Nikola Tesla

Tesla was born "at the stroke of midnight" with lightning striking during a summer storm. He was born in Smiljani near Gospiæ, Lika, (the Krajina, a military district of Austro-Hungarian Empire, now in Croatia). The midwife commented, "He'll be a child of the storm," to which his mother replied, "No, of light." Tesla was baptised in the Old Slavonic Church rite. His Baptism Certificate reports that he was born on June 28 (Julian calendar; July 10 in the Gregorian calendar), and christened by the Serb orthodox priest, Toma Oklobd'ija.

His Serb father, Reverend Milutin Tesla, was a priest in the Orthodox Metropolitanate of Karlovci which gathered to Serbs of the "Greek-rite" as they were legally referred to in Austria-Hungary at the time. His mother, Djuka Mandic, from a prominent Serb family of the Banija, made home craft tools. He was one of five children, having one brother and three sisters. His godfather, Jovan Drenovac, was a Captain in the Krajina army. His family moved to Gospiæ in 1862. Tesla went to school in Karlovac (Austria-Hungary), then studied electrical engineering at the Austria Politechnic in Graz, Austria (1875). While there, he studied the uses of alternating current. He also developed a telephone repeater (or amplifier).

In 1881 he moved to Budapest to work for the telegraph company, American Telephone Company. On the opening of the telephone exchange in Budapest, 1881, Tesla became the chief electrician to the telephone company, later engineer to the Yugoslav government and the country's first telephone system. Tesla invented a precursor to modern wireless telephone, known as a telephone repeater (or sometimes a amplifier). The device could act as a audio speaker (not a audio transducer). The device had its resonance tuned to a particular frequency of other repeaters to communicate between each. In 1916, Tesla described the prior developed audio transducers. According to Tesla, it was the "... [S]implest ways [to detect the radiant energy ...] the low frequency gave audible notes. [... in a field, there was] placed a conductor, a wire or a coil, and then Tesla would get a note [...] characteristics of the audible note". The audible sounds were of the quality of the telephones diaphragms of that period of time. The invention was never patented nor released publicly (till years later by Tesla himself). The device also contained the characteristics of modern wireless telephones.

For a while he stayed in Maribor. He was employed at his first job as an assistant engineer. Tesla suffered a nervous breakdown during this time. In 1882 he moved to Paris to work as an engineer for the Continental Edison Company. He worked designing improvements to electric equipment. In the same year, Tesla conceived of the induction motor and began developing various devices that use rotating magnetic fields (for which he received patents in 1888). Tesla visualized the rotating fields and thereby designed the induction motor. Tesla hastened from Paris to his mother's side as she lay dying, arriving hours before her death in 1882. Her last words were to him were, "You've arrived, Nidzo, my pride." After her death, Tesla fell ill. He spent two to three weeks recuperating in Gospiæ and Tomingaj. All his life, Tesla kept a home-spun embroidered travel bag from his mother.

Middle years
In 1884, leaving the warfare of his birthplace behind, Tesla moved to the United States of America to accept a job with the Edison Company in New York City. He arrived in the US with 4 cents to his name, a book of poetry, and a letter of recommendation (from Charles Batchelor, his manager in his previous job).

Early employment
Tesla worked for Thomas Edison for a time. Edison offered him $50,000 for improvements in Edison's DC dynamos. Tesla worked nearly a year to redesign the inferior construction. Upon returning to Edison and inquiring about the $50,000, Edison replied, "Tesla, you don't understand our American humor." Tesla resigned. In 1886, Tesla formed his own company, Tesla Electric Light & Manufacturing. The initial financial investors disagreed with Tesla on his plan for an alternating current motor and eventually relieved Tesla of his duties at the company. Tesla was unemployed for a time.

Tesla worked on a New York street gang, as a laborer, from 1886 to 1887 to raise capital to eat and for his next project. In 1887, he constructed the initial brushless alternate-current induction motor. He demonstrated the brushless two-phase one-fifth horsepower (150 W) induction motor to the American Institute of Electrical Engineers (now IEEE) in 1888. Also in 1888, he developed the principles of his Tesla coil. In the same period, he began working with Westinghouse, Westinghouse's Pittsburgh labs. Westinghouse listened to Tesla's ideas for polyphase systems. These systems would allow alternating current [AC] electricity to be transmitted over large distances.

X-rays and friendships
In April 1887, Tesla began investigating what would later be called X-rays using his own devices as well as Crookes tubes. He did this by experimenting with high voltages and vacuum tubes. His technical publications indicate that he invented and developed a special single-electrode X-ray tube. Tesla's tubes differed from other X-ray tubes in that they had no target electrode. He stated these facts in his 1897 X-ray lecture before the New York Academy of Sciences. The modern term for this is the bremsstrahlung process, in which a high-energy secondary X-ray emission is produced when charged particles (such as electrons) pass through matter.

In 1891, Tesla became a naturalized American citizen. Also in this year, Tesla established his Houston Street laboratory in New York. He lit vacuum tubes wirelessly in the lab, providing evidence for the potential of wireless power transmission. Around this time, Tesla developed a close and lasting friendship with author and humorist Mark Twain. They spent quite a bit of time together in Tesla's lab and other areas. Tesla's closest friends were writers and artists. Tesla's also befriended R. A. Jonson, who adapted several poems of the Serbian poet Jovan Jovanoviæ Zmaj (and which were translated into English by Tesla).

When he was 36 years old, the first patents concerning the polyphase power system were granted. He continued researching rotating magnetic field principles and polyphase power distribution. By 1892, Tesla became aware of certain characteristics later identified by Wilhelm Conrad Röntgen as effects of X-rays. He performed several experiments (including taking photographs of the bones of his hand) but did not make his findings widely known. Much of his research was lost in the 1895 Houston Street lab fire. He did obtain pictures of the human body with X-rays and subsequently sent the images to Röntgen. His later X-ray experimentation by vacuum high field emissions led him to alert the scientific community first to the biological hazards associated with X-ray exposure.

Wireless and the AIEE
Tesla served as the Vice-President of AIEE, the American Institute of Electrical Engineers (now part of the IEEE) from 1892 to 1894. From 1893 to 1895, Tesla investigated high frequency alternating currents. He generated one million volts of alternating currents using a conical Tesla coil. He developed the skin effect in circuitry, designed tuned circuits, invented a machine for inducing sleep, cordless gas discharge lamps, and transmitted electromagnetic energy without wires, effectively building the first radio transmitter.

In St. Louis, Missouri, Tesla made the first public demonstration of radio communication in 1893. Addressing the Franklin Institute in Philadelphia, Pennsylvania and the National Electric Light Association, he described and demonstrated in detail the principles of radio communication. The apparatus he used contained all the elements that were incorporated into radio systems before the development of the vacuum tube.

World's Fair Exposition
Main article: World Columbian Exposition
At the 1893 World's Fair, the World Columbian Exposition, in Chicago, Illinois, celebrating the 400th anniversary of Christopher Columbus' first voyage to America, an international exposition was held, in which, for the first time, a building was devoted to electrical exhibits. It was a historic event and the beginning of a revolution as Tesla and Westinghouse introduced visitors to AC power by providing AC energy to illuminate the World Columbian Exposition. The public at large observed firsthand the qualities and abilities of AC power. All the exhibits were from commercial enterprises. Edison, Brush, Western Electric, and Westinghouse all had exhibits. General Electric Company (backed by Edison and J.P. Morgan) proposed to power the electric fair with direct current at the cost of one million dollars.

Westinghouse proposed, armed with Tesla's AC system, to illuminate the exposition for half as much. Tesla's high-frequency high-voltage lighting produced more efficient light with less heat. A two-phase induction motor was driven by current from the main generators to power the system. Edison tried to prevent the use of his light bulbs with Tesla's system. GE banned the use of Edison's lamps in Westinghouse's exhibits. Still, Westinghouse's proposal was chosen over the inferior DC system to power the fair.

Westinghouse displayed several polyphase systems. The exhibits included a switchboard, polyphase generators, step-up and step-down transformers, transmission line, commercial size induction motors, commercial size synchronous motors, and rotary direct current converters (one of which was operating a railway motor). The working-scale system allowed the public a view of a system of polyphase power which could transmit long distances. Meters and other auxiliary devices were also present.

Tesla displayed the first neon light tubes at the exposition, demonstrating his phosphorescent lighting powered without wires by high-frequency fields. Tesla's lighting inventions exposed to high-frequency currents would bring the gases to incandescence. Tesla displayed the first practical phosphorescent lamps (a precursor to fluorescent lamps). His innovations in this type of light emission were not regularly patented.

Also in the exhibits were Tesla's demonstrations, most notably the "Egg of Columbus". This device explains the principles of the rotating magnetic field and his induction motor. The Egg consisted of a polyphase field coil underneath a plate with a copper egg positioned over the top. When the sequence of the coils were energized, the magnetic field arrangement inductively created a rotation on the egg and made it stand up on end (appearing to resist gravity).

On August 25, Elisha Gray introduced Tesla for the delivery of a lecture on mechanical and electrical oscillators. Tesla explained his work for efficiently increasing the work at high frequency of reciprocation. As Electrical Congress members listened, Tesla delineated mechanisms which could produce oscillations of constant periods irrespective of the pressure applied and irrespective of frictional losses and loads. He explained the working means of producing constant period electric currents (not resorting to spark gaps or breaks) and how to produce these with reliable mechanisms.

The Exposition's illumination with electricity using Tesla's and Westinghouse's alternate current removed any doubt of the utility of the polyphase alternating current.

War of currents
Main article:War of Currents
During this time, direct current was the standard, and Edison was not disposed to lose all his patent royalties to a former employee. Adversaries due to Edison's promotion of DC for electric power distribution over the more efficient alternating current advocated by Tesla, Edison (or, reportedly, one of his employees) employed the tactics of misusing Tesla's patents to construct the first electric chair for the state of New York in order to promote the idea that alternating currents were deadly.

In his work with the rotary magnetic fields, Tesla devised the system for transmission of power over long distances. He partnered with George Westinghouse to commercialize this system. Westinghouse had previously bought the rights to Tesla's polyphase patents and other patents for AC transformers. Experts announced proposals to harness the Niagara Falls for generating electricity. Against General Electric and Edison's proposal, Tesla's AC system won the international Niagara Falls Commission contract. The commission was led by Lord Kelvin and backed by entrepreneurs (such as J.P. Morgan, Lord Rothschild, and John Jacob Astor). Work began in 1893 on the Niagara Falls generation project and Tesla's technology was applied to generate electromagnetic energy from the falls.

Some doubted that the system would generate enough electricity to power industry in Buffalo. Tesla was sure it would work, saying that Niagara Falls had the ability to power the entire eastern U.S. On November 16, 1896, the first transmission of electrical power between two cities was sent from Niagara Falls to industries in Buffalo from the first commercial two-phase power plants (known as hydroelectric generators) at the Edward Dean Adams Station.

The hydroelectric generators were built by Westinghouse Electric Corporation from Tesla's AC system patent designs. Tesla's system designs alleviated the limitations of the previous DC methods. The nameplates on the generators bear Tesla's name. He also set the 60 hertz standard for North America. It took five years to complete the whole facility.

With the financial backing of George Westinghouse, Tesla's AC replaced DC, enormously extending the range and improving the safety and efficiency of power distribution. Tesla's Niagara Falls system marked the end of Edison's roadmap for electrical transmission. Eventually, Edison's GE company converted to the AC system. Tesla's contributions to the modern world are widely regarded as more important and long-lasting, by some, than those of his nemesis and one-time employer, Thomas Edison.