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Thermo Galvanometer
The thermo-galvanometer is an instrument for measuring small electric currents. It was invented by William Duddell about 1900. The following is a description of the instrument taken from a trade catalog of Cambridge Scientific Instrument Company dated 1905: For a long time the need of an instrument capable of accurately measuring small alternating currents has been keenly felt. The high resistance and self-induction of the coils of instruments of the electro-magnetic type frequently prevent their use. Electro-static instruments as at present constructed are not altogether suitable for measuring very small currents, unless a sufficient potential difference is available. The thermo-galvanometer designed by Mr W. Duddell can be used for the measurement of extremely small currents to a high degree of accuracy. It has practically no self-induction or capacity and can therefore be used on a circuit of any frequency (even up to 120,000~ per sec.) and currents as small as twenty micro- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge Thermo Galvanometer 1905
Cambridge ( ) is a university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cambridge became an important trading centre during the Roman and Viking ages, and there is archaeological evidence of settlement in the area as early as the Bronze Age. The first town charters were granted in the 12th century, although modern city status was not officially conferred until 1951. The city is most famous as the home of the University of Cambridge, which was founded in 1209 and consistently ranks among the best universities in the world. The buildings of the university include King's College Chapel, Cavendish Laboratory, and the Cambridge University Library, one of the largest legal deposit libraries in the world. The city's skyline is dominated by several college buildings, along with the spire of the Our Lady and the English Martyrs Chu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Duddell
William Du Bois Duddell (1 July 1872, in Kensington, London – 4 November 1917, in Wandsworth, London) was an English physicist and electrical engineer. His inventions include the moving coil oscillograph, as well as the thermo-ammeter and thermo-galvanometer. Life and career Duddell was born William Du Bois to Frances Kate Du Bois, who married George Duddell in 1881. At the age of four he constructed an automaton by combining a toy mouse with clockwork. His younger sister Gladys Duddell was a tennis player. Duddell was privately educated in England and France and rose quickly through the prestigious City & Guilds Schools via scholarships. He died at the age of 45. Duddell's "singing arc" Prior to the invention of the incandescent light bulb, arc lamps were used to light the streets. They created light using an electrical arc between two carbon electrodes. These lamps often produced audible humming, hissing, or even howling sounds. In 1899 Duddell, a student of Wil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge Scientific Instrument Company
Cambridge Scientific Instrument Company was a company founded in the late 1870s by Robert Fulcher. The original use of the company was to service instruments for the Cambridge physiology department. In the beginning, the company was financially driven by a friend of Horace Darwin (1851–1928), Albert Dew-Smith (1848–1903). Eventually, Fulcher was fully replaced in the company by Darwin and Dew-Smith, in 1881, who would then become the sole co-owners. In light of the company being taken over, by Darwin and Dew-Smith, it grew in regard and size. By the time the company was about 15 years old, in 1891, Horace Darwin became the sole owner of the company. Darwin, the son of Charles Darwin, was first apprenticed to an engineering firm in Kent, and returned to Cambridge in 1875. Dew-Smith was an engineer, photographer and instrument maker who was at Trinity College, Cambridge with Darwin. Darwin's grandson Erasmus Darwin Barlow was later chairman. Designed between 1883/84, the rock ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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