|
Soft Sutton Tube
A Sutton tube, or reflex klystron, is a type of vacuum tube used to generate microwaves. It is a low-power device used primarily for two purposes; one is to provide a tuneable low-power frequency source for the local oscillators in receiver circuits, and the other, with minor modifications, as a switch that could turn on and off another microwave source. The second use, sometimes known as a soft Sutton tube or rhumbatron switch, was a key component in the development of microwave radar by Britain during World War II. Microwave switches of all designs, including these, are more generally known as T/R tubes or T/R cells. The Sutton tube is named for one of its inventors, Robert Sutton, an expert in vacuum tube design. The original klystron designs had been developed in the late 1930s in the US, and Sutton was asked to develop a tuneable version. He developed the first models in late 1940 while working at the Admiralty Signals and Radar Establishment. Sutton tubes were widely used in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intermediate Frequency
In communications and electronic engineering, an intermediate frequency (IF) is a frequency to which a carrier wave is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called heterodyning, resulting in a signal at the difference or beat frequency. Intermediate frequencies are used in superheterodyne radio receivers, in which an incoming signal is shifted to an IF for amplification before final detection is done. Conversion to an intermediate frequency is useful for several reasons. When several stages of filters are used, they can all be set to a fixed frequency, which makes them easier to build and to tune. Lower frequency transistors generally have higher gains so fewer stages are required. It's easier to make sharply selective filters at lower fixed frequencies. There may be several such stages of intermediate frequency in a superheterodyne receiver; t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling and melting point are the lowest among all the elements. It is the second lightest and second most abundant element in the observable universe (hydrogen is the lightest and most abundant). It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and in Jupiter, due to the very high nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, the vast majority of which was formed during t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Research Establishment
The Telecommunications Research Establishment (TRE) was the main United Kingdom research and development organization for radio navigation, radar, infra-red detection for heat seeking missiles, and related work for the Royal Air Force (RAF) during World War II and the years that followed. It was regarded as "the most brilliant and successful of the English wartime research establishments" under "Rowe, who saw more of the English scientific choices between 1935 and 1945 than any single man." The name was changed to Radar Research Establishment in 1953, and again to the Royal Radar Establishment in 1957. This article covers the precursor organizations and the Telecommunications Research Establishment up to the time of the name change. The later work at the site is described in the separate article about RRE. History TRE is best known for work on defensive and offensive radar. TRE also made substantial contributions to radio-navigation and to jamming enemy radio-navigation. Rad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herbert Wakefield Banks Skinner
Herbert Wakefield Banks Skinner (7 October 1900 – 20 January 1960) was a British physicist. Biography Skinner was born on 7 October 1900 at 15 Woodville Road, Ealing, the only son of George Herbert, director of the shoe firm Lilley & Skinner, and Mabel Elizabeth (née Knight). He was taught at home before starting school, age 9, at Durston House, from where he won a mathematical scholarship to Rugby School, Rugby in 1914. He entered Trinity College, Cambridge in 1919 to read natural sciences and mathematics; he graduated in 1922. Skinner’s research career started in the Cavendish Laboratory where, under the supervision of Charles Drummond Ellis, Charles D Ellis, he worked on the β-ray spectrum of radium B and C. Five years later, in 1927, he moved to the physics department of the University of Bristol, which was headed by Arthur Mannering Tyndall, Arthur M Tyndall and very well equipped. He investigated the excitation potentials of lithium and beryllium, and published th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clarendon Laboratory
The Clarendon Laboratory, located on Parks Road within the Science Area in Oxford, England (not to be confused with the Clarendon Building, also in Oxford), is part of the Department of Physics at Oxford University. It houses the atomic and laser physics, condensed matter physics, and biophysics groups within the Department, although four other Oxford Physics groups are not based in the Clarendon Lab. The Oxford Centre for Quantum Computation is also housed in the laboratory. Buildings The Clarendon Laboratory consists of two adjoining buildings, the Lindemann Building (named after Frederick Lindemann, 1st Viscount Cherwell) and the Grade II listed Townsend Building (named after Sir John Sealy Townsend). The Beecroft Building (named after Adrian Beecroft) is now immediately in front of the Lindemann Building, completed in 2018 and designed by Hawkins\Brown, with a budget of approximately £40 million. History The Clarendon is named after Edward Hyde, 1st Earl of Clarendon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spark Gap
A spark gap consists of an arrangement of two conducting electrodes separated by a gap usually filled with a gas such as air, designed to allow an electric spark to pass between the conductors. When the potential difference between the conductors exceeds the breakdown voltage of the gas within the gap, a spark forms, ionizing the gas and drastically reducing its electrical resistance. An electric current then flows until the path of ionized gas is broken or the current reduces below a minimum value called the "holding current". This usually happens when the voltage drops, but in some cases occurs when the heated gas rises, stretching out and then breaking the filament of ionized gas. Usually, the action of ionizing the gas is violent and disruptive, often leading to sound (ranging from a ''snap'' for a spark plug to thunder for a lightning discharge), light and heat. Spark gaps were used historically in early electrical equipment, such as spark gap radio transmitters, electr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Diode
A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used. Among many uses, diodes are found in rect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parabolic Dish
A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis. The parabolic reflector transforms an incoming plane wave travelling along the axis into a spherical wave converging toward the focus. Conversely, a spherical wave generated by a point source placed in the focus is reflected into a plane wave propagating as a collimated beam along the axis. Parabolic reflectors are used to collect energy from a distant source (for example sound waves or incoming star light). Since the principles of reflection are reversible, parabolic reflectors can also be used to collimate radiation from an isotropic source into a parallel beam. In optics, parabolic mirrors are used to gather light in reflecting telescopes and solar furnaces, and project a beam of light in flashl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bernard Lovell
Sir Alfred Charles Bernard Lovell (31 August 19136 August 2012) was an English physicist and radio astronomer. He was the first director of Jodrell Bank Observatory, from 1945 to 1980. Early life and education Lovell was born at Oldland Common, Bristol in 1913, the son of local tradesman and Methodist preacher Gilbert Lovell (1881-1956) and Emily Laura, née Adams. Gilbert Lovell was an "authority on the Bible" and, having "studied English literature and grammar", was still "bombarding his son with complaints on points of grammar, punctuation and method of speaking" when Lovell was in his forties. Lovell's childhood hobbies and interests included cricket and music, mainly the piano. He had a Methodist upbringing and attended Kingswood Grammar School. Career and research Lovell studied physics at the University of Bristol obtaining a Bachelor of Science degree in 1934, and a PhD in 1936 for his work on the electrical conductivity of thin films. At this time, he also receive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AI Mk
AI is artificial intelligence, intellectual ability in machines and robots. Ai, AI or A.I. may also refer to: Animals * Ai (chimpanzee), an individual experimental subject in Japan * Ai (sloth) or the pale-throated sloth, northern Amazonian mammal species Arts, entertainment and media Works * ''Ai'' (album), a 2004 release by Seraphim * ''A.I. Artificial Intelligence'', a 2001 American film * '' A.I. Rising'', a 2018 Serbian film * '' AI: The Somnium Files'', a 2019 video game * ''American Idol'', televised singing contest * ''The American Interest'', a bimonthly magazine (2005–2020) * ''I'' (2015 film), an Indian Tamil film (initial title: ''Ai'') Other uses in arts and media * A.i. (band), a Californian rock–electroclash group * All in (poker), wagering one's entire stake * Appreciation Index, a British measure of broadcast programme approval * The Art Institutes, a chain of American art schools * Non-player character, in gaming (colloquially, ''an AI'') Business * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
