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1 Braun, Karl Ferdinand
[br]b. 6 June 1850 Fulda, Hesse, Germanyd. 20 April 1918 New York City, New York, USA[br]German physicist who shared with Marconi the 1909 Nobel Prize for Physics for developments in wireless telegraphy; inventor of the cathode ray oscilloscope.[br]After obtaining degrees from the universities of Marburg and Berlin (PhD) and spending a short time as Headmaster of the Thomas School in Berlin, Braun successively held professorships in theoretical physics at the universities of Marburg (1876), Strasbourg (1880) and Karlsruhe (1883) before becoming Professor of Experimental Physics at Tübingen in 1885 and Director and Professor of Physics at Strasbourg in 1895.During this time he devised experimental apparatus to determine the dielectric constant of rock salt and developed the Braun high-tension electrometer. He also discovered that certain mineral sulphide crystals would only conduct electricity in one direction, a rectification effect that made it possible to detect and demodulate radio signals in a more reliable manner than was possible with the coherer. Primarily, however, he was concerned with improving Marconi's radio transmitter to increase its broadcasting range. By using a transmitter circuit comprising a capacitor and a spark-gap, coupled to an aerial without a spark-gap, he was able to obtain much greater oscillatory currents in the latter, and by tuning the transmitter so that the oscillations occupied only a narrow frequency band he reduced the interference with other transmitters. Other achievements include the development of a directional aerial and the first practical wavemeter, and the measurement in Strasbourg of the strength of radio waves received from the Eiffel Tower transmitter in Paris. For all this work he subsequently shared with Marconi the 1909 Nobel Prize for Physics.Around 1895 he carried out experiments using a torsion balance in order to measure the universal gravitational constant, g, but the work for which he is probably best known is the addition of deflecting plates and a fluorescent screen to the Crooke's tube in 1897 in order to study the characteristics of high-frequency currents. The oscilloscope, as it was called, was not only the basis of a now widely used and highly versatile test instrument but was the forerunner of the cathode ray tube, or CRT, used for the display of radar and television images.At the beginning of the First World War, while in New York to testify in a patent suit, he was trapped by the entry of the USA into the war and remained in Brooklyn with his son until his death.[br]Principal Honours and DistinctionsNobel Prize for Physics (jointly with Marconi) 1909.Bibliography1874, "Assymetrical conduction of certain metal sulphides", Pogg. Annal. 153:556 (provides an account of the discovery of the crystal rectifier).1897, "On a method for the demonstration and study of currents varying with time", Wiedemann's Annalen 60:552 (his description of the cathode ray oscilloscope as a measuring tool).Further ReadingK.Schlesinger \& E.G.Ramberg, 1962, "Beamdeflection and photo-devices", Proceedings of the Institute of Radio Engineers 50, 991.KF -
2 Electricity
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3 Electronics and information technology
See also: INDEX BY SUBJECT AREA[br]Byron, Ada AugustaNapier, JohnRiche, Gaspard-Clair-François-MarieSchickhard, WilhelmBiographical history of technology > Electronics and information technology
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4 Telecommunications
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5 Crookes, Sir William
SUBJECT AREA: Electricity[br]b. 17 June 1832 London, Englandd. 4 April 1919 London, England[br]English chemist and physicist who carried out studies of electrical discharges and cathode rays in rarefied gases, leading to the development of the cathode ray tube; discoverer of the element thallium and the principle of the Crookes radiometer.[br]Crookes entered the Royal College of Chemistry at the age of 15, and from 1850 to 1854 held the appointment of Assistant at the college. In 1854 he became Superintendent of the Meteorological Department at the Radcliffe Observatory in Oxford. He moved to a post at the College of Science in Chester the following year. Soon after this he inherited a large fortune and set up his own private laboratory in London. There he studied the nature of electrical discharges in gases at low pressure and discovered the dark space (later named after him) that surrounds the negative electrode, or cathode. He also established that the rays produced in the process (subsequently shown by J.J.Thompson to be a stream of electrons) not only travelled in straight lines, but were also capable of producing heat and/or light upon impact with suitable anode materials. Using a variety of new methods to investigate these "cathode" rays, he applied them to the spectral analysis of compounds of selenium and, as a result, in 1861 he discovered the element thallium, finally establishing its atomic weight in 1873. Following his discovery of thallium, he became involved in two main lines of research: the properties of rarified gases, and the investigation of the elements of the "rare earths". It was also during these experiments that he discovered the principle of the Crookes radiometer, a device in which light is converted into rotational motion and which used to be found frequently in the shop windows of English opticians. Also among the fruits of this work were the Crookes tubes and the development of spectacle lenses with differential ranges of radiational absorption. In the 1870s he became interested in spiritualism and acquired a reputation for his studies of psychic phenomena, but at the turn of the century he returned to traditional scientific investigations. In 1892 he wrote about the possibility of wireless telegraphy. His work in the field of radioactivity led to the invention of the spinthariscope, an early type of detector of alpha particles. In 1900 he undertook investigations into uranium which led to the study of scintillation, an important tool in the study of radioactivity.While the theoretical basis of his work has not stood the test of time, his material discoveries, observations and investigations of new facts formed a basis on which others such as J.J. Thomson were to develop subatomic theory. His later involvement in the investigation of spiritualism led to much criticism, but could be justified on the basis of a belief in the duty to investigate all phenomena.[br]Principal Honours and DistinctionsKnighted 1897. Order of Merit 1910. FRS 1863. President, Royal Society 1913–15. Honorary LLD Birmingham. Honorary DSc Oxon, Cambridge, Sheffield, Durham, Ireland and Cape of Good Hope.Bibliography1874, On Attraction and Repulsion Resulting from Radiation.1874, "Researches in the phenomenon of spiritualism", Society of Metaphysics; reprinted in facsimile, 1986.For many years he was also Proprietor and Editor of Chemical News.Further ReadingE.E.Fournier D'Albe, 1923, Life of Sir William Crookes. Who Was Who II, 1916–28, London: A. \& C. Black. T.I.Williams, 1969, A Biographical Dictionary of Scientists. See also Braun, Karl Ferdinand.KF / MG
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Braun , Karl Ferdinand — (1850–1918) German physicist Braun, who was born in Fulda, Germany, studied at Marburg and, in 1872, received a doctorate from the University of Berlin. He taught in various university posts. In 1885 he became professor of experimental physics at … Scientists
Braun, Karl Ferdinand — ► (1850 1918) Físico alemán. Fue premio Nobel de Física en 1909, compartido con Marconi, por las modificaciones introducidas en la telegrafía sin hilos … Enciclopedia Universal
Karl Ferdinand Braun — (* 6. Juni 1850 in Fulda; † 20. April 1918 in New York City) war ein deutscher Physiker, Elektrotechniker und Nobelpreisträger, der im besonderen Maße daran mitwirkte, die von Heinrich Hertz 1888 experimentell nachgewiesene elektromagnetische… … Deutsch Wikipedia
Karl Ferdinand Braun — Ferdinand Braun Pour les articles homonymes, voir Braun. Ferdinand Braun Karl Ferdinand Braun (6 mai … Wikipédia en Français
Karl Ferdinand Braun — Infobox Scientist name = Karl Ferdinand Braun imagesize = 180px caption = Ferdinand Braun birth date = birth date|1850|6|6|mf=y birth place = Fulda, Hesse Kassel (or Hesse Cassel), Germany death date = death date and age|1918|4|20|1850|6|6 death… … Wikipedia
Braun — Karl Ferdinand … Scientists
Ferdinand Braun — Karl Ferdinand Braun (* 6. Juni 1850 in Fulda; † 20. April 1918 in New York) war ein deutscher Physiker, Elektrotechniker und Nobelpreisträger (1909, gemeinsam mit Guglielmo Marconi), der im besonderen Maße daran mitwirkte, d … Deutsch Wikipedia
Braun — Braun, Karl Ferdinand Braun, Wernher von Braun, tubo de * * * (as used in expressions) Braun, Eva Braun, Wernher von Sanford Braun … Enciclopedia Universal
Braun — (Karl Ferdinand) (1850 1918) physicien allemand. Il mit au point l oscillographe cathodique (1897). P. Nobel 1909. Braun (Wernher von) (1912 1977) ingénieur allemand; le père du V2 (1944 1945). En 1945, il fut emmené aux È. U., où il collabora à… … Encyclopédie Universelle
Braun'sche Röhre — Die Artikel Kathodenstrahlröhre und Kathodenstrahlröhrenbildschirm überschneiden sich thematisch. Hilf mit, die Artikel besser voneinander abzugrenzen oder zu vereinigen. Beteilige dich dazu an der Diskussion über diese Überschneidungen. Bitte… … Deutsch Wikipedia
Karl Braun — ist der Name folgender Personen: Karl Braun (Sachsen) (1807–1868), sächsischer Politiker und Regierungschef Karl Braun (NLP) (1822–1893), hessen nassauischer Politiker Karl Braun (Gynäkologe) (1823–1891), österreichischer Gynäkologe Karl Braun… … Deutsch Wikipedia