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4-1000A
The 4-1000A/8166 is a radial-beam tetrode designed for use in radio transmitters. The 4-1000A is the largest of a series of tubes including the 4-65A, 4-125A, 4-250A, and the 4-400A. These tubes share a common naming convention in which the first number identifies the number of elements contained within the tube; ''i.e.'', the number “4” identifies the tube as a tetrode which contains four elements (filament, control grid, screen grid, and anode), and the second number indicates the maximum continuous power dissipation of the anode in Watts. The entire family of tubes can be used as oscillators, modulators, and amplifiers. Specifications The 4-1000A is a relatively large glass tube with an overall height of 9.25 inches and a diameter of 5 inches. It is designed to operate with its plate (anode) at an orange-red color due to the "getter" being a zirconium compound on the anode structure which requires a great deal of heat to be effective. The cathode is a directly heated, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thorium
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided. All known thorium isotopes are unstable. The most stable isotope, 232Th, has a half-life of 14.05 billion years, or about the age of the universe; it decays very slowly via alpha decay, starting a decay chain named the thorium series that ends at stable 208 Pb. On Earth, thorium and uranium are the only significantly radioactive elements that still occur naturally in large quantities as primordial elements. Thorium is estimated to be over three times as abundant as uranium in the Earth's crust, and is chiefly refined from monazite sands as a by-product of extracti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ampere
The ampere (, ; symbol: A), often shortened to amp,SI supports only the use of symbols and deprecates the use of abbreviations for units. is the unit of electric current in the International System of Units (SI). One ampere is equal to electrons worth of charge moving past a point in a second. It is named after French mathematician and physicist André-Marie Ampère (1775–1836), considered the father of electromagnetism along with Danish physicist Hans Christian Ørsted. As of the 2019 redefinition of the SI base units, the ampere is defined by fixing the elementary charge to be exactly C ( coulomb), which means an ampere is an electrical current equivalent to elementary charges moving every seconds or elementary charges moving in a second. Prior to the redefinition the ampere was defined as the current that would need to be passed through 2 parallel wires 1 metre apart to produce a magnetic force of newtons per metre. The earlier CGS system had two definitio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class C Amplifier
In electronics, power amplifier classes are letter symbols applied to different power amplifier types. The class gives a broad indication of an amplifier's characteristics and performance. The classes are related to the time period that the active amplifier device is passing current, expressed as a fraction of the period of a signal waveform applied to the input. A class A amplifier is conducting through all the period of the signal; Class B only for one-half the input period, class C for much less than half the input period. A Class D amplifier operates its output device in a switching manner; the fraction of the time that the device is conducting is adjusted so a pulse-width modulation output is obtained from the stage. Additional letter classes are defined for special-purpose amplifiers, with additional active elements or particular power supply improvements; sometimes a new letter symbol is used by a manufacturer to promote its proprietary design. Power amplifier classes Powe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modulator
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains information to be transmitted. For example, the modulation signal might be an audio signal representing sound from a microphone, a video signal representing moving images from a video camera, or a digital signal representing a sequence of binary digits, a bitstream from a computer. The carrier is higher in frequency than the modulation signal. In radio communication the modulated carrier is transmitted through space as a radio wave to a radio receiver. Another purpose is to transmit multiple channels of information through a single communication medium, using frequency-division multiplexing (FDM). For example in cable television which uses FDM, many carrier signals, each modulated with a different television channel, are transported through a sing ... [...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 W6UF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amperex Electronic
Amperex Electronic Corporation was a manufacturer of vacuum tubes and semiconductors.Knight (2007) Brooklyn, New York Originally located at 79 Washington Street in Brooklyn, New York, Amperex was a long-established manufacturer of transmitting tubes when they were acquired by the Dutch firm, Philips, (known more widely as Norelco in the US), around 1955. Philips continued to improve and enlarge the tube plant in New York, but also used the Amperex name to distribute their new line of Dutch-made miniature tubes, (12AX7, 12AU7, 12AT7) to feed the booming U.S. hi-fi market. Classic hi-fi brands such as Marantz, Fisher, and H. H. Scott, Inc., used these tubes. Amperex also produced the 6DJ8, 6922 and 7308 frame grid tubes. Developed by Amperex in 1958 when transistors were beginning to supplant tubes and originally developed for video and radar use, the 6DJ8 also excelled in audio amplifiers needing its high transconductance, and it still has a niche market among audiophiles. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrifugal Fan
A centrifugal fan is a mechanical device for moving air or other gases in a direction at an angle to the incoming fluid. Centrifugal fans often contain a ducted housing to direct outgoing air in a specific direction or across a heat sink; such a fan is also called a blower, blower fan, or squirrel-cage fan (because it looks like a hamster wheel). Tiny ones used in computers are sometimes called biscuit blowers. These fans move air from the rotating inlet of the fan to an outlet. They are typically used in ducted applications to either draw air through ductwork/heat exchanger, or push air through similar. impellers. Compared to standard axial fans, they can provide similar air movement from a smaller fan package, and overcome higher resistance in air streams. Centrifugal fans use the kinetic energy of the impellers to move the air stream, which in turn moves against the resistance caused by ducts, dampers and other components. Centrifugal fans displace air radially, changing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chassis
A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart of a motor vehicle, on which the body is mounted; if the running gear such as wheels and transmission, and sometimes even the driver's seat, are included, then the assembly is described as a rolling chassis. Examples of use Vehicles In the case of vehicles, the term ''rolling chassis'' means the frame plus the "running gear" like engine, transmission, drive shaft, differential and suspension. An underbody (sometimes referred to as "coachwork"), which is usually not necessary for integrity of the structure, is built on the chassis to complete the vehicle. For commercial vehicles, a rolling chassis consists of an assembly of all the essential parts of a truck without the body to be ready for operation on the road. A car chassis wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Sink
A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allowing regulation of the device's temperature. In computers, heat sinks are used to cool CPUs, GPUs, and some chipsets and RAM modules. Heat sinks are used with high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light-emitting diodes (LEDs), where the heat dissipation ability of the component itself is insufficient to moderate its temperature. A heat sink is designed to maximize its surface area in contact with the cooling medium surrounding it, such as the air. Air velocity, choice of material, protrusion design and surface treatment are factors that affect the performance of a heat sink. Heat sink attachment methods and thermal interface materials also affect the die temperature of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
