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Heterostructure Barrier Varactor
The heterostructure barrier varactor (HBV) is a semiconductor device which shows a variable capacitance with voltage bias, similar to a varactor diode. Unlike a diode, it has an anti-symmetric current-voltage relationship and a symmetric capacitance-voltage relationship, as shown in the graph to the right. The device was invented by Erik Kollberg together with Anders Rydberg in 1989 at Chalmers University of Technology. The inset of the figure shows the circuit schematic symbol of the HBV. From the symbol, one can conclude that the HBV consists of two, back to back, anti-serially connected rectifying diodes (such as Schottky diodes for instance). The gap in the middle of the diode symbol represents the inherent capacitance of the device. The electrical characteristics of the HBV are realized by separating two layers of a semiconductor material (A) with a layer of another semiconductor material (B). The band-gap of material (B) should be larger than for material (A). This results in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IV CV Of HBVmellan
IV may refer to: Businesses and organizations *Immigration Voice, an activist organization *Industrievereinigung, Federation of Austrian Industry *Intellectual Ventures, a privately held intellectual property company *InterVarsity Christian Fellowship *Irish Volunteers, a military organization *Italia Viva, an Italian centrist political party, led by former prime minister Matteo Renzi Music *Subdominant, in music theory Recordings * ''IV'' (The 1975 EP), 2013 * ''IV'' (The Aggrolites album), 2009 * ''IV'' (Angband album), 2020 * ''IV'' (BadBadNotGood album), 2016 * ''IV'' (Black Mountain album), 2016 * ''IV'' (Cypress Hill album), 1998 * ''IV'' (Diamond Rio album), 1996 * ''IV'' (Goatsnake album), 1998 * ''IV'' (Godsmack album), 2006 * ''IV'' (Hiroyuki Sawano album), 2021 * ''I.V.'' (Loma Prieta album), 2012 * ''IV'' (The Lookouts album), 1990 * ''IV'' (Maylene and the Sons of Disaster album), 2011 * ''IV'' (Ton Steine Scherben album), 1981 * ''IV'' (The Stranglers album), 1980 * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varactor Diode
In electronics, a varicap diode, varactor diode, variable capacitance diode, variable reactance diode or tuning diode is a type of diode designed to exploit the voltage-dependent capacitance of a reverse-biased p–n junction. Applications Varactors are used as voltage-controlled capacitors. They are commonly used in voltage-controlled oscillators, parametric amplifiers, and frequency multipliers. Voltage-controlled oscillators have many applications such as frequency modulation for FM transmitters and phase-locked loops. Phase-locked loops are used for the frequency synthesizers that tune many radios, television sets, and cellular telephones. The varicap was developed by the Pacific Semiconductor subsidiary of the Ramo Wooldridge Corporation who received a patent for the device in June 1961. The device name was also trademarked as the "Varicap" by TRW Semiconductors, the successor to Pacific Semiconductors, in October 1967. This helps explain the different names for the dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Even And Odd Functions
In mathematics, even functions and odd functions are functions which satisfy particular symmetry relations, with respect to taking additive inverses. They are important in many areas of mathematical analysis, especially the theory of power series and Fourier series. They are named for the parity of the powers of the power functions which satisfy each condition: the function f(x) = x^n is an even function if ''n'' is an even integer, and it is an odd function if ''n'' is an odd integer. Definition and examples Evenness and oddness are generally considered for real functions, that is real-valued functions of a real variable. However, the concepts may be more generally defined for functions whose domain and codomain both have a notion of additive inverse. This includes abelian groups, all rings, all fields, and all vector spaces. Thus, for example, a real function could be odd or even (or neither), as could a complex-valued function of a vector variable, and so on. The given e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalmers University Of Technology
Chalmers University of Technology ( sv, Chalmers tekniska högskola, often shortened to Chalmers) is a Swedish university located in Gothenburg that conducts research and education in technology and natural sciences at a high international level. The university has approximately 3100 employees and 10,000 students, and offers education in engineering, science, shipping, architecture and other management areas. Chalmers is coordinating the Graphene Flagship, the European Union's biggest research initiative to bring graphene innovation out of the lab and into commercial applications, and leading the development of a Swedish quantum computer. History The university was founded in 1829 following a donation by William Chalmers, a director of the Swedish East India Company. He donated part of his fortune for the establishment of an "industrial school". Chalmers is one of only three universities in Sweden which are named after a person, the other two being Karolinska Institutet and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schottky Diode
The Schottky diode (named after the German physicist Walter H. Schottky), also known as Schottky barrier diode or hot-carrier diode, is a semiconductor diode formed by the junction of a semiconductor with a metal. It has a low forward voltage drop and a very fast switching action. The cat's-whisker detectors used in the early days of wireless and metal rectifiers used in early power applications can be considered primitive Schottky diodes. When sufficient forward voltage is applied, a current flows in the forward direction. A silicon p–n diode has a typical forward voltage of 600–700 mV, while the Schottky's forward voltage is 150–450 mV. This lower forward voltage requirement allows higher switching speeds and better system efficiency. History Walter H. Schottky (1886–1976) in 1914, discovered an irregularity in the emission of thermions in a vacuum tube, now known as the Schottky effect. Construction A metal–semiconductor junction is formed between a metal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Multiplier
In electronics, a frequency multiplier is an electronic circuit that generates an output signal and that output frequency is a harmonic (multiple) of its input frequency. Frequency multipliers consist of a nonlinear circuit that distorts the input signal and consequently generates harmonics of the input signal. A subsequent bandpass filter selects the desired harmonic frequency and removes the unwanted fundamental and other harmonics from the output. Frequency multipliers are often used in frequency synthesizers and communications circuits. It can be more economical to develop a lower frequency signal with lower power and less expensive devices, and then use a frequency multiplier chain to generate an output frequency in the microwave or millimeter wave range. Some modulation schemes, such as frequency modulation, survive the nonlinear distortion without ill effect (but schemes such as amplitude modulation do not). Frequency multiplication is also used in nonlinear optics. The n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioastronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission. These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers. The discovery of the cosmic microwave background radiation, regarded as evidence for the Big Bang theory, was made through radio astronomy. Radio astronomy is conducted using large radio antennas referred to as radio telescopes, that are either used singularly, or with multiple linked telescopes utilizing the techniques of radio interferometry and aperture synthesis. The use of interferometry allows radio astronomy to achieve high angular resolution, as the resolving power of an interferometer is set by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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