Tesla gained experience in telephony and electrical engineering before emigrating to the United States in 1884 to work for Thomas Edison. He soon struck out on his own with financial backers, setting up laboratories/companies to develop a range of electrical devices. His patented ACinduction motor and transformer were licensed by George Westinghouse, who also hired Tesla as a consultant to help develop a power system using alternating current. Tesla is also known for his high-voltage, high-frequency power experiments in New York and Colorado Springs which included patented devices and theoretical work used in the invention of radio communication,for his X-ray experiments, and for his ill-fated attempt at intercontinental wireless transmission in his unfinished Wardenclyffe Tower project.
Tesla's achievements and his abilities as a showman demonstrating his seemingly miraculous inventions made him world-famous. Although he made a great deal of money from his patents, he spent a lot on numerous experiments. He lived for most of his life in a series of New York hotels although the end of his patent income and eventual bankruptcy led him to live in diminished circumstances.Tesla still continued to invite the press to parties he held on his birthday to announce new inventions he was working and make (sometimes unusual) statements.Because of his pronouncements and the nature of his work over the years, Tesla gained a reputation in popular culture as the archetypal "mad scientist".He died in room 3327 of the New Yorker Hotel on 7 January 1943.
Tesla's work fell into relative obscurity after his death, but since the 1990s, his reputation has experienced a comeback in popular culture.His work and reputed inventions are also at the center of many conspiracy theories and have also been used to support various pseudo sciences, UFO theories and New Age occultism. In 1960, in honor of Tesla, the General Conference on Weights and Measures for theInternational System of Units dedicated the term "tesla" to the SI unit measure for magnetic field strength.
Tesla's mother, Đuka Tesla (née Mandić), whose father was also a Serbian Orthodox priest, had a talent for making home craft tools, mechanical appliances, and the ability to memorize Serbian epic poems. Duka had never received a formal education. Nikola credited his eidetic memory and creative abilities to his mother's genetics and influence. Tesla's progenitors were from western Serbia, near Montenegro.
Tesla was the fourth of five children. He had an older brother named Dane and three sisters, Milka, Angelina and Marica. Dane was killed in a horse-riding accident when Nikola was five. Some accounts say that Tesla caused the accident by frightening the horse. In 1861, Tesla attended the "Lower" or "Primary" School in Smiljan where he studied German, arithmetic, and religion. In 1862, the Tesla family moved to Gospić, Austrian Empire, where Tesla's father worked as a pastor. Nikola completed "Lower" or "Primary" School, followed by the "Lower Real Gymnasium" or "Normal School".
In 1870, Tesla moved to Karlovac to attend school at Higher Real Gymnasium, where he was profoundly influenced by a math teacher Martin Sekulić.Tesla was able to perform integral calculus in his head, which prompted his teachers to believe that he was cheating. He finished a four-year term in three years, graduating in 1873.
In 1873, Tesla returned to his birthtown, Smiljan. Shortly after he arrived, Tesla contracted cholera; he was bedridden for nine months and was near death multiple times. Tesla's father, in a moment of despair, promised to send him to the best engineering school if he recovered from the illness(his father had originally wanted him to enter the priesthood).
In 1874, Tesla evaded being drafted into the Austro-Hungarian Army in Smiljan by running away to Tomingaj, near Gračac. There, he explored the mountains in hunter's garb. Tesla claimed that this contact with nature made him stronger, both physically and mentally. He read many books while in Tomingaj, and later claimed that Mark Twain's works had helped him to miraculously recover from his earlier illness.
In 1882, Tesla began working for the Continental Edison Company in France, designing and making improvements to electrical equipment.
In June 1884, Tesla relocated to New York City. During his trip across the Atlantic, his ticket, money, and some of his luggage were stolen, and he was nearly thrown overboard after a mutiny broke out on the ship. He arrived with only four cents in his pocket, a letter of recommendation, a few poems, and the remainder of his belongings.
In the letter of recommendation from Charles Batchelor, a former employer, to Thomas Edison, it is claimed that Batchelor wrote, "I know two great men and you are one of them; the other is this young man." (The exact contents of the letter are disputed in McNichol's book.) Edison hired Tesla to work for his Edison Machine Works. Tesla's work for Edison began with simple electrical engineering and quickly progressed to solving some of the company's most difficult problems. Tesla was even offered the task of completely redesigning the Edison Company's direct current generators.
In 1885, Tesla claimed that he could redesign Edison's inefficient motor and generators, making an improvement in both service and economy. According to Tesla, Edison remarked, "There's fifty thousand dollars in it for you—if you can do it"—this has been noted as an odd statement from an Edison whose company was stingy with pay and who did not have that sort of cash on hand.After months of work, Tesla fulfilled the task and inquired about payment. Edison, claiming that he was only joking, replied, "Tesla, you don't understand our American humor."Instead, Edison offered a US$10 a week raise over Tesla's US$18 per week salary; Tesla refused the offer and immediately resigned.
Tesla obtained around 300 patents worldwide for his inventions. Some of Tesla's patents are not accounted for, and various sources have discovered some that have laid hidden in patent archives. There are a minimum of 278 patents issued to Tesla in 26 countries that have been accounted for. Many of Tesla's patents were in the United States, Britain, and Canada, but many other patents were approved in countries around the globe. Many inventions developed by Tesla were not put into patent protection.