JOHN AMBROSE FLEMING

'Sir John Ambrose Fleming' (November 29, 1849 - April 18, 1945) was an English electrical engineer and physicist. He was born on November 29 1849, the eldest of seven children of James Fleming DD (d. 1879), a Congregational minister, and his wife, Mary Ann, at Lancaster, Lancashire and baptised on February 11 1850. He was a devout Christian and preached on one occasion at St Martin-in-the-Fields in London on the topic of evidence for the resurrection. In 1932, along with Douglas Dewar and Bernard Acworth, he helped establish the Evolution Protest Movement. Having no children, he bequeathed much of his estate to Christian charities, especially those that helped the poor. He was an accomplished photographer and, in addition, he painted watercolours and enjoyed climbing in the Alps.

Contents

Early years

Education and marriages

Activities and achievements

Books by Fleming

References

External articles

Early years

Ambrose Fleming was born in Lancaster and educated at the University College School, London, and the University College London. He became a Lecturer at a number of universities including the University of Cambridge, the University of Nottingham, and University College London, where he was the first professor of Electrical Engineering. Consultant to the Marconi Wireless Telegraph Company, Swan, Ferranti, Edison Telephone, and later the Edison Electric Light Company. In 1892, Fleming presented an important paper on electrical transformer theory to the Institution of Electrical Engineers in London.

Education and marriages

Fleming started school at about the age of ten, attending a private school where he particularly enjoyed geometry. Prior to that his mother tutored him and he had learned, virtually by heart, a book called the ''Child's Guide to Knowledge'', a popular book of the day - even as an adult he would quote from it. His schooling continued at the University College School where, although accomplished at maths, he habitually came bottom of the class at Latin.
Even as a boy he wanted to become an engineer. At 11 he had his own workshop where he built model boats and engines. He even built his own camera, the start of a lifelong interest in photography. Training to become an engineer was beyond the family's financial resources, but he reached his goal via a path that alternated education with work.
He enrolled for a BSc degree at University College, London, graduated in 1870, and studied under the mathematician Augustus de Morgan and the physicist G. Carey Foster. He became a student of chemistry at the Royal College of Science in South Kensington in London (now Imperial College). There he first studied the voltaic battery, which became the subject of his first scientific paper. This was the first paper to be read to the new Physical Society of London (now the Institute of Physics) and appears on page one of volume one of their Proceedings. Financial problems again forced him to work for his living and in the summer of 1874 he became science master at Cheltenham College, a public School, earning £400 per year. His own scientific research continued and he corresponded with James Clerk Maxwell at Cambridge University. After saving £400, and securing a grant of £50 a year, in October 1877 he once again enrolled as a student, this time at Cambridge. He was now 28 years old. Maxwell's lectures, he admitted, were difficult to follow. Maxwell, he said, often appeared obscure and had 'a paradoxical and allusive way of speaking'. On occasions Fleming was the only student at those lectures. Fleming again graduated, this time with a first in chemistry and physics. He then obtained a DSc from London and served one year at Cambridge University as a demonstrator of mechanical engineering before being appointed as the first Professor of Physics and Mathematics at the University of Nottingham. But after less than a year he left.
On 11 June 1887 he married Clara Ripley (1856/7–1917), daughter of Walter Freake Pratt, a solicitor from Bath. On 27 July 1928 he married the popular young singer Olive May Franks (b. 1898/9), of Bristol, daughter of George Franks, a Cardiff businessman.

Activities and achievements

In November 1904, he invented and patented the two-electrode vacuum-tube rectifier, which he called the oscillation valve. It was also called a thermionic valve, vacuum diode, kenotron, thermionic tube, or Fleming valve. The Supreme Court later invalidated the patent because of an improper disclaimer and, additionally, maintained the technology in the patent was known art when filed.^[1] This invention is often considered to have been the beginning of electronics, for this was the first vacuum tube. Fleming's diode was used in radio receivers and radars for many decades afterwards, until solid-state electronic technology took over more than 50 years later.
In 1906, Lee De Forest of the U.S. added a control "grid" to the valve to create a vacuum tube RF detector called the ''Audion'', leading Fleming to accuse him of copying his ideas. De Forest's device was shortly refined by him and Edwin H. Armstrong into an amplifier tube called the triode. The triode was vital in the creation of long-distance telephone and radio communications, radars, and early electronic digital computers (mechanical and electro-mechanical digital computers already existed using different technology). Fleming also contributed in the fields of photometry, electronics, wireless telegraphy (radio), and electrical measurements. He was knighted in 1929, and he died at his home in Sidmouth, Devon in 1945. His contributions to electronic communications and radar were of vital importance in winning World War II. Fleming was awarded the IRE Medal of Honor in 1933 for "the conspicuous part he played in introducing physical and engineering principles into the radio art."

Books by Fleming

★ ''Electric Lamps and Electric Lighting'', 1899.

★ ''The Principles of Electric Wave Telegraphy'', 1906.

★ ''The Thermionic Valve and its Development in Radio Telegraphy and Telephony'', 1919.

References

★ James E. Brittain, "John A. Fleming", ''Proceedings of the IEEE'', 'Vol. 95', No. 1, 2007, pp. 313-315.

External articles

;Patents

★ Fleming Valve patent
;Websites

★ IEEE History Center biography

★ Department of Electronic & Electrical Engineering, UCL - home of the original Fleming valve