-
1 Duddell, William du Bois
SUBJECT AREA: Electricity[br]b. 1872 Kensington, London, Englandd. 4 November 1917 London, England[br]English engineer, inventor of the first practical oscillograph.[br]After an education at the College of Stanislas, Cannes, Duddell served an apprenticeship with Davy Paxman of Colchester. Studying under Ayrton and Mather at the Central Technical College in South Kensington, he found the facilities for experimental work of exceptional value to him and remained there for some years. In 1897 Duddell produced a galvanometer which was sufficiently responsive to display an alternating-current wave-form. This instrument, with a coil carrying a mirror in the air gap of a powerful electromagnet, had a small periodic time. An oscillating mirror driven by a synchronous motor spread out the deflection on a time-scale. This development became the first commercial oscillograph and brought Duddell into prominence as a first-rate designer of special instruments. The Duddell oscillograph remained in use until after the Second World War, examples being used for recording short-circuit tests on high-power switchgear and other rapidly varying or transient phenomena. His next important work was to collaborate with Professor Marchant at Liverpool University to investigate the characteristics of the electric arc. This led to the suggestion that, coupled to a resonant circuit, the electric arc could form a generator of high-frequency currents. This arrangement was later developed by Poulson for wireless telegraphy. Duddell spent the last years of his life on government research as a member of the Admiralty Board of Inventions and Research and also of the Inventions Board of the Ministry of Munitions.[br]Principal Honours and DistinctionsCBE 1916. FRS 1907. Royal Society Hughes Medal 1912. President, Institution of Electrical Engineers 1912 and 1913.Bibliography1897, Electrician, 39:636–8 (describes his oscillograph). 5 March 1898, British patent no. 5,449 (the oscillograph).1899, with E.W.Marchant, "Experiments on alternate current arcs by aid of oscillograph", Journal of the Institution of Electrical Engineers 28: 1–107.Further ReadingV.J.Phillips, 1987, Waveforms, Bristol (a comprehensive account).1945, "50 years of scientific instrument manufacture", Engineering, 159:461.GWBiographical history of technology > Duddell, William du Bois
-
2 Electricity
-
3 Joubert, Jules François
SUBJECT AREA: Electricity[br]b. 1834 Tours, Franced. 1910 Paris, France[br]French physicist, investigator of alternating-current wave-forms.[br]Joubert became Professor of Physics in the Collège Rollin, Paris, in 1874, a position he held until 1888. He was at one time General Secretary of the Société Française de Physique. In collaboration with Pasteur he began studies into the theories of germs and bacteria. In 1880 Joubert carried out research on wave-forms in alternating-current arc-lighting circuits. Reinventing a method previously used by earlier experimenters, including Wheatstone, he was, by a mechanical sampling technique, able to determine the voltage at different points in the cycle. By using a rotating contact on the alternator shaft, the angular position of which could be varied, the whole of the wave-form could be delineated. This successful technique was widely used for some thirty years.[br]Bibliography1880, "Sur les courants alternatifs et la force électromotive de l'arc électrique", Journal of Physics 9:297–303 (describes his experiments).Further Reading"Investigation of alternating current arcs", Electrician (1880) 5:151–2 (a report on Joubert's method).V.J.Phillips, 1987, Waveforms, Bristol (an extensive account of early methods of wave-form observation).W.Bulloch, 1938, The History of Bacteriology, Oxford; 1979, repub. New York.See also: Duddell, William du BoisGWBiographical history of technology > Joubert, Jules François
См. также в других словарях:
William Duddell — Duddell s devices … Wikipedia
William Duddell — William Du Bois Duddell (* 1. Juli 1872 in London; † 4. November 1917 ebenda) war ein englischer Elektrotechniker. Von 1893 bis 1901 lehrte er am City Guilds College und experimentierte dort eingehend mit elektro physikalischen Apparaturen. Er… … Deutsch Wikipedia
Duddell Medal and Prize — The Duddell Medal and Prize was a prize awarded annually by the Institute of Physics in the memory of William du Bois Duddell, the inventor of the electromagnetic oscillograph. The medal was instituted by the Council of The Physical Society in… … Wikipedia
Liste der Biografien/Du — Biografien: A B C D E F G H I J K L M N O P Q … Deutsch Wikipedia
Arco cantante — Este artículo o sección sobre música y tecnología necesita ser wikificado con un formato acorde a las convenciones de estilo. Por favor, edítalo para que las cumpla. Mientras tanto, no elimines este aviso puesto el 12 de noviembre de 2008.… … Wikipedia Español
Electromagnetic oscillograph — An electromagnetic oscillograph is an Oscillograph which measures variations of electric current by having it go through a magnetic coil. Variations in current induce momentum in the coil, which can be directly measured.The electromagnetic… … Wikipedia
Plasma speaker — Plasma speakers (sometimes called flame speakers if the source of the plasma is combustion rather than gas ionization) are a form of loudspeaker which vary the intensity of a plasma, rather than using a magnetic field to push or pull a… … Wikipedia
Arco cantante — El fisico británico William Du Bois Duddell (William Duddell) descubrió, en el transcurso de unas investigaciones, que, aplicando una variación de voltaje a una lámpara de arco, podían crear frecuencias audibles que podía controlar. Cuanta más… … Enciclopedia Universal
Liste bedeutender Ingenieure — Siehe auch: Liste von Erfindern, Liste der Biographien, Kategorie:Ingenieur, Erfinder, Konstrukteur, Liste Persönlichkeiten der Elektrotechnik Inhaltsverzeichnis A B C D E F G H I J K L M N O P Q R S T U V W … Deutsch Wikipedia
Liste Persönlichkeiten der Elektrotechnik — Liste von Persönlichkeiten, die Beiträge im Bereich der Elektrotechnik geleistet haben: Inhaltsverzeichnis A B C D E F G H I J K L M N O P Q R S T U V W X Y Z … Deutsch Wikipedia
Musique electronique — Musique électronique Histoire de la musique Origines de la musique Afrique Orient Occident Grèce antique Rome antique Musique classique Médiévale Renaissance Baroque Classique Ro … Wikipédia en Français
