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Image Dissector
An image dissector, also called a dissector tube, is a video camera tube in which photocathode emissions create an "electron image" which is then swept up, down and across an anode to produce an electrical signal representing the visual image. It employs magnetic fields to keep the electron image in focus, and later models used electron multiplier to pick up the electrons.Horowitz, Paul and Winfield Hill, ''The Art of Electronics'', Second Edition Cambridge University Press, 1989, pp. 1000-1001. . The term had also been used for other kinds of early video camera tubes. Dissectors were used only briefly for research in television systems before being replaced by different much more sensitive tubes based on the charge-storage phenomenon like the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farnsworth Image Dissector Tube
Farnsworth may refer to: Places * Farnsworth, Indiana, a ghost town * Farnsworth, Texas, an unincorporated community in the Texas Panhandle *Farnsworth Peak, a mountain located west of Salt Lake City, Utah People * Farnsworth (surname), a list of people and fictional characters * Farnsworth Donald (1952), American artist, inventor, papermaker * Farnsworth Wright (1888–1940), editor of the pulp magazine ''Weird Tales'' Other uses * Farnsworth Art Museum, Rockland, Maine * Farnsworth House (other), various places * Farnsworth Lantern Test, used to screen for color blindness *Farnsworth Middle School, Guilderland Central School District, Guilderland, New York * Farnsworth Metropark, near Toledo, Ohio *Farnsworth method of learning Morse code Morse code is a telecommunications method which Character encoding, encodes Written language, text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rudolf Hell
Rudolf Hell (19 December 1901 – 11 March 2002) was a German inventor and engineer. Career Hell was born in Eggmühl. From 1919 to 1923, he studied electrical engineering in Munich. He worked there from 1923 to 1929 as assistant of Prof. Max Dieckmann, with whom he operated a television station at the ''Verkehrsausstellung'' (lit.: "traffic exhibition") in Munich in 1925. In the same year Hell invented an apparatus called the '' Hellschreiber'', an early forerunner to impact dot matrix printers and faxes. Hell received a patent for the Hellschreiber in 1929. In the year 1929 he founded his own company in Babelsberg. After World War II he re-founded his company in Kiel. He kept on working as an engineer and invented machines for electronically controlled engraving of printing plates and an electronic photo typesetting system called ''digiset'' marketed in the US as ''VideoComp'' by RCA and later by III. He has received numerous awards such as the Knight Commander's Cro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franklin Institute
The Franklin Institute is a science museum and a center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and wikt:statesman, statesman Benjamin Franklin. It houses the Benjamin Franklin National Memorial. Founded in 1824, the Franklin Institute is one of the oldest centers of science education and development in the United States. Its chief astronomer is Derrick Pitts. History 19th century On February 5, 1824, Samuel Vaughan Merrick and William H. Keating founded the Franklin Institute of the State of Pennsylvania for the Promotion of the Artes Mechanicae, Mechanic Arts. The opening was chronicled by ''The Literary Chronicle for the Year 1824'': Begun in 1825, the institute was an important force in the professionalization of American science and technology through the nineteenth century, beginning with early investigations into steam engines and water power. In addition to conducting scientific inquiry, it fostered re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multipactor
The multipactor effect is a phenomenon in radio-frequency (RF) amplifier vacuum tubes and waveguides, where, under certain conditions, secondary electron emission in resonance with an alternating electromagnetic field leads to exponential electron multiplication, possibly damaging and even destroying the RF device. Description The multipactor effect occurs when electrons accelerated by radio-frequency (RF) fields are self-sustained in a vacuum (or near vacuum) via an electron avalanche caused by secondary electron emission. Valery D. Shemelin and Sergey A. Belomestnykh, Multipactor in Accelerating Cavities (Book 1 of a Series: Particle Acceleration and Detection) 1st ed. ISSN 1611-1052, Springer Nature Switzerland AG, 2020 The impact of an electron to a surface can, depending on its energy and angle, release one or more secondary electrons into the vacuum. These electrons can then be accelerated by the RF fields and impact with the same or another surface. Should the impact energ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Francisco
San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of 2024, San Francisco is the List of California cities by population, fourth-most populous city in the U.S. state of California and the List of United States cities by population, 17th-most populous in the United States. San Francisco has a land area of at the upper end of the San Francisco Peninsula and is the County statistics of the United States, fifth-most densely populated U.S. county. Among U.S. cities proper with over 250,000 residents, San Francisco is ranked first by per capita income and sixth by aggregate income as of 2023. San Francisco anchors the Metropolitan statistical area#United States, 13th-most populous metropolitan statistical area in the U.S., with almost 4.6 million residents in 2023. The larger San Francisco Bay Area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philo T
Philo of Alexandria (; ; ; ), also called , was a Hellenistic Jewish philosopher who lived in Alexandria, in the Roman province of Egypt. The only event in Philo's life that can be decisively dated is his representation of the Alexandrian Jews in a delegation to the Roman emperor Caligula in 40 CE following civil strife between the Jewish and Greek communities of Alexandria. Philo was a leading writer of the Hellenistic Jewish community in Alexandria, Egypt. He wrote expansively in Koine Greek on philosophy, politics, and religion in his time; specifically, he explored the connections between Greek Platonic philosophy and late Second Temple Judaism. For example, he maintained that the Greek-language Septuagint and the Jewish law still being developed by the rabbis of the period together serve as a blueprint for the pursuit of individual enlightenment. Philo's deployment of allegory to harmonize Jewish scripture, mainly the Torah, with Greek philosophy was the first documente ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television
Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, entertainment, news, and sports. The medium is capable of more than "radio broadcasting", which refers to an audio signal sent to radio receivers. Television became available in crude experimental forms in the 1920s, but only after several years of further development was the new technology marketed to consumers. After World War II, an improved form of black-and-white television broadcasting became popular in the United Kingdom and the United States, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion.Diggs-Brown, Barbara (2011''Strategic Public Relations: Audience Focused Practice''p. 48 In the mid-1960s, color broadcasting was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Museum, London
The Science Museum is a major museum on Exhibition Road in South Kensington, London. It was founded in 1857 and is one of the city's major tourist attractions, attracting 3.3 million visitors annually in 2019. Like other publicly funded national museums in the United Kingdom, the Science Museum does not charge visitors for admission, although visitors are requested to make a donation if they are able. Temporary exhibitions may incur an admission fee. It is one of the five museums in the Science Museum Group. Founding and history The museum was founded in 1857 under Bennet Woodcroft from the collection of the Royal Society of Arts and surplus items from the Great Exhibition as part of the South Kensington Museum, together with what is now the Victoria and Albert Museum. It included a collection of machinery which became the ''Museum of Patents'' in 1858, and the ''Patent Office Museum'' in 1863. This collection contained many of the most famous exhibits of what is now th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute Of Electrical Engineers
The Institution of Electrical Engineers (IEE) was a British professional organisation of electronics, electrical, manufacturing, and information technology professionals, especially electrical engineers. It began in 1871 as the Society of Telegraph Engineers. In 2006, it merged with the Institution of Incorporated Engineers and the new organisation is Institution of Engineering and Technology (IET). Notable past presidents have included Lord Kelvin (1889), Sir Joseph Swan (1898) and Sebastian de Ferranti (1910–11). Notable chairmen include John M. M. Munro (1910–11). History The IEE was founded in 1871 as the Society of Telegraph Engineers, changed its name in 1880 to the Society of Telegraph Engineers and Electricians and changed to the Institution of Electrical Engineers in 1888. It was Incorporated by a Royal Charter in 1921. In 1988 the Institution of Electrical Engineers (IEE) merged with the Institution of Electronic and Radio Engineers (IERE), originally th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field (physics)
In science, a field is a physical quantity, represented by a scalar (mathematics), scalar, vector (mathematics and physics), vector, or tensor, that has a value for each Point (geometry), point in Spacetime, space and time. An example of a scalar field is a weather map, with the surface temperature described by assigning a real number, number to each point on the map. A surface wind map, assigning an arrow to each point on a map that describes the wind velocity, speed and direction at that point, is an example of a vector field, i.e. a 1-dimensional (rank-1) tensor field. Field theories, mathematical descriptions of how field values change in space and time, are ubiquitous in physics. For instance, the electric field is another rank-1 tensor field, while electrodynamics can be formulated in terms of Mathematical descriptions of the electromagnetic field, two interacting vector fields at each point in spacetime, or as a Covariant formulation of classical electromagnetism, single-ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Field
An electric field (sometimes called E-field) is a field (physics), physical field that surrounds electrically charged particles such as electrons. In classical electromagnetism, the electric field of a single charge (or group of charges) describes their capacity to exert attractive or repulsive forces on another charged object. Charged particles exert attractive forces on each other when the sign of their charges are opposite, one being positive while the other is negative, and repel each other when the signs of the charges are the same. Because these forces are exerted mutually, two charges must be present for the forces to take place. These forces are described by Coulomb's law, which says that the greater the magnitude of the charges, the greater the force, and the greater the distance between them, the weaker the force. Informally, the greater the charge of an object, the stronger its electric field. Similarly, an electric field is stronger nearer charged objects and weaker f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charged Particle Beam
A charged particle beam is a spatially localized group of electrically charged particles that have approximately the same position, kinetic energy (resulting in the same velocity), and direction. The kinetic energies of the particles are much larger than the energies of particles at ambient temperature. The high energy and directionality of charged particle beams make them useful for many applications in particle physics (see Particle beam#Applications and Electron-beam technology). Such beams can be split into two main classes: # ''unbunched beams'' (''coasting beams'' or ''DC beams''), which have no longitudinal substructure in the direction of beam motion. # ''bunched beams'', in which the particles are distributed into pulses (bunches) of particles. Bunched beams are most common in modern facilities, since the most modern particle accelerators require bunched beams for acceleration. Assuming a normal distribution of particle positions and impulses, a charged particle bea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
