John Ambrose Fleming

British physicist and electrical engineer (1849–1945)

Fleming, who was born at Lancaster, studied for a short time at University College, London, but left before graduating. However, he continued his work for a science degree in his leisure hours while employed first in a shipwright's drawing office and later as a stockbroker's clerk. Between 1871 and 1880 he had alternate periods of school science teaching and further study, including working under James Clerk Maxwell from 1877 at the new Cavendish Laboratory in Cambridge. In 1881 he was appointed professor of mathematics and physics at University College, Nottingham. From 1882 to 1885 he worked as consultant to the Edison Electric Light Company in London. He was then appointed professor of electrical technology at University College, London, a post he held for 41 years.

At University College Fleming gave special courses and experimented on wireless telegraphy, cooperating a great deal with Guglielmo Marconi. One of Fleming's outstandingly important inventions was the thermionic vacuum tube, a rectifying device based on an effect discovered by Thomas Edison. Fleming's diode consisted of a glass bulb containing two electrodes. One, a metal filament, was heated to incandescence by an electric current, so that it emitted electrons by thermionic emission. The second electrode (the anode) could collect electrons if held at a positive potential with respect to the filament (the cathode) and a current would flow. Current could not flow in the opposite direction – hence the name ‘valve’ for such devices. Lee de Forest developed the device into the triode for amplifying current.

Other scientific contributions by Fleming included investigations into the property of materials, transformer design, electrical measurements, and photometry. He was an outstanding teacher and highly successful as a popular lecturer. Fleming's left hand rule and right hand rule are mnemonics for relating the direction of motion, magnetic field, and electric current in electric motors and generators respectively.

The work of British scientist John Ambrose Fleming (1849-1945) in inventing the thermionic valve or vacuum tube, arguably laid the basis for modern electronics. The so-called Fleming valve was the first electronic tube device, and was used to detect high-frequencywireless signals. Fleming also made other important contributions to the practical applications of electricity, further contributing to his field through his work as a noted educator and author.

Fleming was born on November 29, 1849, in Lancaster, England. He was the eldest of seven children born to James Fleming, a Congregational minister, and his wife, the daughter of John Bazley White, a trailblazer in Portland cement manufacturing. In 1854, Fleming's father took a post at the Kentish Town Congregational Chapel and moved the family to North London.

Showed Early Aptitude for Learning

Most of Fleming's initial education was at the University College School in London's West End. A solitary lad, he displayed an early aptness for the scientific and technical. He was very good at geometrical drawing, and by the age of 11 had organized his own workshop, in which he built model engines and ships. Although he performed poorly in Latin, Fleming stood out in mathematics sufficiently to be accepted to London's University College in 1867.

While studying for his undergraduate degree in physics and math, Fleming's financial circumstances made it necessary for him to take a job. He first tried working for a Dublin ship building company, but swiftly grew tired of tracing drawings. Soon, he left that position for a post as a clerk for a firm on the London Stock Exchange. Fleming held his clerk position for two years, studying in the evenings, before gaining his B.S. degree and ranking in the top two in his class in 1870.

Although financial concerns forced Fleming to periodically interrupt his education with the goal of earning money, he nonetheless persevered. After graduating from University College, he spent a year and a half accumulating funds as the science master at Rossall School before entering the Royal College of Chemistry, an institution that would later merge with the Royal School of Mines to form the Royal College of Science. There, he studied advanced chemistry with the distinguished chemist and co-discoverer of helium, Sir Edward Frankland (1825-1899). In 1874, Fleming's financial situation again demanded that he take a teaching position, so he signed on as a science master at Cheltenham College. That same year, he presented the very first scientific paper to the newly formed Physical Society of London. His subject was the contact theory of the galvanic cell.

During his studies, Fleming became intrigued by the work of eminent Scottish physicist James Clerk Maxwell (1831-1879), who was considered to be an expert in the behavior of electricity and magnetism. In 1877, Fleming enrolled at St. John's College, Cambridge, in order to study under Maxwell. He devoted himself to the program, eschewing most social contact, and finally received his Doctor of Science degree in 1880, a year after Maxwell's untimely death from cancer.

Educational Innovations and Early Consulting

After receiving his doctorate, Fleming was elected a fellow of St. John's and briefly taught math and physics at what is now Nottingham University. In 1881, he became a consultant for the Edison Telephone and Electric Light Companies in London. He served in that position, even traveling to the Edison Laboratories in the United States, for the next ten years. Fleming's tremendous practical knowledge was also employed by many British towns and cities then developing municipal lighting systems, as well as by such new electric companies as the Swan Lamp Factory and the London National Company. In these consulting capacities, Fleming contributed greatly to the development of electrical generator stations and distribution networks, and was the principal innovator behind the large-bulb incandescent lamp, which used an aged filament as its light source.

Concurrent to his consulting work, Fleming was also pioneering in the field of education. In 1885, he established England's first university department of electrical engineering at his alma mater, University College, London. As professor and chair of the department for the next four decades, he had the freedom to conduct his research while maintaining a lecture schedule. Fleming was also responsible for new teaching methods, such as incorporating experimentation and laboratory work into the classroom setting. Additionally, he devised the "right-hand rule," which provides students, even today, with a simple way to understand the directional relationships between the current, the magnetic field, and the and the resulting electromotive force. Fleming enjoyed teaching immensely, and was quite popular among his students, despite a tendency to lecture at breakneck speed that made taking notes a challenge. He and the students of UCL derived both pleasure and edification from a mutually beneficial relationship until Fleming's retirement in 1926.

Investigated Edison Effect

In 1899, Fleming was hired to be the scientific adviser to the Marconi Wireless Telegraph Company. The company was particularly interested in achieving greater distances in the transmission of wireless signals and Fleming became entranced by the puzzle as well. He helped design the Poldhu Power Station in Cornwall, England, the largest station in the country, and built much of the equipment that would help that facility make history. Poldu achieved fame in 1901, when it made the first successful transatlantic radio transmission. Although the groundbreaking transmission consisted of the Morse Code letter S - dot, dot, dot - Fleming inexplicably preferred the letter V - dot, dot, dot, dash - and conducted all his transmitter experiments using it. Indeed, he often became so absorbed in his work that he could be heard unconsciously humming or whistling the letter under his breath.

Fleming realized that the main impediment to further improvements in the development of radio signals was the inability to effectively detect the signals themselves, especially at higher frequencies. Crystal rectifiers could be used to convert alternating current into direct current in order to achieve amplification of weak radio waves, but were only efficient at lower frequencies. As he cast about for ideas about how to solve the problem, Fleming had an inspiration. He recalled an 1883 discovery by American scientist Thomas Alva Edison, one that Fleming had also investigated himself over the years, but that no one had found a particular use for. Known as the Edison Effect, the phenomenon was briefly explained by a contributor to the IEEE History Center Web site: "When he [Edison] introduced an extra electrode into the [incandescent] bulb, he realized that, even though the electrode wasn't part of the bulb's circuit, it could carry a current when it was of a positive potential relative to the filament. This so-called Edison Effect was later interpreted to be a flow of electrons from the hot filament to the extra electrode." Because electrons had been discovered in 1896 by Joseph J. Thompson (1856-1940), the Edison Effect showed more potential when Fleming took another look at it in 1904. He saw that a tube, or cylinder, could accomplish the work of crystal rectifiers more effectively.

Specifically, Fleming used a metal cylinder surrounding a filament, and a high vacuum. He then constructed a diode by attaching the cylinder plate and the filament through a second current circuit, using a battery to increase the electron flow and permitting the current to flow in only one direction. Able to detect high-frequency radio waves, this filament and plate apparatus was connected to an antenna circuit through which Fleming applied fluctuating voltages generated by radio signals. The changing voltages caused the plate current to vary in strength, creating changes that could be registered by a receiving apparatus. In essence, Fleming created a tube that controlled the flow of electricity in the same way that a fluid valve worked. He patented the device on November 16, 1904.

The Felming Valve

Fleming initially called his invention the oscillation valve, but it eventually became known by such alternate names as the Fleming valve, vacuum tube, and thermionic valve. While its immediate impact was felt, the invention proved much more important as a foundation for the field of electronics overall. One indication of its huge impact was the introduction of the Audion vacuum tube by American engineer Lee DeForest in 1906. DeForest took Fleming's idea and added a third electrode, which was called a grid because of the way in which it was constructed. The device caused a great uproar in the scientific community, as many saw it as an infringement on Fleming's invention. Fleming's own suit for patent infringement as to the Audion tube's thermionic technology failed. Nonetheless, his mark on the world was firmly in place.

The ramifications of the Fleming valve were myriad and far-reaching. It was a key component of radios for nearly three decades, until it was replaced by the transistor, and was integral to the development of television, telephones, and even early computers. Just as he had inaugurated the department of electrical engineering at University College, London, Fleming also established the basis for the field of electronics itself. As Orrin E. Dunlap, Jr., quoted Fleming as modestly commenting in Radio's One Hundred Men of Science, "The little things of today may develop into the great things of tomorrow."

A Full Retirement

Although Fleming's later years were marred by increasing deafness, he continued to delight in his many interests and hobbies. He was an early supporter of the nascent television industry, becoming president of the Television Society of London even after his retirement from University College, London in 1926. He kept current with his field, addressing the Physical Society of London for the last time in his late eighties. Fleming continued writing, too, adding Memories of a Scientific Life to his existing portfolio of 19 books. Mountain climbing, watercolor painting, and photography were among his other joys. A devout Christian, his preaching skills were such that he was once asked to deliver a sermon at the vaunted St. Martin's in the Fields in central London. Fleming was also irrepressible in more personal matters, as he ceased being a longtime widower - his first wife died in 1917 - at the age of 84 with his marriage to Olive Franks in 1933.

Fleming's awards and honors were, naturally, many. Among them were the highest distinction of the Royal Society of Arts, he was the receipient of the Gold Albert Medal in 1921, the Institution of Electrical Engineers' Faraday Medal in 1928, and the Institute of Radio Engineers' Gold Medal in 1933. He was knighted in 1929. Fleming died on April 18, 1945, at the age of 95, in Sidmouth, England.

Books

Dunlap, Orrin E., Jr., Radio's One Hundred Men of Science, 1944.

Notable Scientists: From 1900 to the Present, Gale Group, 2001.

World of Invention, 2nd edition, Gale Group, 1999.

Online

"Fleming's Revolutionary Invention Celebrated," University College, London, Web site,http://www.ucl.ac.uk/news/feature/newsitem.shtml?fleming (January 4, 2005).

"Fleming Valve, 1904," IEEE History Center Web site. http://www.ieee.org/organizations/history - center/fleming.html (January 4, 2005).

"John Ambrose Fleming," Radio-Electronics.com,http://www.radio-electronics.com/info/radio - history/gtnames/fleming.php (January 3, 2005).

For other persons named John Fleming, see John Fleming (disambiguation).

Sir J. Ambrose Fleming
Born	John Ambrose Fleming 29 November 1849(1849-11-29) Lancaster, Lancashire, England
Died	18 April 1945 (aged 95) Sidmouth, Devon, England
Residence	England
Nationality	English
Fields	Electrical engineer and physicist
Institutions	University College, London University of Nottingham Cambridge University Edison Electric Light Co. Victoria Institute
Alma mater	University College, London Royal College of Science
Doctoral advisor	Frederick Guthrie
Doctoral students	Harold Barlow
Other notable students	Balthasar van der Pol
Known for	Fleming's left hand rule Fleming's right hand rule Kenotron
Notable awards	Hughes Medal (1910) Albert Medal (1921) Faraday Medal (1928) Duddell Medal (1930) IRE Medal of Honor (1933)
Religious stance	Congregationalist

Sir John Ambrose Fleming (29 November 1849 – 18 April 1945) was an English electrical engineer and physicist. He is known for inventing the first thermionic valve or vacuum tube, the diode, then called the kenotron in 1904.^[1] He also invented the right-hand rule, used in mathematics and electronics.^[2] He was born the eldest of seven children of James Fleming DD (died 1879), a Congregational minister, and his wife, Mary Ann, at Lancaster, Lancashire and baptized on 11 February 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 1 Early years 2 Education and marriages 3 Activities and achievements 4 Books by Fleming 5 References 6 External articles

Early years

Ambrose Fleming was born in Lancaster and educated at University College School, London, and University College London. He entered St John's College, Cambridge in 1877, gaining his B.A. in 1881 and becoming a Fellow of St John's in 1883.^[3] He went on to Lecture at several universities including the University of Cambridge, the University of Nottingham, and University College London, where he was the first professor of Electrical Engineering. He was also consultant to the Marconi Wireless Telegraph Company, Swan Company, 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 paid employment.

He enrolled for a BSc degree at University College, London, graduated in 1870, and studied under the mathematician Augustus de Morgan and the physicist George 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 Alessandro Volta's 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 a living and in the summer of 1874 he became science master at Cheltenham College, a public school, earning £400 per year. (He later also taught at Rossall School.) 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 at the age of 27, he once again enrolled as a student, this time at Cambridge. 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 Class Honours degree 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 he left after less than a year.

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

After leaving the University of Nottingham in 1882, Fleming took up the post of "Electrician" to the Edison Electrical Light Company, advising on lighting systems and the new Ferranti alternating current systems. In 1884 Fleming joined University College London taking up the Chair of Electrical Technology, the first of its kind in England. 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 Laboratory was founding at University College, London and Fleming took up the Pender Chair after the £5000 was endowed as a memorial to John Pender, the founder of Cable and Wireless.^[4]. In 1899 Fleming became Scientific Advisor to the Marconi Company and soon after began work on the designing the power plant to enable the Marconi Company to transmit across the Atlantic.

In November 1904, he invented the two-electrode vacuum-tube rectifier, which he called the oscillation valve. He would later patent this invention.^[5] It was also called a thermionic valve, vacuum diode, kenotron, thermionic tube, or 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.^[6] 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 it was superseded by solid state electronic technology more than 50 years later.

Fleming retired from University College, London in 1927 at the age of 77. He remained active, becoming a committed advocate of the new technology of Television which included servicing as the first president of the Television Society.

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 the first electronic amplifier, a 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). The court battle over these patents lasted for nearly many years with victories at different stages for both sides. Fleming also contributed in the fields of photometry, electronics, wireless telegraphy (radio), and electrical measurements. He coined the term Power Factor to describe the true power flowing an AC power system. He was knighted in 1929, and 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".

Note from eulogy at the Centenary celebration of the invention of the thermionic valve:

One century ago, in November 1904, John Ambrose Fleming FRS, Pender Professor at UCL, filed GB patent 190424850 in Great Britain, for a device called the Thermionic Valve. When inserted together with a galvanometer, into a tuned electrical circuit, it could be used as a very sensitive rectifying detector of high frequency wireless currents, known as radio waves. It was a major step forward in the ‘wireless revolution’.

In November 1905, he patented the "Fleming Valve" (US patent 803684 ). As a rectifying diode, and forerunner to the triode valve and many related structures, it can also be considered to be the device that gave birth to modern electronics.

In the ensuing years such valves, were largely superseded by "cat’s whiskers", and decades later most electron tubes, as they became generically known, were gradually replaced by semiconductor diodes and transistors, which were significantly smaller, cheaper, and more reliable. In time and in turn, even these have been largely replaced by integrated circuits, better known as silicon chips.

Today, descendants of the original vacuum tube still play an important role in a range of applications. They can be found in the power stages of radio and television transmitters, in audio amplifiers, as detectors of optical and short wavelength radiation, and in sensitive equipment that must be "radiation-hard".

On the 27th November 2004 a Blue Plaque (presented by the Institute of Physics) was unveiled at the "Norman Lockyer Observatory", Sidmouth, to mark 100 years since the invention of the Thermionic Radio Valve.

Books by Fleming

• Electric Lamps and Electric Lighting: A course of four lectures on electric illumination delivered at the Royal Institution of Great Britain (1894) 228 pages, ISBN 0548479377.
• The Alternate Current Transformer in Theory and Practice "The Electrician" Printing and Publishing Company (1896)
• Magnets and Electric Currents E. & F. N. Spon. (1898)
• A Handbook for the Electrical Laboratory and Testing Room "The Electrician" Printing and Publishing Company (1901)
• Waves and Ripples in Water, Air, and Aether MacMillan (1902).
• The Evidence of Things Not Seen Christian Knowledge Society: London (1904)
• The Principles of Electric Wave Telegraphy (1906), Longmans Green, London, 671 pages.
• The Propagation of Electric Currents in Telephone and Telegraph Conductors (1908) Constable, 316 pages.
• An Elementary Manual of Radiotelegraphy and Radiotelephony (1911) Longmans Green, London, 340 pages.
• On the power factor and conductivity of dielectrics when tested with alternating electric currents of telephonic frequency at various temperatures (1912) Gresham, 82 pages, ASIN: B0008CJBIC
• The Wonders of Wireless Telegraphy : Explained in simple terms for the non-technical reader Society for promoting Christian Knowledge (1913)
• The Wireless Telegraphist's Pocket Book of Notes, Formulae and Calculations The Wireless Press (1915)
• The Thermionic Valve and its Development in Radio Telegraphy and Telephony (1919).
• Fifty Years of Electricity The Wireless Press (1921)
• Electrons, Electric Waves and Wireless telephony The Wireless Press (1923)
• Introduction to Wireless Telegraphy and Telephony Sir Isaac Pitman and Sons Ltd. (1924)
• Mercury-arc Rectifiers and Mercury-vapour Lamps London. Pitman (1925)
• The Electrical Educator (3 volumes), The New Era Publishing Co Ltd (1927)
• Memories of a Scientific life Marshall, Morgan & Scott (1934)
• Evolution or Creation? (1938) Marshall Morgan and Scott, 114 pages, ASIN: B00089BL7Y - outlines objections to Darwin.
• Mathematics for Engineers George Newnes Ltd (1938)

References

1. ^ Harr, Chris (2003-06-23). "Ambrose J. Fleming biography". Pioneers of Computing. The History of Computing Project. http://www.thocp.net/biographies/fleming_ambrose.htm. Retrieved 2008-04-30. 
2. ^ "Right and left hand rules". Tutorials, Magnet Lab U.. National High Magnetic Field Laboratory. http://www.magnet.fsu.edu/education/tutorials/java/handrules/index.html. Retrieved 2008-04-30. 
3. ^ Fleming, John Ambrose in Venn, J. & J. A., Alumni Cantabrigienses, Cambridge University Press, 10 vols, 1922–1958.
4. ^ "IN SIR JOHN PENDER'S MEMORY.; Bust to be Erected and a Laboratory in London Endowed, New Your Times, June 27th, 1897"
5. ^ Fleming Valve patent U.S. Patent 803,684
6. ^ "Misreading the Supreme Court: A Puzzling Chapter in the History of Radio". November 1998, Mercurians.org.

• Brittain James E. (2007). "John A. Fleming". Proceedings of the IEEE 95 (1): 313–315. 
• Mitchell, John; Griffiths, Hugh; Boyd, Ian (2006). Sarkar, Tapan; Mailloux, Robert; Oliner, Arthur et al.. eds. History of Wireless. New Jersey: John Wiley & Sons. pp. 311-326}. ISBN 0-471-71814-9. 

External articles

• IEEE History Center biography
• Department of Electronic & Electrical Engineering, UCL - home of the original Fleming valve
• 100 Years of Electronics 2004 - The Centenary of the Fleming Valve

v • d • e IEEE Medal of Honor 1926–1950 Greenleaf W. Pickard (1926) · Louis W. Austin (1927) · Jonathan Zenneck (1928) · George W. Pierce (1929) · Peder Oluf Pedersen (1930) · Gustave-Auguste Ferrié (1931) · Arthur Edwin Kennelly (1932) · John Ambrose Fleming (1933) · Stanford C. Hooper (1934) · Balthasar van der Pol (1935) · George Ashley Campbell (1936) · Melville Eastham (1937) · John H. Dellinger (1938) · Albert G. Lee (1939) · Lloyd Espenschied (1940) · Alfred Norton Goldsmith (1941) · Albert H. Taylor (1942) · William Wilson (1943) · Haraden Pratt (1944) · Harold Beverage (1945) · Ralph Hartley (1946) · Lawrence C. F. Horle (1948) · Ralph Bown (1949) · Frederick Terman (1950) Complete roster: 1917–1925 · 1926–1950 · 1951–1975 · 1976–2000 · 2001–present

Persondata
NAME	Fleming, Sir J. Ambrose
ALTERNATIVE NAMES
SHORT DESCRIPTION	Electrical engineer and physicist
DATE OF BIRTH	November 29, 1849(1849-11-29)
PLACE OF BIRTH	Lancaster, Lancashire, England
DATE OF DEATH	April 18, 1945
PLACE OF DEATH	Sidmouth, Devon, England

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