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1 ламповый передатчик
Русско-английский научно-технический словарь Масловского > ламповый передатчик
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2 ламповый передатчик
1) Engineering: tube transmitter2) Electronics: thermionic transmitter, vacuum-tube transmitter, valve transmitter3) Household appliances: thermionic valve transmitterУниверсальный русско-английский словарь > ламповый передатчик
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3 ламповый передатчик
1) thermionic valve transmitter
2) tube transmitter -
4 Appleton, Sir Edward Victor
[br]b. 6 September 1892 Bradford, Englandd. 21 April 1965 Edinburgh, Scotland[br]English physicist awarded the Nobel Prize for Physics for his discovery of the ionospheric layer, named after him, which is an efficient reflector of short radio waves, thereby making possible long-distance radio communication.[br]After early ambitions to become a professional cricketer, Appleton went to St John's College, Cambridge, where he studied under J.J.Thompson and Ernest Rutherford. His academic career interrupted by the First World War, he served as a captain in the Royal Engineers, carrying out investigations into the propagation and fading of radio signals. After the war he joined the Cavendish Laboratory, Cambridge, as a demonstrator in 1920, and in 1924 he moved to King's College, London, as Wheatstone Professor of Physics.In the following decade he contributed to developments in valve oscillators (in particular, the "squegging" oscillator, which formed the basis of the first hard-valve time-base) and gained international recognition for research into electromagnetic-wave propagation. His most important contribution was to confirm the existence of a conducting ionospheric layer in the upper atmosphere capable of reflecting radio waves, which had been predicted almost simultaneously by Heaviside and Kennelly in 1902. This he did by persuading the BBC in 1924 to vary the frequency of their Bournemouth transmitter, and he then measured the signal received at Cambridge. By comparing the direct and reflected rays and the daily variation he was able to deduce that the Kennelly- Heaviside (the so-called E-layer) was at a height of about 60 miles (97 km) above the earth and that there was a further layer (the Appleton or F-layer) at about 150 miles (240 km), the latter being an efficient reflector of the shorter radio waves that penetrated the lower layers. During the period 1927–32 and aided by Hartree, he established a magneto-ionic theory to explain the existence of the ionosphere. He was instrumental in obtaining agreement for international co-operation for ionospheric and other measurements in the form of the Second Polar Year (1932–3) and, much later, the International Geophysical Year (1957–8). For all this work, which made it possible to forecast the optimum frequencies for long-distance short-wave communication as a function of the location of transmitter and receiver and of the time of day and year, in 1947 he was awarded the Nobel Prize for Physics.He returned to Cambridge as Jacksonian Professor of Natural Philosophy in 1939, and with M.F. Barnett he investigated the possible use of radio waves for radio-location of aircraft. In 1939 he became Secretary of the Government Department of Scientific and Industrial Research, a post he held for ten years. During the Second World War he contributed to the development of both radar and the atomic bomb, and subsequently served on government committees concerned with the use of atomic energy (which led to the establishment of Harwell) and with scientific staff.[br]Principal Honours and DistinctionsKnighted (KCB 1941, GBE 1946). Nobel Prize for Physics 1947. FRS 1927. Vice- President, American Institute of Electrical Engineers 1932. Royal Society Hughes Medal 1933. Institute of Electrical Engineers Faraday Medal 1946. Vice-Chancellor, Edinburgh University 1947. Institution of Civil Engineers Ewing Medal 1949. Royal Medallist 1950. Institute of Electrical and Electronics Engineers Medal of Honour 1962. President, British Association 1953. President, Radio Industry Council 1955–7. Légion d'honneur. LLD University of St Andrews 1947.Bibliography1925, joint paper with Barnett, Nature 115:333 (reports Appleton's studies of the ionosphere).1928, "Some notes of wireless methods of investigating the electrical structure of the upper atmosphere", Proceedings of the Physical Society 41(Part III):43. 1932, Thermionic Vacuum Tubes and Their Applications (his work on valves).1947, "The investigation and forecasting of ionospheric conditions", Journal of theInstitution of Electrical Engineers 94, Part IIIA: 186 (a review of British work on the exploration of the ionosphere).with J.F.Herd \& R.A.Watson-Watt, British patent no. 235,254 (squegging oscillator).Further ReadingWho Was Who, 1961–70 1972, VI, London: A. \& C.Black (for fuller details of honours). R.Clark, 1971, Sir Edward Appleton, Pergamon (biography).J.Jewkes, D.Sawers \& R.Stillerman, 1958, The Sources of Invention.KFBiographical history of technology > Appleton, Sir Edward Victor
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5 De Forest, Lee
SUBJECT AREA: Broadcasting, Electronics and information technology, Photography, film and optics, Recording, Telecommunications[br]b. 26 August 1873 Council Bluffs, Iowa, USAd. 30 June 1961 Hollywood, California, USA[br]American electrical engineer and inventor principally known for his invention of the Audion, or triode, vacuum tube; also a pioneer of sound in the cinema.[br]De Forest was born into the family of a Congregational minister that moved to Alabama in 1879 when the father became President of a college for African-Americans; this was a position that led to the family's social ostracism by the white community. By the time he was 13 years old, De Forest was already a keen mechanical inventor, and in 1893, rejecting his father's plan for him to become a clergyman, he entered the Sheffield Scientific School of Yale University. Following his first degree, he went on to study the propagation of electromagnetic waves, gaining a PhD in physics in 1899 for his thesis on the "Reflection of Hertzian Waves from the Ends of Parallel Wires", probably the first US thesis in the field of radio.He then joined the Western Electric Company in Chicago where he helped develop the infant technology of wireless, working his way up from a modest post in the production area to a position in the experimental laboratory. There, working alone after normal working hours, he developed a detector of electromagnetic waves based on an electrolytic device similar to that already invented by Fleming in England. Recognizing his talents, a number of financial backers enabled him to set up his own business in 1902 under the name of De Forest Wireless Telegraphy Company; he was soon demonstrating wireless telegraphy to interested parties and entering into competition with the American Marconi Company.Despite the failure of this company because of fraud by his partners, he continued his experiments; in 1907, by adding a third electrode, a wire mesh, between the anode and cathode of the thermionic diode invented by Fleming in 1904, he was able to produce the amplifying device now known as the triode valve and achieve a sensitivity of radio-signal reception much greater than possible with the passive carborundum and electrolytic detectors hitherto available. Patented under the name Audion, this new vacuum device was soon successfully used for experimental broadcasts of music and speech in New York and Paris. The invention of the Audion has been described as the beginning of the electronic era. Although much development work was required before its full potential was realized, the Audion opened the way to progress in all areas of sound transmission, recording and reproduction. The patent was challenged by Fleming and it was not until 1943 that De Forest's claim was finally recognized.Overcoming the near failure of his new company, the De Forest Radio Telephone Company, as well as unsuccessful charges of fraudulent promotion of the Audion, he continued to exploit the potential of his invention. By 1912 he had used transformer-coupling of several Audion stages to achieve high gain at radio frequencies, making long-distance communication a practical proposition, and had applied positive feedback from the Audion output anode to its input grid to realize a stable transmitter oscillator and modulator. These successes led to prolonged patent litigation with Edwin Armstrong and others, and he eventually sold the manufacturing rights, in retrospect often for a pittance.During the early 1920s De Forest began a fruitful association with T.W.Case, who for around ten years had been working to perfect a moving-picture sound system. De Forest claimed to have had an interest in sound films as early as 1900, and Case now began to supply him with photoelectric cells and primitive sound cameras. He eventually devised a variable-density sound-on-film system utilizing a glow-discharge modulator, the Photion. By 1926 De Forest's Phonofilm had been successfully demonstrated in over fifty theatres and this system became the basis of Movietone. Though his ideas were on the right lines, the technology was insufficiently developed and it was left to others to produce a system acceptable to the film industry. However, De Forest had played a key role in transforming the nature of the film industry; within a space of five years the production of silent films had all but ceased.In the following decade De Forest applied the Audion to the development of medical diathermy. Finally, after spending most of his working life as an independent inventor and entrepreneur, he worked for a time during the Second World War at the Bell Telephone Laboratories on military applications of electronics.[br]Principal Honours and DistinctionsInstitute of Electronic and Radio Engineers Medal of Honour 1922. President, Institute of Electronic and Radio Engineers 1930. Institute of Electrical and Electronics Engineers Edison Medal 1946.Bibliography1904, "Electrolytic detectors", Electrician 54:94 (describes the electrolytic detector). 1907, US patent no. 841,387 (the Audion).1950, Father of Radio, Chicago: WIlcox \& Follett (autobiography).De Forest gave his own account of the development of his sound-on-film system in a series of articles: 1923. "The Phonofilm", Transactions of the Society of Motion Picture Engineers 16 (May): 61–75; 1924. "Phonofilm progress", Transactions of the Society of Motion Picture Engineers 20:17–19; 1927, "Recent developments in the Phonofilm", Transactions of the Society of Motion Picture Engineers 27:64–76; 1941, "Pioneering in talking pictures", Journal of the Society of Motion Picture Engineers 36 (January): 41–9.Further ReadingG.Carneal, 1930, A Conqueror of Space (biography).I.Levine, 1964, Electronics Pioneer, Lee De Forest (biography).E.I.Sponable, 1947, "Historical development of sound films", Journal of the Society of Motion Picture Engineers 48 (April): 275–303 (an authoritative account of De Forest's sound-film work, by Case's assistant).W.R.McLaurin, 1949, Invention and Innovation in the Radio Industry.C.F.Booth, 1955, "Fleming and De Forest. An appreciation", in Thermionic Valves 1904– 1954, IEE.V.J.Phillips, 1980, Early Radio Detectors, London: Peter Peregrinus.KF / JW
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