Sir John Ambrose Fleming
John Ambrose Fleming
29 November 1849
|Died||18 April 1945 95) (aged|
|Alma mater|| University College London |
Royal College of Science
|Known for|| Fleming's left hand rule |
Vacuum tube (Fleming valve)
|Awards|| Hughes Medal (1910)|
Albert Medal (1921)
Faraday Medal (1928)
Duddell Medal (1930)
IRE Medal of Honor (1933)
Franklin Medal (1935)
Fellow of the Royal Society
|Fields||Electrical engineer and physicist|
|Institutions|| University College London |
University of Nottingham
Edison Electric Light Co.
|Doctoral advisor||Frederick Guthrie|
|Doctoral students||Harold Barlow|
|Other notable students||Balthasar van der Pol|
Sir John Ambrose Fleming FRS(29 November 1849 – 18 April 1945), an English electrical engineer and physicist, invented the first thermionic valve or vacuum tube, designed the radio transmitter with which the first transatlantic radio transmission was made, and also established the right-hand rule used in physics. He was the eldest of seven children of James Fleming DD (died 1879), a Congregational minister, and his wife Mary Ann, at Lancaster, Lancashire, and baptised on 11 February 1850. A devout Christian, he once preached at St Martin-in-the-Fields in London on evidence for the resurrection. In 1932, he and Douglas Dewar and Bernard Acworth helped establish the Evolution Protest Movement. Childless himself, he bequeathed much of his estate to Christian charities, especially those for the poor. He was a noted photographer, painted water colours, and enjoyed climbing the Alps.
Fellowship of the Royal Society is an award granted to individuals that the Royal Society of London judges to have made a 'substantial contribution to the improvement of natural knowledge, including mathematics, engineering science and medical science'.
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of phenomena, and usually frame their understanding in mathematical terms. Physicists work across a wide range of research fields, spanning all length scales: from sub-atomic and particle physics, through biological physics, to cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: experimental physicists who specialize in the observation of physical phenomena and the analysis of experiments, and theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their knowledge towards solving practical problems or to developing new technologies.
In electronics, a vacuum tube, an electron tube, or valve or, colloquially, a tube, is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied.
Ambrose Fleming was born in Lancaster and educated at Lancaster Royal Grammar School, University College School, London, and then University College London. He entered St John's College, Cambridge in 1877, gaining his BA in 1881 and becoming a Fellow of St John's in 1883.He went on to lecture at several universities including the University of Cambridge, University College 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.
Lancaster Royal Grammar School (LRGS) is a selective grammar school for boys aged 11–18 in Lancaster, Lancashire, England. It also has academy status. Old students belong to The Old Lancastrians. It is one of England's 36 state boarding schools. The school will have a sixth form for girls from September 2019.
University College School, generally known as UCS Hampstead, is an independent day school in Frognal, northwest London, England. The school was founded in 1830 by University College London and inherited many of that institution's progressive and secular views.
UCL is a public research university located in London, United Kingdom. It is a constituent college of the federal University of London, and is the third largest university in the United Kingdom by total enrolment, and the largest by postgraduate enrolment.
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.
Geometry is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space. A mathematician who works in the field of geometry is called a geometer.
Latin is a classical language belonging to the Italic branch of the Indo-European languages. The Latin alphabet is derived from the Etruscan and Greek alphabets and ultimately from the Phoenician alphabet.
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.
Fleming 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. He was among the two or perhaps three University students who attended Maxwell's last Course. 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 University College Nottingham, but he left after less than a year.
George Carey Foster FRS was a chemist and physicist, born at Sabden in Lancashire. He was Professor of Physics at University College London, and served as the first Principal from 1900 to 1904.
The Royal College of Science was a higher education institution located in South Kensington; it was a constituent college of Imperial College London from 1907 until it was wholly absorbed by Imperial in 2002. Alumni include H. G. Wells and Brian May and are distinguishable by the letters ARCS(Associate of the Royal College of Science) after their name. Organisations linked with the college include the Royal College of Science Union and the Royal College of Science Association.
South Kensington is an affluent district of West London in the Royal Borough of Kensington and Chelsea. With some of its easterly areas shared with the City of Westminster, the district is known as a popular tourist destination due to its density of museums and culutral landmarks.
On 11 June 1887 he marriedClara 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.
Bristol is a city and county in South West England with a population of 459,300. The wider district has the 10th-largest population in England. The urban area population of 724,000 is the 8th-largest in the UK. The city borders North Somerset and South Gloucestershire, with the cities of Bath and Gloucester to the south-east and north-east, respectively. South Wales lies across the Severn estuary.
Cardiff is the capital of Wales, and its largest city. The eleventh-largest city in the United Kingdom, it is Wales's chief commercial centre, the base for most national cultural institutions and Welsh media, and the seat of the National Assembly for Wales. At the 2011 census, the unitary authority area population was estimated to be 346,090, and the wider urban area 479,000. Cardiff is a significant tourist centre and the most popular visitor destination in Wales with 21.3 million visitors in 2017. In 2011, Cardiff was ranked sixth in the world in National Geographic's alternative tourist destinations.
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.
The University of Nottingham is a public research university in Nottingham, United Kingdom. It was founded as University College Nottingham in 1881, and was granted a royal charter in 1948.
Ferranti or Ferranti International plc was a UK electrical engineering and equipment firm that operated for over a century from 1885 until it went bankrupt in 1993. The company was once a constituent of the FTSE 100 Index.
The Pender Chair is the post that is generally held by the head of the Department of Electronic and Electrical Engineering of University College London.
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 Marconi had used up to then. He contracted Fleming, an expert in power engineering, to design the radio transmitter. Fleming 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 in Cornwall, UK, 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 Co. had made Fleming 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 Fleming 500 shares of Marconi stock if the project was successful. Fleming was bitter about his treatment. He honoured his agreement and didn't speak about it throughout Marconi's life, but after his death in 1937 said Marconi had been "very ungenerous".
In 1904, working for the Marconi company to improve transatlantic radio reception, Fleming invented the two-electrode vacuum tube 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 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.
In 1906, Lee De Forest of the US 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 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 electro-mechanical 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. 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 in an AC power system.
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 serving as the second president of the Television Society. 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". A note from eulogy at the Centenary celebration of the invention of the thermionic valve:
In November 1905, he patented the "Fleming Valve" ( US 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, valves quickly superseded "cat's whiskers" and were the main device used to create the electronics industry of today. They remained dominant until the transistor took dominance in the early 1970s.
Today, descendants of the original valve (or 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 musical instrument amplifiers (particularly electric guitar and bass amplifiers), in some high-end audio amplifiers, as detectors of optical and short wavelength radiation, and in sensitive equipment that must be "radiation-hard".
In 1941 the London Power Company commemorated Fleming by naming a new 1,555 GRT coastal collier SS Ambrose Fleming.
On 27 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.
In 1894 and 1917 Ambrose Fleming was invited to deliver the Royal Institution Christmas Lecture on The Work of an Electric Current and Our Useful Servants : Magnetism and Electricity respectively.
An electronic oscillator is an electronic circuit that produces a periodic, oscillating electronic signal, often a sine wave or a square wave. Oscillators convert direct current (DC) from a power supply to an alternating current (AC) signal. They are widely used in many electronic devices. Common examples of signals generated by oscillators include signals broadcast by radio and television transmitters, clock signals that regulate computers and quartz clocks, and the sounds produced by electronic beepers and video games.
Guglielmo Marconi, 1st Marquis of Marconi was an Italian inventor and electrical engineer, known for his pioneering work on long-distance radio transmission, development of Marconi's law, and a radio telegraph system. He is credited as the inventor of radio, and he shared the 1909 Nobel Prize in Physics with Karl Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy".
The early history of radio is the history of technology that produces and uses radio instruments that use radio waves. Within the timeline of radio, many people contributed theory and inventions in what became radio. Radio development began as "wireless telegraphy". Later radio history increasingly involves matters of broadcasting.
A triode is an electronic amplifying vacuum tube consisting of three electrodes inside an evacuated glass envelope: a heated filament or cathode, a grid, and a plate (anode). Developed from Lee De Forest's 1906 Audion, a partial vacuum tube that added a grid electrode to the thermionic diode, the triode was the first practical electronic amplifier and the ancestor of other types of vacuum tubes such as the tetrode and pentode. Its invention founded the electronics age, making possible amplified radio technology and long-distance telephony. Triodes were widely used in consumer electronics devices such as radios and televisions until the 1970s, when transistors replaced them. Today, their main remaining use is in high-power RF amplifiers in radio transmitters and industrial RF heating devices. In recent years there has been a resurgence in demand for low power triodes due to renewed interest in tube-type audio systems by audiophiles who prefer the sound of tube-based electronics.
Wireless telegraphy means transmission of telegraph signals by radio waves; a more specific term for this is radiotelegraphy. Before about 1910 when radio became dominant, the term wireless telegraphy was also used for various other experimental technologies for transmitting telegraph signals without wires, such as electromagnetic induction, and ground conduction telegraph systems.
Reginald Aubrey Fessenden was a Canadian-born inventor, who did a majority of his work in the United States and also claimed U.S. citizenship through his American-born father. During his life he received hundreds of patents in various fields, most notably ones related to radio and sonar.
Thermionic emission is the thermally induced flow of charge carriers from a surface or over a potential-energy barrier. This occurs because the thermal energy given to the carrier overcomes the work function of the material. The charge carriers can be electrons or ions, and in older literature are sometimes referred to as thermions. After emission, a charge that is equal in magnitude and opposite in sign to the total charge emitted is initially left behind in the emitting region. But if the emitter is connected to a battery, the charge left behind is neutralized by charge supplied by the battery as the emitted charge carriers move away from the emitter, and finally the emitter will be in the same state as it was before emission.
Lee de Forest was an American inventor, self-described "Father of Radio", and a pioneer in the development of sound-on-film recording used for motion pictures. He had over 180 patents, but also a tumultuous career—he boasted that he made, then lost, four fortunes. He was also involved in several major patent lawsuits, spent a substantial part of his income on legal bills, and was even tried for mail fraud. His most famous invention, in 1906, was the three-element "Audion" (triode) vacuum tube, the first practical amplification device. Although De Forest had only a limited understanding of how it worked, it was the foundation of the field of electronics, making possible radio broadcasting, long distance telephone lines, and talking motion pictures, among countless other applications.
The Audion was an electronic detecting or amplifying vacuum tube invented by American electrical engineer Lee de Forest in 1906. It was the first triode, consisting of an evacuated glass tube containing three electrodes: a heated filament, a grid, and a plate. It is important in the history of technology because it was the first widely used electronic device which could amplify; a small electrical signal applied to the grid could control a larger current flowing from the filament to plate.
Greenleaf Whittier Pickard was a United States radio pioneer. Pickard was a researcher in the early days of wireless. While not the earliest discoverer of the rectifying properties of contact between certain solid materials, he was largely responsible and most famous for the development of the crystal detector, the earliest type of diode detector. The crystal detector was the central component in many early radio receivers from around 1906 until about 1920. Pickard also experimented with antennas, radio wave propagation and noise suppression. On August 30, 1906 he filed a patent for a silicon crystal detector, which was granted on November 20, 1906. On June 10, 1907 he filed a patent for a Magnetic Aerial which was granted on January 21, 1908. Pickard's loop antenna had directional properties that could be used to reduce interference to the intended wireless communications. On June 21, 1911 he filed a patent on a crystal detector incorporating a springy low inertia wire of about 24 gauge formed with a loop or helix and pointed to make contact with the crystal. Crystal detectors incorporating this construction would become the most widely used and popularly known by the term cat whisker detector. This patent was granted on July 21, 1914. Greenleaf Whittier Pickard was named after his great-uncle, the American Quaker John Greenleaf Whittier (1807-1892). Pickard was president of the Institute of Radio Engineers in 1913.
A spark-gap transmitter is an obsolete type of radio transmitter which generates radio waves by means of an electric spark. Spark-gap transmitters were the first type of radio transmitter, and were the main type used during the wireless telegraphy or "spark" era, the first three decades of radio, from 1887 to the end of World War 1. German physicist Heinrich Hertz built the first experimental spark-gap transmitters in 1887, with which he discovered radio waves and studied their properties.
A plate, usually called anode in Britain, is a type of electrode that forms part of a vacuum tube. It is usually made of sheet metal, connected to a wire which passes through the glass envelope of the tube to a terminal in the base of the tube, where it is connected to the external circuit. The plate is given a positive potential, and its function is to attract and capture the electrons emitted by the cathode. Although it is sometimes a flat plate, it is more often in the shape of a cylinder or flat open-ended box surrounding the other electrodes.
A crystal detector is an obsolete electronic component in some early 20th century radio receivers that used a piece of crystalline mineral as a detector (demodulator) to rectify the alternating current radio signal to extract the audio modulation which produced the sound in the earphones. It was the first type of semiconductor diode, and one of the first semiconductor electronic devices. The most common type was the so-called cat whisker detector, which consisted of a piece of crystalline mineral, usually galena, with a fine wire touching its surface. The "asymmetric conduction" of electric current across electrical contacts between a crystal and a metal was discovered in 1874 by Karl Ferdinand Braun. Crystals were first used as radio wave detectors in 1894 by Jagadish Chandra Bose in his microwave experiments. who first patented a crystal detector in 1901. The crystal detector was developed into a practical radio component mainly by G. W. Pickard, who began research on detector materials in 1902 and found hundreds of substances that could be used in forming rectifying junctions. The physical principles by which they worked were not understood at the time they were used, but subsequent research into these primitive point contact semiconductor junctions in the 1930s and 1940s led to the development of modern semiconductor electronics.
The invention of radio communication, although generally attributed to Guglielmo Marconi in the 1890s, spanned many decades, from theoretical underpinnings, through proof of the phenomenon's existence, development of technical means, to its final use in signalling.
The timeline of radio lists within the history of radio, the technology and events that produced instruments that use radio waves and activities that people undertook. Later, the history is dominated by programming and contents, which is closer to general history.
The Fleming valve, also called the Fleming oscillation valve, was a thermionic valve or vacuum tube invented in 1904 by Englishman John Ambrose Fleming as a detector for early radio receivers used in electromagnetic wireless telegraphy. It was the first practical vacuum tube and the first thermionic diode, a vacuum tube whose purpose is to conduct current in one direction and block current flowing in the opposite direction. The thermionic diode was later widely used as a rectifier — a device which converts alternating current (AC) into direct current (DC) — in the power supplies of a wide range of electronic devices, until beginning to be replaced by the selenium rectifier in the early 1930s and almost completely replaced by the semiconductor diode in the 1960s. The Fleming valve was the forerunner of all vacuum tubes, which dominated electronics for 50 years. The IEEE has described it as "one of the most important developments in the history of electronics", and it is on the List of IEEE Milestones for electrical engineering.
Marconi's law is the relation between length of antennas and maximum signaling distance of radio transmissions. Guglielmo Marconi enunciated at one time an empirical law that, for simple vertical sending and receiving antennas of equal height, the maximum working telegraphic distance varied as the square of the height of the antenna. It has been stated that the rule was tested in experiments made on Salisbury Plain in 1897, and also by experiments made by Italian naval officers on behalf of the Royal Italian Navy in 1900 and 1901. Captain Quintino Bonomo gave a report of these experiments in an official report.
Captain Henry Joseph Round was an English engineer and one of the early pioneers of radio. He was the first to report observation of electroluminescence from a solid state diode, leading to the discovery of the light-emitting diode. He was a personal assistant to Guglielmo Marconi.
The history of electronic engineering is a long one. Chambers Twentieth Century Dictionary (1972) defines electronics as "The science and technology of the conduction of electricity in a vacuum, a gas, or a semiconductor, and devices based thereon".
The electronics age may be said to have been ushered in with the invention of the vacuum diode valve in 1902 by the Briton John Fleming (himself coining the word "electronics"), the immediate application being in the field of radio.
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John Ambrose Fleming