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1 Hertz, Heinrich Rudolph
[br]b. 22 February 1857 Hamburg, Germanyd. 1 January 1894 Bonn, Germany[br]German physicist who was reputedly the first person to transmit and receive radio waves.[br]At the age of 17 Hertz entered the Gelehrtenschule of the Johaneums in Hamburg, but he left the following year to obtain practical experience for a year with a firm of engineers in Frankfurt am Main. He then spent six months at the Dresden Technical High School, followed by year of military service in Berlin. At this point he decided to switch from engineering to physics, and after a year in Munich he studied physics under Helmholtz at the University of Berlin, gaining his PhD with high honours in 1880. From 1883 to 1885 he was a privat-dozent at Kiel, during which time he studied the electromagnetic theory of James Clerk Maxwell. In 1885 he succeeded to the Chair in Physics at Karlsruhe Technical High School. There, in 1887, he constructed a rudimentary transmitter consisting of two 30 cm (12 in.) rods with metal balls separated by a 7.5 mm (0.3 in.) gap at the inner ends and metallic plates at the outer ends, the whole assembly being mounted at the focus of a large parabolic metal mirror and the two rods being connected to an induction coil. At the other side of his laboratory he placed a 70 cm (27½ in.) diameter wire loop with a similar air gap at the focus of a second metal mirror. When the induction coil was made to create a spark across the transmitter air gap, he found that a spark also occurred at the "receiver". By a series of experiments he was not only able to show that the invisible waves travelled in straight lines and were reflected by the parabolic mirrors, but also that the vibrations could be refracted like visible light and had a similar wavelength. By this first transmission and reception of radio waves he thus confirmed the theoretical predictions made by Maxwell some twenty years earlier. It was probably in his experiments with this apparatus in 1887 that Hertz also observed that the voltage at which a spark was able to jump a gap was significantly reduced by the presence of ultraviolet light. This so-called photoelectric effect was subsequently placed on a theoretical basis by Albert Einstein in 1905. In 1889 he became Professor of Physics at the University of Bonn, where he continued to investigate the nature of electric discharges in gases at low pressure until his death after a long and painful illness. In recognition of his measurement of radio and other waves, the international unit of frequency of an oscillatory wave, the cycle per second, is now universally known as the Hertz.[br]Principal Honours and DistinctionsRoyal Society Rumford Medal 1890.BibliographyMuch of Hertz's work, including his 1890 paper "On the fundamental equations of electrodynamics for bodies at rest", is recorded in three collections of his papers which are available in English translations by D.E.Jones et al., namely Electric Waves (1893), Miscellaneous Papers (1896) and Principles of Mechanics (1899).Further ReadingJ.G.O'Hara and W.Pricha, 1987, Hertz and the Maxwellians, London: Peter Peregrinus. J.Hertz, 1977, Heinrich Hertz, Memoirs, Letters and Diaries, San Francisco: San Francisco Press.R.Appleyard, 1930, Pioneers of Electrical Communication.See also: Heaviside, OliverKFBiographical history of technology > Hertz, Heinrich Rudolph
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2 hertz
m.hertz.m. s.&pl.1 hertz, Hz.2 Hertz, Gustav Ludwig Hertz.3 Hertz, Heinrich Rudolph Hertz.* * *1 hertz* * */ˈxerts/,hertz* * *hertz* * *m FÍS hertz -
3 Heinrich Hertz
n. Heinrich Hertz, Heinrich Rudolph Hertz (1857-1894), Duitse natuurkundige, de eerste die elektromagnetische golven op kunstmatige wijze gebruikte -
4 Heinrich Hertz
m.Heinrich Hertz, Heinrich Rudolph Hertz. -
5 hertz
n. Hertz, familienaam; Heinrich Rudolph Hertz (1857-1894), Duitse natuurkundige, eerste persoon die elektromagnetische golven op kunstmatige manier heeft geproduceerd[ hə:ts] 〈meervoud: hertz〉1 hertz -
6 Enrique Hertz
m.Heinrich Hertz, Heinrich Rudolph Hertz. -
7 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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8 Telecommunications
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9 Branly, Edouard Eugène
[br]b. 23 October 1844 Amiens, Franced. 24 March 1940 Paris, France[br]French electrical engineer, who c.1890 invented the coherer for detecting radio waves.[br]Branly received his education at the Lycée de Saint Quentin in the Département de l'Aisne and at the Henri IV College of Paris University, where he became a Fellow of the University, graduating as a Doctor of Physics in 1873. That year he was appointed a professor at the College of Bourges and Director of Physics Instruction at the Sorbonne. Three years later he moved to the Free School in Paris as Professor of Advanced Studies. In addition to these responsibilities, he qualified as an MD in 1882 and practised medicine from 1896 to 1916. Whilst carrying out experiments with Hertzian (radio) waves in 1890, Branly discovered that a tube of iron filings connected to a source of direct voltage only became conductive when the radio waves were present. This early form of rectifier, which he called a coherer and which needed regular tapping to maintain its response, was used to operate a relay when the waves were turned on and off by Morse signals, thus providing the first practical radio communication.[br]Principal Honours and DistinctionsPapal Order of Commander of St George 1899. Légion d'honneur, Chevalier 1900, Commandeur 1925. Osiris Prize (jointly with Marie Curie) 1903. Argenteuil Prize and Associate of the Royal Belgian Academy 1910. Member of the Academy of Science 1911. State Funeral at Notre Dame Cathedral.BibliographyAmongst his publications in Comptes rendus were "Conductivity of mediocre conductors", "Conductivity of gases", "Telegraphic conduction without wires" and "Conductivity of imperfect conductors realised at a distance by wireless by spark discharge of a capacitor".Further ReadingE.Hawkes, 1927, Pioneers of Wireless, London: Methuen. E.Larien, 1971, A History of Invention, London: Victor Gollancz.V.J.Phillips: 1980, Early Radio Wave Detectors, London: Peter Peregrinus.KF -
10 Electricity
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11 Lodge, Sir Oliver Joseph
[br]b. 12 June 1851 Penkhull, Staffordshire, Englandd. 22 August 1940 Lake, near Salisbury, Wiltshire, England[br]English physicist who perfected Branly's coherer; said to have given the first public demonstration of wireless telegraphy.[br]At the age of 8 Lodge entered Newport Grammar School, and in 1863–5 received private education at Coombs in Suffolk. He then returned to Staffordshire, where he assisted his father in the potteries by working as a book-keeper. Whilst staying with an aunt in London in 1866–7, he attended scientific lectures and became interested in physics. As a result of this and of reading copies of English Mechanic magazine, when he was back home in Hanley he began to do experiments and attended the Wedgewood Institute. Returning to London c. 1870, he studied initially at the Royal College of Science and then, from 1874, at University College, London (UCL), at the same time attending lectures at the Royal Institution.In 1875 he obtained his BSc, read a paper to the British Association on "Nodes and loops in chemical formulae" and became a physics demonstrator at UCL. The following year he was appointed a physics lecturer at Bedford College, completing his DSc in 1877. Three years later he became Assistant Professor of Mathematics at UCL, but in 1881, after only two years, he accepted the Chair of Experimental Physics at the new University College of Liverpool. There began a period of fruitful studies of electricity and radio transmission and reception, including development of the lightning conductor, discovery of the "coherent" effect of sparks and improvement of Branly's coherer, and, in 1894, what is said to be the first public demonstration of the transmission and reception (using a coherer) of wireless telegraphy, from Lewis's department store to the clock tower of Liverpool University's Victoria Building. On 10 May 1897 he filed a patent for selective tuning by self-in-ductance; this was before Marconi's first patent was actually published and its priority was subsequently upheld.In 1900 he became the first Principal of the new University of Birmingham, where he remained until his retirement in 1919. In his later years he was increasingly interested in psychical research.[br]Principal Honours and DistinctionsKnighted 1902. FRS 1887. Royal Society Council Member 1893. President, Society for Psychical Research 1901–4, 1932. President, British Association 1913. Royal Society Rumford Medal 1898. Royal Society of Arts Albert Medal 1919. Institution of Electrical Engineers Faraday Medal 1932. Fourteen honorary degrees from British and other universities.Bibliography1875, "The flow of electricity in a plane", Philosophical Magazine (May, June and December).1876, "Thermo-electric phenomena", Philosophical Magazine (December). 1888, "Lightning conductors", Philosophical Magazine (August).1889, Modern Views of Electricity (lectures at the Royal Institution).10 May 1897, "Improvements in syntonized telegraphy without line wires", British patent no. 11,575, US patent no. 609,154.1898, "Radio waves", Philosophical Magazine (August): 227.1931, Past Years, An Autobiography, London: Hodder \& Stoughton.Further ReadingW.P.Jolly, 1974, Sir Oliver Lodge, Psychical Resear cher and Scientist, London: Constable.E.Hawks, 1927, Pioneers of Wireless, London: Methuen.See also: Hertz, Heinrich RudolphKFBiographical history of technology > Lodge, Sir Oliver Joseph
См. также в других словарях:
Heinrich Rudolph Hertz — Heinrich Hertz Unterschrift von Heinrich Hertz Heinrich Rudolf Hertz (* 22. Februar 1857 in Hamburg; † 1. Januar … Deutsch Wikipedia
Heinrich Rudolph Hertz — Heinrich Rudolf Hertz Pour les articles homonymes, voir Hertz (homonymie). Heinrich Hertz … Wikipédia en Français
Heinrich Rudolph Hertz — noun German physicist who was the first to produce electromagnetic waves artificially (1857 1894) • Syn: ↑Hertz, ↑Heinrich Hertz • Derivationally related forms: ↑Hertzian (for: ↑Hertz) • Instance Hypernyms: ↑ … Useful english dictionary
Heinrich Rudolph Hertz — n. Heinrich Hertz (1857 1894), German physicist, first person who produced electromagnetic waves in an artificial manner … English contemporary dictionary
HERTZ (H. R.) — HERTZ HEINRICH RUDOLPH (1857 1894) Physicien allemand (oncle de Gustav Hertz, lauréat du prix Nobel de physique en 1925) né à Hambourg et mort à Bonn. Heinrich Rudolph Hertz, après des études d’ingénieur, abandonne cette branche pour la physique … Encyclopédie Universelle
Heinrich Hertz — Infobox Scientist name = Heinrich Rudolf Hertz image width = 230px birth date = birth date|1857|2|22|mf=y birth place = Hamburg, Germany residence = Germany nationality = German death date = death date and age|1894|1|1|1857|2|22|mf=y death place … Wikipedia
Heinrich Hertz — noun German physicist who was the first to produce electromagnetic waves artificially (1857 1894) • Syn: ↑Hertz, ↑Heinrich Rudolph Hertz • Derivationally related forms: ↑Hertzian (for: ↑Hertz) • Instance Hypernyms … Useful english dictionary
HERTZ, GUSTAV — (1887–1975), German physicist and Nobel Prize winner, son of a Jewish father. Born in Hamburg, he became an assistant in the Physical Institute at Berlin in 1913. He was severely wounded in World War I, and subsequently worked at Eindhoven in… … Encyclopedia of Judaism
Hertz — (izg. hȅrc) DEFINICIJA 1. Gustav (1887 1975), njemački atomski fizičar, Nobelova nagrada 1925 (s J. Franckom) 2. Heinrich Rudolph (1857 1894), njemački fizičar … Hrvatski jezični portal
Hertz — Hertzian /herrt see euhn, hairt /, adj. /herrts, hairts/; Ger. /herddts/, n. 1. Gustav /goos tahf/, 1887 1975, German physicist: Nobel prize 1925. 2. Heinrich Rudolph /huyn rddikh rddooh dawlf/, 1857 94, German physicist. * * * ▪ unit of… … Universalium
Heinrich Hertz — n. Heinrich Rudolph Hertz (1857 1894), German physicist, first person who produced electromagnetic waves in an artificial manner … English contemporary dictionary
