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Pentagrid Converter
The pentagrid converter is a type of radio receiving valve (vacuum tube) with five grids used as the frequency mixer stage of a superheterodyne radio receiver. The pentagrid was part of a line of development of valves that were able to take an incoming RF signal and change its frequency to a fixed intermediate frequency, which was then amplified and detected in the remainder of the receiver circuitry. The device was generically referred to as a ''frequency changer'' or just ''mixer''. Origins The first devices designed to change frequency in the manner described above seem to have been developed by the French, who simply put two grids into what would otherwise have been an ordinary triode valve (the bi-grille or bi-grid). Although technically a four electrode device, neither the term tetrode nor the tetrode valve as it is known today had yet appeared. The bi-grid differed from the later tetrode because the second (outer) grid was coarsely wound compared with the tetrode's scr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heptode Pentagrid
The pentagrid converter is a type of radio receiving valve (vacuum tube) with five grids used as the frequency mixer stage of a superheterodyne radio receiver. The pentagrid was part of a line of development of valves that were able to take an incoming RF signal and change its frequency to a fixed intermediate frequency, which was then amplified and detected in the remainder of the receiver circuitry. The device was generically referred to as a ''frequency changer'' or just ''mixer''. Origins The first devices designed to change frequency in the manner described above seem to have been developed by the French, who simply put two grids into what would otherwise have been an ordinary triode valve (the bi-grille or bi-grid). Although technically a four electrode device, neither the term tetrode nor the tetrode valve as it is known today had yet appeared. The bi-grid differed from the later tetrode because the second (outer) grid was coarsely wound compared with the tetrode's scr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Valve Association
The British Radio and Valve Manufacturers' Association (BVA) was a 20th-century cartel of vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as ... (valve) manufacturers in the United Kingdom of Great Britain and Northern Ireland (UK) that was designed to protect their interests from foreign competition. This cartel dictated (among other things), the price of valves (vacuum tubes) and how they were numbered. The numbering scheme was supposedly designed to make it difficult to identify American equivalents, which were typically half the retail price in their home country; however American types manufactured in the UK by companies such as Brimar sold at the same price as their UK counterparts due to the BVA's insistence. All manufacturers eventually published their own lists of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentode
A pentode is an electronic device having five electrodes. The term most commonly applies to a three-grid amplifying vacuum tube or thermionic valve that was invented by Gilles Holst and Bernhard D.H. Tellegen in 1926. The pentode (called a ''triple-grid amplifier'' in some literature) was developed from the ''screen-grid tube'' or ''shield-grid tube'' (a type of tetrode tube) by the addition of a grid between the screen grid and the plate. The screen-grid tube was limited in performance as an amplifier due to secondary emission of electrons from the plate. The additional grid is called the ''suppressor grid''. The suppressor grid is usually operated at or near the potential of the cathode and prevents secondary emission electrons from the plate from reaching the screen grid. The addition of the suppressor grid permits much greater output signal amplitude to be obtained from the plate of the pentode in amplifier operation than from the plate of the screen-grid tube at the same plat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transconductance
Transconductance (for transfer conductance), also infrequently called mutual conductance, is the electrical characteristic relating the current through the output of a device to the voltage across the input of a device. Conductance is the reciprocal of resistance. Transadmittance (or transfer admittance) is the AC equivalent of transconductance. Definition Transconductance is very often denoted as a conductance, ''g''m, with a subscript, m, for ''mutual''. It is defined as follows: :g_m = \frac For small signal alternating current, the definition is simpler: :g_m = \frac The SI unit for transconductance is the siemens, with the symbol S, as in conductance. Transresistance Transresistance (for transfer resistance), also infrequently referred to as mutual resistance, is the dual of transconductance. It refers to the ratio between a change of the voltage at two output points and a related change of current through two input points, and is notated as ''r''m: :r_m = \fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loctal Base
Tube sockets are electrical sockets into which vacuum tubes (electronic valves) can be plugged, holding them in place and providing terminals, which can be soldered into the circuit, for each of the pins. Sockets are designed to allow tubes to be inserted in only one orientation. They were used in most tube electronic equipment to allow easy removal and replacement. When tube equipment was common, retailers such as drug stores had vacuum tube testers, and sold replacement tubes. Some Nixie tubes were also designed to use sockets. Throughout the tube era, as technology developed, sometimes differently in different parts of the world, many tube bases and sockets came into use. Sockets are not universal; different tubes may fit mechanically into the same socket, though they may not work properly and possibly become damaged. Tube sockets were typically mounted in holes on a sheet metal chassis and wires or other components were hand soldered to lugs on the underside of the socket. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philco
Philco (an acronym for Philadelphia Battery Company) is an American electronics industry, electronics manufacturer headquartered in Philadelphia. Philco was a pioneer in battery, radio, and television production. In 1961, the company was purchased by Ford Motor Company, Ford and, from 1966, renamed "Philco-Ford". Ford sold the company to GTE in 1974, and it was purchased by Philips in 1981. In North America, the Philco brand is currently owned by Philips. In other markets, the Philco International brand is owned by Electrolux. In the early 1920s, Philco made storage batteries, "socket power" battery eliminator units (plug-in transformers), and battery chargers. With the invention of the rectifier tube, which made it practical to power radios by electrical outlets, in 1928, Philco entered the radio business. They followed other radio makers such as RCA, Atwater-Kent, Zenith Electronics, Freshman Masterpiece, FADA Radio (Frank A. D'Andrea Radio), and AH Grebe into the battery-powere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osram Sylvania
Osram Sylvania Inc. is the North American operation of lighting manufacturer Osram Osram Licht AG is a German company that makes electric lights, headquartered in Munich and Premstätten (Austria). Osram positions itself as a high-tech photonics company that is increasingly focusing on sensor technology, visualization and t .... It was established in January 1993, with the acquisition of GTE’s Sylvania lighting division by Osram GmbH. In 2016, Osram spun off their general lighting business to Ledvance which received a license to sell lighting products under the Osram and Sylvania names. The company produces lighting products for industrial, entertainment, medical, and smart building and city applications, as well as products for the automotive aftermarket and original equipment manufacturer markets. Osram Sylvania completed a move of their regional headquarters from Danvers, Massachusetts, to Wilmington, Massachusetts, on 12 October 2015. Company profile Osram S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixer Oktode
Mixer may refer to: Electronics * DJ mixer, a type of audio mixing console used by disc jockeys * Electronic mixer, electrical circuit for adding signal voltages * Frequency mixer, electrical circuit that creates new frequencies from two signals applied to it * Mixing console, an electronic device for combining sounds of different audio signals * Mix engineer, person who combines elements of recorded music into a final version * Mode scrambler, known as a mode mixer, telecommunications device for inducing mode coupling in an optical fiber * Sound card mixer, analog part of a sound card that routes and mixes sound signals * Vision mixer, an electronic device for combining video signals Industrial and lab equipment * Concrete mixer, a machine which combines the ingredients of concrete, a.k.a. cement mixer * Feed mixer, for mixing feed ingredients * High-shear mixer, a device that disperse, or transports one phase or ingredient (liquid, solid, gas) into a main continuous phase ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osram
Osram Licht AG is a German company that makes electric lights, headquartered in Munich and Premstätten (Austria). Osram positions itself as a high-tech photonics company that is increasingly focusing on sensor technology, visualization and treatment by light. The company serves customers in the consumer, automotive, healthcare and industrial technology sectors. The operating company of Osram is Osram GmbH. Osram was founded in 1919 by the merger of the lighting businesses of Auergesellschaft, Siemens & Halske and Allgemeine Elektrizitäts-Gesellschaft (AEG). Osram was a wholly owned subsidiary of Siemens AG from 1978 to 2013. On 5 July 2013, Osram was spun off from Siemens, and the listing of its stock began on Frankfurt Stock Exchange on 8 July 2013. Osram's business with conventional light sources was spun off in 2016 under the name Ledvance and sold to a Chinese consortium. After a bidding war with Bain Capital, Osram was taken over by Austrian company AMS in July 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mullard
Mullard Limited was a British manufacturer of electronic components. The Mullard Radio Valve Co. Ltd. of Southfields, London, was founded in 1920 by Captain Stanley R. Mullard, who had previously designed thermionic valves for the Admiralty before becoming managing director of the Z Electric Lamp Co. The company soon moved to Hammersmith, London and then in 1923 to Balham, London. The head office in later years was Mullard House at 1–19 Torrington Place, Bloomsbury, now part of University College London. Start-up In 1921, the directors were Sir Ralph Ashton (chairman), Basil Binyon of the Radio Communication Co, C.F. Elwell and S.R. Mullard (Managing Director). Partnership with Philips In 1923, to meet the technical demands of the newly formed BBC, Mullard formed a partnership with the Dutch manufacturer Philips. The valves (vacuum tubes) produced in this period were named with the prefix PM, for Philips-Mullard, beginning with the PM3 and PM4 in 1926. Mullard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marconi-Osram Valve
M-OV (Marconi-Osram Valve Company) was a British manufacturer of thermionic valves (vacuum tubes). It was a subsidiary of the (British) General Electric Company Ltd. The company was founded in 1919, when the valve making interests of GEC (Osram) and the Marconi Company were combined. In 1929, Marconi sold its interest in the company to the Gramophone Company, a predecessor of EMI. In 1939, M-OV acquired two disused cotton mills at Shaw, Oldham where it established a shadow factory to produce valves and cathode ray tubes. The two mills named Cape and Duke, were bought from the Lancashire Cotton Corporation for £7,000. Cape mill was used as the main production facility at Shaw, with the adjacent Duke mill remaining mostly unused. Shaw produced a vast array of valves for the war effort, some of which are listed below. * VT104 and VT105 for the T1154 transmitter. * VR99, VR100, VR101 and VR103 for the R1155 receiver. * TT11 for the TR1143 fighter set. * VT90 micropup used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexode Symbol
The pentagrid converter is a type of radio receiving valve (vacuum tube) with five grids used as the frequency mixer stage of a superheterodyne radio receiver. The pentagrid was part of a line of development of valves that were able to take an incoming RF signal and change its frequency to a fixed intermediate frequency, which was then amplified and detected in the remainder of the receiver circuitry. The device was generically referred to as a ''frequency changer'' or just ''mixer''. Origins The first devices designed to change frequency in the manner described above seem to have been developed by the French, who simply put two grids into what would otherwise have been an ordinary triode valve (the bi-grille or bi-grid). Although technically a four electrode device, neither the term tetrode nor the tetrode valve as it is known today had yet appeared. The bi-grid differed from the later tetrode because the second (outer) grid was coarsely wound compared with the tetrode's scr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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