Europe to working at this shop, located among the [[tenements on Manhattan's lower east side, a "painful surprise".]]
In 1884, Edison manager Charles Batchelor, who had been overseeing the Paris installation, was brought back to the United States to manage the Edison Machine Works, a manufacturing division situated in New York City, and asked that Tesla be brought to the United States as well. In June 1884, Tesla emigrated and began working almost immediately at the Machine Works on Manhattan's Lower East Side, an overcrowded shop with a workforce of several hundred machinists, laborers, managing staff, and 20 "field engineers" struggling with the task of building the large electric utility in that city. As in Paris, Tesla was working on troubleshooting installations and improving generators.
Historian W. Bernard Carlson notes Tesla may have met company founder Thomas Edison only a couple of times. Arc lighting was the most popular type of street lighting but it required high voltages and was incompatible with the Edison low-voltage incandescent system, causing the company to lose contracts in some cities. Tesla's designs were never put into production, possibly because of technical improvements in incandescent street lighting or because of an installation deal that Edison made with an arc lighting company.
Tesla had been working at the Machine Works for a total of six months when he quit. Later versions of this story have Thomas Edison himself offering and then reneging on the deal, quipping: "Tesla, you don't understand our American humor". The size of the bonus in either story has been noted as odd, since Machine Works manager Batchelor was stingy with pay, and the company did not have that amount of cash (equal to $ today) on hand. Tesla's diary contains just one comment on what happened at the end of his employment, a note he scrawled across the two pages covering 7 December 1884, to 4 January 1885, saying "Good By to the Edison Machine Works".
AC and the induction motor
thumb|upright|Drawing from , illustrating the principle of Tesla's alternating current induction motor
In late 1886, Tesla met Alfred S. Brown, a Western Union superintendent, and New York attorney Charles Fletcher Peck. The two men were experienced in setting up companies and promoting inventions and patents for financial gain. Based on Tesla's new ideas for electrical equipment, including a thermo-magnetic motor idea, they agreed to back the inventor financially and handle his patents. Together they formed the Tesla Electric Company in April 1887, with an agreement that profits from generated patents would go to Tesla, to Peck and Brown, and to fund development. They set up a laboratory for Tesla at 89 Liberty Street in Manhattan, where he worked on improving and developing new types of electric motors, generators, and other devices.
In 1887, Tesla developed an induction motor that ran on alternating current (AC), a power system format that was rapidly expanding in Europe and the United States because of its advantages in long-distance, high-voltage transmission. The motor used polyphase current, which generated a rotating magnetic field to turn the motor (a principle that Tesla claimed to have conceived in 1882). This innovative electric motor, patented in May 1888, was a simple self-starting design that did not need a commutator, thus avoiding sparking and the high maintenance of constantly servicing and replacing mechanical brushes.
Along with getting the motor patented, Peck and Brown arranged to get the motor publicized, starting with independent testing to verify it was a functional improvement, followed by press releases sent to technical publications for articles to run concurrently with the issue of the patent. Physicist William Arnold Anthony (who tested the motor) and Electrical World magazine editor Thomas Commerford Martin arranged for Tesla to demonstrate his AC motor on 16 May 1888 at the American Institute of Electrical Engineers. Engineers working for the Westinghouse Electric & Manufacturing Company reported to George Westinghouse that Tesla had a viable AC motor and related power system—something Westinghouse needed for the alternating current system he was already marketing. Westinghouse looked into getting a patent on a similar commutator-less, rotating magnetic field-based induction motor developed in 1885 and presented in a paper in March 1888 by Italian physicist Galileo Ferraris, but decided that Tesla's patent would probably control the market.
thumb|right|upright|Tesla's AC dynamo-electric machine (AC [[electric generator) in an 1888 ]]
In July 1888, Brown and Peck negotiated a licensing deal with George Westinghouse for Tesla's polyphase induction motor and transformer designs for $60,000 in cash and stock and a royalty of $2.50 per AC horsepower produced by each motor. Westinghouse also hired Tesla for one year for the large fee of $2,000 ($ in today's dollars) per month to be a consultant at the Westinghouse Electric & Manufacturing Company's Pittsburgh labs.
During that year, Tesla worked in Pittsburgh, helping to create an alternating current system to power the city's streetcars. He found it a frustrating period because of conflicts with the other Westinghouse engineers over how best to implement AC power. Between them, they settled on a 60-cycle AC system that Tesla proposed (to match the working frequency of Tesla's motor), but they soon found that it would not work for streetcars, since Tesla's induction motor could run only at a constant speed. They ended up using a DC traction motor instead.
Market turmoil
Tesla's demonstration of his induction motor and Westinghouse's subsequent licensing of the patent, both in 1888, came at the time of extreme competition between electric companies. The three big firms, Westinghouse, Edison, and Thomson-Houston Electric Company, were trying to grow in a capital-intensive business while financially undercutting each other. There was even a "war of currents" propaganda campaign going on, with Edison Electric claiming their direct current system was better and safer than the Westinghouse alternating current system and Thomson-Houston sometimes siding with Edison. Competing in this market meant Westinghouse would not have the cash or engineering resources to develop Tesla's motor and the related polyphase system right away.
Two years after signing the Tesla contract, Westinghouse Electric was in trouble. The near collapse of Barings Bank in London triggered the financial panic of 1890, causing investors to call in their loans to Westinghouse Electric. The sudden cash shortage forced the company to refinance its debts. The new lenders demanded that Westinghouse cut back on what looked like excessive spending on acquisition of other companies, research, and patents, including the per motor royalty in the Tesla contract. At that point, the Tesla induction motor had been unsuccessful and was stuck in development. Westinghouse was paying a $15,000-a-year guaranteed royalty even though operating examples of the motor were rare and polyphase power systems needed to run it were even rarer.
In early 1891, George Westinghouse explained his financial difficulties to Tesla in stark terms, saying that, if he did not meet the demands of his lenders, he would no longer be in control of Westinghouse Electric and Tesla would have to "deal with the bankers" to try to collect future royalties. The advantages of having Westinghouse continue to champion the motor probably seemed obvious to Tesla and he agreed to release the company from the royalty payment clause in the contract. Six years later Westinghouse purchased Tesla's patent for a lump sum payment of $216,000 as part of a patent-sharing agreement signed with General Electric (a company created from the 1892 merger of Edison and Thomson-Houston).
New York laboratories
thumb|alt=Mark Twain in Tesla's lab, 1894|[[Mark Twain in Tesla's South Fifth Avenue laboratory, 1894]]
The money Tesla made from licensing his AC patents made him independently wealthy and gave him the time and funds to pursue his own interests. In 1889, Tesla moved out of the Liberty Street shop Peck and Brown had rented and for the next dozen years worked out of a series of workshop/laboratory spaces in Manhattan. These included a lab at 175 Grand Street (1889–1892), the fourth floor of 33–35 South Fifth Avenue (1892–1895), and sixth and seventh floors of 46 & 48 East Houston Street (1895–1902).
Tesla coil
In the summer of 1889, Tesla traveled to the 1889 Exposition Universelle in Paris and learned of Heinrich Hertz's 1886–1888 experiments that proved the existence of electromagnetic radiation, including radio waves. In repeating and then expanding on these experiments, Tesla tried powering a Ruhmkorff coil with a high speed alternator he had been developing as part of an improved arc lighting system but found that the high-frequency current overheated the iron core and melted the insulation between the primary and secondary windings in the coil. To fix this problem, Tesla came up with his "oscillating transformer", with an air gap instead of insulating material between the primary and secondary windings and an iron core that could be moved to different positions in or out of the coil. Later called the Tesla coil, it would be used to produce high-voltage, low-current, high frequency alternating-current electricity. He would use this resonant transformer circuit in his later wireless power work.
Wireless lighting
thumb|right|Tesla demonstrating wireless lighting by "electrostatic induction" during an 1891 lecture at [[Columbia College (New York)|Columbia College via two long Geissler tubes (similar to neon tubes) in his hands]]
After 1890, Tesla experimented with transmitting power by inductive and capacitive coupling using high AC voltages generated with his Tesla coil. He attempted to develop a wireless lighting system based on near-field inductive and capacitive coupling and conducted a series of public demonstrations where he lit Geissler tubes and even incandescent light bulbs from across a stage. He spent most of the decade working on variations of this new form of lighting with the help of various investors but none of the ventures succeeded in making a commercial product out of his findings.
In 1893 at St. Louis, Missouri, the Franklin Institute in Philadelphia, Pennsylvania and the National Electric Light Association, Tesla told onlookers that he was sure a system like his could eventually conduct "intelligible signals or perhaps even power to any distance without the use of wires" by conducting it through the Earth.
On 30 July 1891, aged 35, Tesla became a naturalized citizen of the United States. In the same year, he patented his Tesla coil.
He served as a vice-president of the American Institute of Electrical Engineers from 1892 to 1894, the forerunner of the modern-day Institute of Electrical and Electronics Engineers (IEEE) (along with the Institute of Radio Engineers).
Polyphase system and the Columbian Exposition<span class="anchor" id="The "Tesla Polyphase System""></span>
thumbnail|A Westinghouse display of the "Tesla Polyphase System" at Chicago's 1893 Columbian Exposition
By the beginning of 1893, Westinghouse engineer Charles F. Scott and then Benjamin G. Lamme had made progress on an efficient version of Tesla's induction motor. Lamme found a way to make the polyphase system it would need compatible with older single-phase AC and DC systems by developing a rotary converter. Westinghouse Electric now had a way to provide electricity to all potential customers and started branding their polyphase AC system as the "Tesla Polyphase System". They believed that Tesla's patents gave them patent priority over other polyphase AC systems.
Westinghouse Electric asked Tesla to participate in the 1893 World's Columbian Exposition in Chicago where the company had a large space in the "Electricity Building" devoted to electrical exhibits. Westinghouse Electric won the bid to light the Exposition with alternating current and it was a key event in the history of AC power, as the company demonstrated to the American public the safety, reliability, and efficiency of an alternating current system that was polyphase and could also supply the other AC and DC exhibits at the fair.
A special exhibit space was set up to display various forms and models of Tesla's induction motor. The rotating magnetic field that drove them was explained through a series of demonstrations including an Egg of Columbus that used the two-phase coil found in an induction motor to spin a copper egg making it stand on end.
Tesla visited the fair for a week during its six-month run to attend the International Electrical Congress and put on a series of demonstrations at the Westinghouse exhibit. A specially darkened room had been set up where Tesla showed his wireless lighting system, using a demonstration he had previously performed throughout America and Europe; these included using high-voltage, high-frequency alternating current to light wireless gas-discharge lamps.
Steam-powered oscillating generator
During his presentation at the International Electrical Congress in the Columbian Exposition Agriculture Hall, Tesla introduced his steam-powered reciprocating electricity generator that he patented that year, something he thought was a better way to generate alternating current. Steam was forced into the oscillator and rushed out through a series of ports, pushing a piston up and down that was attached to an armature. The magnetic armature vibrated up and down at high speed, producing an alternating magnetic field. This induced alternating electric current in the wire coils located adjacent. It did away with the complicated parts of a steam engine/generator, but never caught on as a feasible engineering solution to generate electricity.
Consulting on Niagara
In 1893, Edward Dean Adams, who headed the Niagara Falls Cataract Construction Company, sought Tesla's opinion on what system would be best to transmit power generated at the falls. Over several years, there had been a series of proposals and open competitions on how best to do it. Among the systems proposed by several U.S. and European companies were two-phase and three-phase AC, high-voltage DC, and compressed air. Adams asked Tesla for information about the current state of all the competing systems. Tesla advised Adams that a two-phased system would be the most reliable and that there was a Westinghouse system to light incandescent bulbs using two-phase alternating current. The company awarded a contract to Westinghouse Electric for building a two-phase AC generating system at the Niagara Falls, based on Tesla's advice and Westinghouse's demonstration at the Columbian Exposition. At the same time, a further contract was awarded to General Electric to build the AC distribution system.
The Nikola Tesla Company
In 1895, Edward Dean Adams, impressed with what he saw when he toured Tesla's lab, agreed to help found the Nikola Tesla Company, set up to fund, develop, and market a variety of previous Tesla patents and inventions as well as new ones. Alfred Brown signed on, bringing along patents developed under Peck and Brown. The board was filled out with William Birch Rankine and Charles F. Coaney.
On 13 March 1895, the South Fifth Avenue building that housed Tesla's lab caught fire. It started in the basement of the building and was so intense Tesla's fourth-floor lab burned and collapsed into the second floor. The fire set back Tesla's ongoing projects, and destroyed a collection of early notes and research material, models, and demonstration pieces, including many that had been exhibited at the 1893 Worlds Colombian Exposition. Tesla told The New York Times "I am in too much grief to talk. What can I say?"
X-ray experimentation
left|thumb|upright|Tesla took this x-ray of his hand.
Starting in 1894, Tesla began investigating what he referred to as radiant energy of "invisible" kinds after he had noticed damaged film in his laboratory in previous experiments (later identified as "Roentgen rays" or "X-rays"). His early experiments were with Crookes tubes, a cold cathode electrical discharge tube. Tesla may have inadvertently captured an X-ray image—predating, by a few weeks, Wilhelm Röntgen's December 1895 announcement of the discovery of X-rays—when he tried to photograph Mark Twain illuminated by a Geissler tube, an earlier type of gas discharge tube. The only thing captured in the image was the metal locking screw on the camera lens.
In March 1896, Tesla conducted experiments in X-ray imaging, developing a high-energy single-terminal vacuum tube that had no target electrode and that worked from the output of the Tesla coil (the modern term for the phenomenon produced by this device is bremsstrahlung or braking radiation). In his research, Tesla devised several experimental setups to produce X-rays. Tesla held that, with his circuits, the "instrument will ... enable one to generate Roentgen rays of much greater power than obtainable with ordinary apparatus".
Tesla noted the hazards of working with his circuit and single-node X-ray-producing devices. In his many notes on the early investigation of this phenomenon, he attributed the skin damage to various causes. He believed early on that damage to the skin was not caused by the Roentgen rays, but by the ozone generated in contact with the skin, and to a lesser extent, by nitrous acid. Tesla incorrectly believed that X-rays were longitudinal waves, such as those produced in waves in plasmas. These plasma waves can occur in force-free magnetic fields.
Radio remote control
thumb|upright|In 1898, Tesla demonstrated a radio-controlled boat, which he hoped to sell as a guided torpedo to navies around the world.
In 1898, Tesla demonstrated a boat that used a coherer-based radio control—which he dubbed "telautomaton"—to the public during an electrical exhibition at Madison Square Garden. Tesla tried to sell his idea to the U.S. military as a type of radio-controlled torpedo, but they showed little interest. Tesla took the opportunity to further demonstrate "Teleautomatics" in an address to a meeting of the Commercial Club in Chicago, while he was traveling to Colorado Springs, on 13 May 1899.
Wireless power
thumb|upright|left|Tesla sitting in front of a spiral coil used in his wireless power experiments at his East Houston St. laboratory
From the 1890s through 1906, Tesla spent a great deal of his time and fortune on a series of projects trying to develop the transmission of electrical power without wires. At the time, there was no feasible way to wirelessly transmit communication signals over long distances, let alone large amounts of power. Tesla had studied radio waves early on, and came to the conclusion that part of the existing study on them, by Hertz, was incorrect.