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Beam Tetrode
A beam tetrode, sometimes called a beam power tube, is a type of vacuum tube or thermionic valve that has two grids and forms the electron stream from the cathode into multiple partially collimated beams to produce a low potential space charge region between the anode and screen grid to return anode secondary emission electrons to the anode when the anode potential is less than that of the screen grid.Winfield G. Wagener, (May 1948"500-Mc. Transmitting Tetrode Design Considerations" ''Proceedings of the I.R.E.'', p. 612. Retrieved 10 June 2021 Beam tetrodes are usually used for power amplification, from audio frequency to radio frequency. The beam tetrode produces greater output power than a triode or pentode with the same anode supply voltage. The first beam tetrode marketed was the Marconi N40, introduced in 1935.Editors, (Feb. 1935"New Output Tetrode" ''Electronics'', vol. 8 no.2, p. 65. Retrieved 10 June 2021K. R. Thrower, (2009) ''British Radio Valves The Classic Year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eimac
Eimac is a trade mark of Eimac Products, part of the Microwave Power Products Division of Communications & Power Industries. It produces power vacuum tubes for radio frequency applications such as broadcast and radar transmitters. The company name is an initialism from the names of the founders, William Eitel and Jack McCullough. History The San Francisco Bay area was one of the early centers of amateur radio activity and experimentation, containing about 10% of the total operators in the US. Amateur radio enthusiasts sought vacuum tubes that would perform at higher power and on higher frequencies than those then available from RCA, Western Electric, General Electric, and Westinghouse. Additionally, they required tubes that would operate with the limited voltages available from typical amateur power supplies. While employed by the small San Francisco, California manufacturing firm of Heintz & Kaufman which manufactured custom radio equipment, Bill Eitel (amateur radio call sign W6U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screen Grid
A tetrode is a vacuum tube (called ''valve'' in British English) having four active electrodes. The four electrodes in order from the centre are: a thermionic cathode, first and second grids and a plate (called ''anode'' in British English). There are several varieties of tetrodes, the most common being the screen-grid tube and the beam tetrode. In screen-grid tubes and beam tetrodes, the first grid is the control grid and the second grid is the screen grid. In other tetrodes one of the grids is a control grid, while the other may have a variety of functions. The tetrode was developed in the 1920s by adding an additional grid to the first amplifying vacuum tube, the triode, to correct limitations of the triode. During the period 1913 to 1927, three distinct types of tetrode valves appeared. All had a normal control grid whose function was to act as a primary control for current passing through the tube, but they differed according to the intended function of the other grid. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, massa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Top Cap
A spinning top, or simply a top, is a toy with a squat body and a sharp point at the bottom, designed to be spun on its vertical axis, balancing on the tip due to the gyroscopic effect. Once set in motion, a top will usually wobble for a few seconds, spin upright for a while, then start to wobble again with increasing amplitude as it loses energy, and finally tip over and roll on its side. Tops exist in many variations and materials, chiefly wood, metal, and plastic, often with a metal tip. They may be set in motion by twirling a handle with the fingers, by pulling a rope coiled around the body, or by means of a built-in auger (spiral plunger). Such toys have been used since antiquity in solitary or competitive games, where each player tries to keep one's top spinning for as long as possible, or achieve some other goal. Some tops have faceted bodies with symbols or inscriptions, and are used like dice to inject randomness into games, or for divination and ritual purposes. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio-frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper limit of audio frequencies and the lower limit of infrared frequencies; these are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves. Different sources specify different upper and lower bounds for the frequency range. Electric current Electric currents that oscillate at radio frequencies (RF currents) have special properties not shared by direct current or lower audio frequency alternating current, such as the 50 or 60 Hz current used in electrical power distribution. * Energy from RF currents in conductors can radiate into space as electromagnetic waves ( radio waves). This is the basis of radio technology. * RF current does not penetrate deeply into electrical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
807 (vacuum Tube)
__NOTOC__ Year 807 ( DCCCVII) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. Events By place Abbasid Empire and Byzantine Empire * Emperor Nikephoros I is forced to sue for peace, on condition of paying 50,000 '' nomismata'' to Caliph Harun al-Rashid, and agrees to a yearly tribute. Nikephoros promises not to rebuild the dismantled forts. Rashid recalls his forces from various sieges, and evacuates Byzantine territory.. * An Abbasid fleet under Humayd ibn Ma'yuf al-Hajuri raids the Peloponnese, Rhodes and Myra. Europe * Al-Andalus (modern Spain): An uprising occurs in the city of Mérida against the Umayyad Emirate of Córdoba. * Siege of Patras: This marks the end of independent rule by the South Slavs in the Peloponnese (or 805). Britain * The Vikings land on the Cornish coast, and form an alliance with the Cornish to fight against Wessex. * King Cuthred of Kent dies. His brother, King Coenwulf of Mercia, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
All American Five
The term All American Five (abbreviated AA5) is a colloquial name for mass-produced, superheterodyne radio receivers that used five vacuum tubes in their design. These radio sets were designed to receive amplitude modulation (AM) broadcasts in the medium wave band, and were manufactured in the United States from the mid-1930s until the early 1960s. By eliminating a power transformer, cost of the units was kept low; the same principle was later applied to television receivers. Variations in the design for lower cost, shortwave bands, better performance or special power supplies existed, although many sets used an identical set of vacuum tubes. Philosophy The radio was called the "All American Five" because the design typically used five vacuum tubes, and comprised the majority of radios manufactured for home use in the USA and Canada in the tube era. They were manufactured in the millions by hundreds of manufacturers from the 1930s onward, with the last examples being made in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
25L6
The 25L6 is an octal-based vacuum tube of the Beam tetrode type. It is the Octal base equivalent to thtype '43 power tubewhich made early AC-powered loudspeaker radios affordable. It found common application in AC/DC radio receivers - such as those of the All American Five type - and was also found in large numbers in early computers, such as the UNIVAC I. The tube used EIA base 7AC in common with many other power tubes. The tube was identical in design and ratings with the 50L6 with the exception of having a 25 volt 300 mA heater, whereas the 50L6 has a 50 volt 150 mA heater. The 12L6 and identical 12W6 were made with a 12 volt, 600 mA heater, and the 6W6 was made with a 6.3V, 1200mA heater. There was also a 35L6 with a 35V, 150 mA heater. Because of the slightly lower-power heater, the 35L6 has slightly lower output than the rest of the family. This family is not to be confused with the 6L6, which has the same basing diagram, but has more than twice the power capability ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EL34
The EL34 is a thermionic vacuum tube of the power pentode type. The EL34 was introduced in 1955 by Mullard, who were owned by Philips. The EL34 has an octal base (indicated by the '3' in the part number) and is found mainly in the final output stages of audio amplification circuits; it was also designed to be suitable as a series regulator by virtue of its high permissible voltage between heater and cathode and other parameters. The American RETMA tube designation number for this tube is 6CA7. The USSR analog was 6P27S (Cyrillic: 6П27C). Specifications In common with all 'E' prefix tubes, using the Mullard–Philips tube designation, the EL34 has a heater voltage of 6.3 V. According to the data sheets found in old vacuum tube reference manuals, a pair of EL34s with 800 V plate voltage can produce 90 watts output in class AB1 in push–pull configuration. However, this configuration is rarely found. One application of this type was in "Australian Sound" public address amplifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KT88
The KT88 is a beam tetrode/kinkless tetrode (hence "KT") vacuum tube for audio amplification. Features The KT88 fits a standard eight-pin octal socket and has similar pinout and applications as the 6L6 and EL34. Specifically designed for audio amplification, the KT88 has higher plate power and voltage ratings than the American 6550. It is one of the largest tubes in its class and can handle significantly higher plate voltages than similar tubes, up to 800 volts. A KT88 push-pull pair in class AB1 fixed bias is capable of 100 watts of output with 2.5% total harmonic distortion or up to about 50W at low distortion in hi-fi applications. The transmitting tubes TT21 and TT22 have almost identical transfer characteristics to KT88 but a different pinout, and by virtue of their anode being connected to the top cap have a higher plate voltage rating (1.25 kilovolt) and a higher power output capability of 200 watts in class AB1 push–pull. The screen grid is sometimes tied to the an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KT66
KT66 is the designator for a beam power tube introduced by Marconi-Osram Valve Co. Ltd. (M-OV) of Britain in 1937 and marketed for application as a power amplifier for audio frequencies and driver for radio frequencies.Editors "The New Valves" ''Wireless World'', August 20th 1937, p. 178General Electric Co., Ltd."Osram Valves" ''Television and Short-Wave World'', Sept. 1939, p. 524 The KT66 is a beam tetrode that utilizes partially collimated electron beams to form a low potential space charge region between the anode and screen grid to return anode secondary emission electrons to the anode and offers significant performance improvements over comparable power pentodes.Dreyer, J. F. Jr."The Beam Power Output Tube" ''Electronics'', Vol. 9, No. 4, April 1936, pp. 18 - 21, 35 In the 21st century, the KT66 is manufactured and used in some high fidelity audio amplifiers and musical instrument amplifiers. Overview Although the RCA 6L6 of 1936 (the result of a license agreement between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Electric Company Plc
The General Electric Company (GEC) was a major British industrial conglomerate involved in consumer and defence electronics, communications, and engineering. The company was founded in 1886, was Britain's largest private employer with over 250,000 employees in the 1980s, and at its peak in the 1990s, made profits of over £1 billion a year. In June 1998, GEC sold its share of the joint venture GEC-Alsthom on the Paris stock exchange. In December 1999, GEC's defence arm, Marconi Electronic Systems, was sold to British Aerospace, forming BAE Systems. The rest of GEC, mainly telecommunications equipment manufacturing, continued as Marconi Communications. After buying several US telecoms manufacturers at the top of the market, losses following the bursting of the dot-com bubble in 2001 led to the restructuring in 2003 of Marconi plc into Marconi Corporation plc. In 2005, Ericsson acquired the bulk of that company. What was left of the business was renamed Telent. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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