Sir John Ambrose Fleming (29 November 1849 – 18 April 1945) was an English electrical engineer and physicist. He is known for inventing the vacuum tube radio transmitter—with which the first transatlantic radio transmission was made—and establishing the right-hand rule used in physics.
Biography
Early life John Ambrose Fleming was born on 29 November 1849 in Lancaster, England, the eldest of seven children of James Fleming DD, a Congregational minister at High Street Congregational Chapel, and Mary Ann White. He was baptised on 11 February 1850. Through his mother, Fleming was the nephew of Ellen Ranyard (née White), founder of The London Bible and Domestic Female Mission, and Edward White, a Free Church minister. Sometime between 1853 and 1854, the Fleming family moved to North London. Initially tutored by his mother, Fleming enrolled at University College School in 1863, where he developed an interest in engineering. Unable to afford the fees to be apprenticed with a professional engineer, he decided to pursue a career in science teaching.
Education In 1867, Fleming enrolled at University College London, where he studied under Augustus De Morgan, Alexander Williamson, and George Carey Foster. However in 1868, he temporarily suspended his studies due to financial difficulties. He subsequently spent four months at a shipbuilders drawing office in Dublin before finding employment at a City stockbroker's office. He continued his studies on a part time basis, and graduated with a B.Sc. in 1870. Following graduation, Fleming took a position teaching science at the Rossall School upon the recommendation of Edward Frankland. In 1872, he enrolled at the Royal College of Science, where he studied chemistry under Frankland. There he first studied Alessandro Volta's battery, which became the subject of his first scientific paper. His paper was the first read at the inaugural meeting of the Physical Society of London in 1874. The same year, Fleming returned to teaching, and was appointed Science Master at Cheltenham College. In 1877, he enrolled at St John's College, Cambridge, to study the Natural Science Tripos. From January 1878 until May 1879, he was one of two students who attended the finial lectures of James Clerk Maxwell. In the summer of 1879, he obtained a D.Sc. from the University of London. In early 1880, he graduated with First Class Honours from St John's College, where he became a Fellow in 1883.
Career
Fleming served for one year at Cambridge University as a demonstrator of mechanical engineering, before being appointed the first Professor of Physics and Mathematics at University College Nottingham, but he left after less than a year. In 1882, he became an electrician at the Edison Electric Light Company, advising on lighting systems and the new Ferranti alternating current systems. In 1885, Fleming became head of the newly established Department of Electrical Technology at University College London. Although this offered great opportunities, he recalls in his autobiography that the only equipment provided to him was a blackboard and piece of chalk. In 1897, the Pender Memorial Committee donated £5,000 to the Department, which was used to found the Pender Laboratory—along with the Pender Chair, which Fleming took up. In 1926, Fleming retired from University College London. He remained active, becoming a committed advocate of the new technology of television which included serving as the second President of the Television Society. His contributions to electronic communications and radar were of vital importance in winning World War II.
Inventions
Radio transmitter In 1899, Guglielmo Marconi, the inventor of radiotelegraphy, decided to attempt transatlantic radio communication. This would require a scale-up in power from the small 200–400 watt transmitters he had used up to then. Marconi contracted Fleming, an expert in power engineering, to design a radio transmitter. He designed the world's first large radio transmitter, a complicated spark transmitter powered by a 25 kW alternator driven by a combustion engine—built at Poldhu, Cornwall—which transmitted the first radio transmission across the Atlantic on 12 December 1901. Although Fleming was responsible for the design, the director of the Marconi Company had made him agree that: "If we get across the Atlantic, the main credit will be and must forever be Mr. Marconi's". Accordingly, the worldwide acclaim that greeted this landmark accomplishment went to Marconi, who only credited Fleming along with several other Marconi employees, saying he did some work on the "power plant". Marconi also forgot a promise to give him 500 shares of Marconi stock if the project was successful; he was bitter about this treatment. He honoured his agreement and did not speak about it throughout Marconi's life, but after his death in 1937 said Marconi had been "very ungenerous".
Fleming valve In 1904, while working for the Marconi Company to improve transatlantic radio reception, Fleming built the first vacuum tube—the two-electrode diode—which he called the "oscillation valve", for which he received a patent on 16 November. It became known as the Fleming valve. The Supreme Court of the United States later invalidated the patent because of an improper disclaimer and, additionally, maintained the technology in the patent was known art when filed. This invention of the vacuum tube is often considered to have been the beginning of electronics. Fleming's diode was used in radio receivers and radar for many decades afterwards, until it was superseded by solid-state electronic technology more than 50 years later.
Patent dispute
In 1906, American inventor Lee De Forest added a control grid to the valve to create an amplifying vacuum tube RF detector called the Audion, leading Fleming to accuse him of infringing on his patents. De Forest's tube developed into the triode, the first electronic amplifier. The triode was vital in the creation of long-distance telephone and radio communications, radars, and early electronic digital computers (mechanical and electromechanical digital computers already existed using different technology). The court battle over these patents lasted for many years with victories at different stages for both sides.
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