1.
Coaxial cable
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Coaxial cable, or coax, is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. Many coaxial cables also have an outer sheath or jacket. The term coaxial comes from the conductor and the outer shield sharing a geometric axis. Coaxial cable was invented by English engineer and mathematician Oliver Heaviside, Coaxial cable is used as a transmission line for radio frequency signals. Its applications include feedlines connecting radio transmitters and receivers with their antennas, computer network connections, digital audio and this allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other types of transmission lines. Coaxial cable also provides protection of the signal from external electromagnetic interference, the cable is protected by an outer insulating jacket. Normally, the shield is kept at ground potential and a signal carrying voltage is applied to the center conductor, the advantage of coaxial design is that electric and magnetic fields are restricted to the dielectric with little leakage outside the shield. Conversely, electric and magnetic fields outside the cable are largely kept from interfering with signals inside the cable, larger diameter cables and cables with multiple shields have less leakage. Common applications of coaxial cable include video and CATV distribution, RF and microwave transmission, the characteristic impedance of the cable is determined by the dielectric constant of the inner insulator and the radii of the inner and outer conductors. A controlled cable characteristic impedance is important because the source and load impedance should be matched to ensure maximum power transfer, other important properties of coaxial cable include attenuation as a function of frequency, voltage handling capability, and shield quality. Coaxial cable design choices affect physical size, frequency performance, attenuation, power handling capabilities, flexibility, strength, the inner conductor might be solid or stranded, stranded is more flexible. To get better performance, the inner conductor may be silver-plated. Copper-plated steel wire is used as an inner conductor for cable used in the cable TV industry. The insulator surrounding the conductor may be solid plastic, a foam plastic. The properties of control some electrical properties of the cable. A common choice is a solid polyethylene insulator, used in lower-loss cables, solid Teflon is also used as an insulator. Some coaxial lines use air and have spacers to keep the conductor from touching the shield. Many conventional coaxial cables use braided copper wire forming the shield and this allows the cable to be flexible, but it also means there are gaps in the shield layer, and the inner dimension of the shield varies slightly because the braid cannot be flat
2.
Ethernet
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Ethernet /ˈiːθərnɛt/ is a family of computer networking technologies commonly used in local area networks, metropolitan area networks and wide area networks. It was commercially introduced in 1980 and first standardized in 1983 as IEEE802.3, over time, Ethernet has largely replaced competing wired LAN technologies such as token ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses coaxial cable as a medium, while the newer Ethernet variants use twisted pair. Over the course of its history, Ethernet data transfer rates have increased from the original 2.94 megabits per second to the latest 100 gigabits per second. The Ethernet standards comprise several wiring and signaling variants of the OSI physical layer in use with Ethernet, systems communicating over Ethernet divide a stream of data into shorter pieces called frames. As per the OSI model, Ethernet provides services up to, since its commercial release, Ethernet has retained a good degree of backward compatibility. Features such as the 48-bit MAC address and Ethernet frame format have influenced other networking protocols, the primary alternative for some uses of contemporary LANs is Wi-Fi, a wireless protocol standardized as IEEE802.11. Ethernet was developed at Xerox PARC between 1973 and 1974 and it was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation. In 1975, Xerox filed a patent application listing Metcalfe, David Boggs, Chuck Thacker, in 1976, after the system was deployed at PARC, Metcalfe and Boggs published a seminal paper. Metcalfe left Xerox in June 1979 to form 3Com and he convinced Digital Equipment Corporation, Intel, and Xerox to work together to promote Ethernet as a standard. The so-called DIX standard, for Digital/Intel/Xerox, specified 10 Mbit/s Ethernet, with 48-bit destination and source addresses and it was published on September 30,1980 as The Ethernet, A Local Area Network. Data Link Layer and Physical Layer Specifications, version 2 was published in November,1982 and defines what has become known as Ethernet II. Formal standardization efforts proceeded at the time and resulted in the publication of IEEE802.3 on June 23,1983. Ethernet initially competed with two largely proprietary systems, Token Ring and Token Bus, in the process, 3Com became a major company. 3Com shipped its first 10 Mbit/s Ethernet 3C100 NIC in March 1981, an Ethernet adapter card for the IBM PC was released in 1982, and, by 1985, 3Com had sold 100,000. Parallel port based Ethernet adapters were produced for a time, with drivers for DOS, by the early 1990s, Ethernet became so prevalent that it was a must-have feature for modern computers, and Ethernet ports began to appear on some PCs and most workstations. This process was sped up with the introduction of 10BASE-T and its relatively small modular connector. Since then, Ethernet technology has evolved to meet new bandwidth, in addition to computers, Ethernet is now used to interconnect appliances and other personal devices
3.
Bayonet mount
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To couple the two parts, the pin on the male are aligned with the slot on the female and the two pushed together. Once the pins reach the bottom of the slot, one or both parts are rotated so that the pin slides along the arm of the L until it reaches the serif. The spring then pushes the male connector up into the serif to keep the pin locked into place, a practised user can connect them quickly and, unlike screw connectors, they are not subject to cross-threading. To disconnect, the two parts are pushed together to move the pin out of the serif while twisting in the opposite direction than for connecting, the strength of the joint comes from the strength of the pins and the L slots, and the spring. It is possible to push down the connector and rotate it, but not far enough to engage and lock, it will stay in place temporarily, Bayonet electrical connectors are used in the same applications where other connectors are used, to transmit either power or signals. Bayonet connections can be faster than screw connections, and more securely than push-fit connections. They may be used to two cables, or to connect a cable to a connector on the panel of a piece of equipment. The coupling system is made of two bayonet ramps machined on the external side of the receptacle connector and 2 stainless steel studs mounted inside the plug connector’s coupling nut. Several classes of electrical connectors, including audio, video. Examples include BNC, C, and ST connectors, the first documented use of this type of fitting may be by Al-Jazari in the 13th century, who used it to mount candles into his candle-clocks. This type of fitting was later used for soldiers who needed to mount bayonets to the ends of their rifles. The standard size is B22d-2, often referred to in the context of lighting as simply BC, older installations in some other countries, including France and Greece use this base. Examples of three-pin bulbs are found in street lamps and fireglow bulbs in some older models of electric radiative heater. Older railway carriages in the UK also made use of a 3 pin bulb base to discourage theft, Bayonet cap bulbs are also very common worldwide in applications where vibration may loosen screw-mount bulbs, such as automotive lighting and other small indicators, and in many flashlights. In many other countries the Edison screw base is used for lighting, newer bulbs use a wedge base which can be inserted either way with no issues. Some special-purpose bulbs, such as infra-red, have 3 pins 120 degrees apart to prevent them being used in any, Bayonet bases or caps are often abbreviated to BA, often with a number after. The number refers to the diameter of the base, bA15, a 15 mm base, can also be referred to as SBC standing for small bayonet cap. The lower-case letter s or d specifies whether the bulb has single or double contacts, while G actually indicates bi-pin, those listed above have a twist-lock, but with parallel pins from the end instead of opposing pins on the side
4.
Video
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Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video systems vary greatly in the resolution of the display and refresh rate, video can be carried on a variety of media, including radio broadcast, tapes, DVDs, computer files etc. Video was originally exclusively a live technology, charles Ginsburg led an Ampex research team developing one of the first practical video tape recorder. In 1951 the first video tape recorder captured live images from television cameras by converting the electrical impulses. Video recorders were sold for $50,000 in 1956, however, prices gradually dropped over the years, in 1971, Sony began selling videocassette recorder decks and tapes into the consumer market. The use of techniques in video created digital video, which allowed higher quality and, eventually. After the invention of the DVD in 1997 and Blu-ray Disc in 2006, sales of videotape, the advent of digital broadcasting and the subsequent digital television transition is in the process of relegating analog video to the status of a legacy technology in most parts of the world. PAL standards and SECAM specify 25 frame/s, while NTSC standards specify 29.97 frames, film is shot at the slower frame rate of 24 frames per second, which slightly complicates the process of transferring a cinematic motion picture to video. The minimum frame rate to achieve a comfortable illusion of an image is about sixteen frames per second. Video can be interlaced or progressive, analog display devices reproduce each frame in the same way, effectively doubling the frame rate as far as perceptible overall flicker is concerned. NTSC, PAL and SECAM are interlaced formats, abbreviated video resolution specifications often include an i to indicate interlacing. For example, PAL video format is specified as 576i50, where 576 indicates the total number of horizontal scan lines, i indicates interlacing. In progressive scan systems, each refresh period updates all scan lines in each frame in sequence, when displaying a natively progressive broadcast or recorded signal, the result is optimum spatial resolution of both the stationary and moving parts of the image. Deinterlacing cannot, however, produce video quality that is equivalent to true progressive scan source material, aspect ratio describes the dimensions of video screens and video picture elements. All popular video formats are rectilinear, and so can be described by a ratio between width and height, the screen aspect ratio of a traditional television screen is 4,3, or about 1.33,1. High definition televisions use a ratio of 16,9. The aspect ratio of a full 35 mm film frame with soundtrack is 1.375,1. Therefore, a 720 by 480 pixel NTSC DV image displayes with the 4,3 aspect ratio if the pixels are thin, the popularity of viewing video on mobile phones has led to the growth of vertical video
5.
Radio
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When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form, Radio systems need a transmitter to modulate some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation. Radio systems also need an antenna to convert electric currents into radio waves, an antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected, the electromagnetic wave is intercepted by a tuned receiving antenna. Radio frequencies occupy the range from a 3 kHz to 300 GHz, a radio communication system sends signals by radio. The term radio is derived from the Latin word radius, meaning spoke of a wheel, beam of light, however, this invention would not be widely adopted. The switch to radio in place of wireless took place slowly and unevenly in the English-speaking world, the United States Navy would also play a role. Although its translation of the 1906 Berlin Convention used the terms wireless telegraph and wireless telegram, the term started to become preferred by the general public in the 1920s with the introduction of broadcasting. Radio systems used for communication have the following elements, with more than 100 years of development, each process is implemented by a wide range of methods, specialised for different communications purposes. Each system contains a transmitter, This consists of a source of electrical energy, the transmitter contains a system to modulate some property of the energy produced to impress a signal on it. This modulation might be as simple as turning the energy on and off, or altering more subtle such as amplitude, frequency, phase. Amplitude modulation of a carrier wave works by varying the strength of the signal in proportion to the information being sent. For example, changes in the strength can be used to reflect the sounds to be reproduced by a speaker. It was the used for the first audio radio transmissions. Frequency modulation varies the frequency of the carrier, the instantaneous frequency of the carrier is directly proportional to the instantaneous value of the input signal. FM has the capture effect whereby a receiver only receives the strongest signal, Digital data can be sent by shifting the carriers frequency among a set of discrete values, a technique known as frequency-shift keying. FM is commonly used at Very high frequency radio frequencies for high-fidelity broadcasts of music, analog TV sound is also broadcast using FM. Angle modulation alters the phase of the carrier wave to transmit a signal
6.
Electronic test equipment
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Electronic test equipment is used to create signals and capture responses from electronic devices under test. In this way, the operation of the DUT can be proven or faults in the device can be traced. Use of electronic test equipment is essential to any work on electronics systems. ATE often includes many of instruments in real and simulated forms. Generally, more advanced test gear is necessary when developing circuits, designing a test system’s switching configuration requires an understanding of the signals to be switched and the tests to be performed, as well as the switching hardware form factors available. The following items are used for measurement of voltages, currents. Voltmeter Ohmmeter Ammeter, e. g. Galvanometer or Milliameter Multimeter e. g. VOM or DMM RLC Meter e. g and these systems are widely employed for incoming inspection, quality assurance, and production testing of electronic devices and subassemblies. The General Purpose Interface Bus is an IEEE-488 standard parallel interface used for attaching sensors, GPIB is a digital 8-bit parallel communications interface capable of achieving data transfers of more than 8 Mbytes/s. It allows daisy-chaining up to 14 instruments to a system using a 24-pin connector. It is one of the most common I/O interfaces present in instruments and is designed specifically for instrument control applications, the IEEE-488 specifications standardized this bus and defined its electrical, mechanical, and functional specifications, while also defining its basic software communication rules. GPIB works best for applications in industrial settings that require a connection for instrument control. The original GPIB standard was developed in the late 1960s by Hewlett-Packard to connect, the introduction of digital controllers and programmable test equipment created a need for a standard, high-speed interface for communication between instruments and controllers from various vendors. This standard was revised in 1978 and 1990. The IEEE488.2 specification includes the Standard Commands for Programmable Instrumentation, SCPI ensures compatibility and configurability among these instruments. The IEEE-488 bus has long been popular because it is simple to use and takes advantage of a selection of programmable instruments. Large systems, however, have the limitations, Driver fanout capacity limits the system to 14 devices plus a controller. Cable length limits the distance to two meters per device or 20 meters total, whichever is less. This imposes transmission problems on systems spread out in a room or on systems that require remote measurements, primary addresses limit the system to 30 devices with primary addresses
7.
Consumer electronics
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Consumer electronics or home electronics are electronic or digital equipment intended for everyday use, typically in private homes. Consumer electronics include devices used for entertainment, communications, and home-office activities, in British English, they are often called brown goods by producers and sellers, to distinguish them from white goods such as washing machines and refrigerators. Radio broadcasting in the early 20th century brought the first major consumer product, later products included telephones, personal computers, MP3 players, audio equipment, televisions and calculators. In the 2010s, consumer electronics stores often sell GPS, automotive electronics, video game consoles, electronic instruments, karaoke machines, digital cameras. Stores also sell digital cameras, camcorders, cell phones, some consumer electronics stores, such as Best Buy have also begun selling office and baby furniture. Consumer electronics stores may be bricks and mortar retail stores, online stores. The CEA estimated the value of 2015 consumer electronics sales at US$220 billion, for its first fifty years the phonograph turntable did not use electronics, the needle and soundhorn were purely mechanical technologies. However, in the 1920s radio broadcasting became the basis of production of radio receivers. The vacuum tubes that had made radios practical were used with record players as well, television was soon invented, but remained insignificant in the consumer market until the 1950s. The transistor, invented in 1947 by Bell Laboratories, led to significant research in the field of semiconductors in the early 1950s. The transistors advantages revolutionized that industry along with other electronics, by 1959 Fairchild Semiconductor had introduced the first planar transistor from which come the origins of Moores Law. Integrated circuits followed when manufacturers built circuits on a substrate using electrical connections between circuits within the chip itself. One overriding characteristic of consumer products is the trend of ever-falling prices. This is driven by gains in manufacturing efficiency and automation, lower costs as manufacturing has moved to lower-wage countries. Semiconductor components benefit from Moores Law, a principle which states that, for a given price. While consumer electronics continues in its trend of convergence, combining elements of many products, there is an ever increasing need to keep product information updated and comparable, for the consumer to make an informed choice. Style, price, specification, and performance are all relevant, there is a gradual shift towards e-commerce web-storefronts. Many products include Internet connectivity using technologies such as Wi-Fi, Bluetooth, products not traditionally associated with computer use now provide options to connect to the Internet or to a computer using a home network to provide access to digital content
8.
RCA connector
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An RCA connector, sometimes called a phono connector or Cinch connector, is a type of electrical connector commonly used to carry audio and video signals. The connectors are sometimes casually referred to as A/V jacks. The name RCA derives from the Radio Corporation of America, which introduced the design by the early 1940s for internal connection of the pickup to the chassis in home radio-phonograph consoles. It was originally a low-cost, simple design, intended only for mating, refinement came with later designs, although they remained compatible. However, quarter-inch phone connectors are common in professional audio. The connections plug is called an RCA plug or phono plug, the name phono plug is sometimes confused with a phone plug which may refer to a quarter-inch phone plug – Tip/Sleeve or Tip/Ring/Sleeve connector – or to a 4P4C connector used for a telephone. In the most normal use, cables have a plug on each end, consisting of a central male connector. The ring is often segmented for flexibility, devices mount the socket, consisting of a central hole with a ring of metal around it. The ring is smaller in diameter and longer than the ring on the plug. The jack has an area between the outer and inner rings which is filled with an insulator, typically plastic. Its use as a connector for video signals is extremely common. RCA connectors and cable are commonly used to carry S/PDIF-formatted digital audio. Connections are made by pushing the cables plug into the jack on the device. Continuous noise can occur if the plug partially falls out of the jack, breaking ground connection, some variants of the plug, especially cheaper versions, also give very poor grip and contact between the ground sheaths due to their lack of flexibility. They are often color-coded, yellow for composite video, red for the audio channel. This trio of jacks can be found on the back of almost all audio, one or more sets are often found on TV sets to facilitate connection of camcorders, other portable video sources and video game consoles. Varying cable quality means that a cheap line-level audio cable might not successfully transfer component video, cables should meet the S/PDIF specification as defined by the international standard IEC 60958-3 for assured performance. The male plug has a pin which is 3.175 mm in diameter
9.
Network interface controller
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A network interface controller is a computer hardware component that connects a computer to a computer network. Early network interface controllers were commonly implemented on expansion cards that plugged into a computer bus, the low cost and ubiquity of the Ethernet standard means that most newer computers have a network interface built into the motherboard. The network controller implements the electronic circuitry required to communicate using a physical layer and data link layer standard such as Ethernet, Fibre Channel. The NIC allows computers to communicate over a network, either by using cables or wirelessly. Although other network technologies exist, IEEE802 networks including the Ethernet variants have achieved near-ubiquity since the mid-1990s, newer server motherboards may even have dual network interfaces built-in. The Ethernet capabilities are integrated into the motherboard chipset or implemented via a low-cost dedicated Ethernet chip. A separate network card is not required unless additional interfaces are needed or some type of network is used. The NIC may use one or more of the techniques to indicate the availability of packets to transfer. Interrupt-driven I/O is where the peripheral alerts the CPU that it is ready to transfer data, also, NICs may use one or more of the following techniques to transfer packet data, Programmed input/output is where the CPU moves the data to or from the NIC to memory. Direct memory access is where some other device other than the CPU assumes control of the bus to move data to or from the NIC to memory. This removes load from the CPU but requires more logic on the card, in addition, a packet buffer on the NIC may not be required and latency can be reduced. There are two types of DMA, third-party DMA in which a DMA controller other than the NIC performs transfers, an Ethernet network controller typically has an 8P8C socket where the network cable is connected. Older NICs also supplied BNC, or AUI connections, a few LEDs inform the user of whether the network is active, and whether or not data transmission occurs. Ethernet network controllers typically support 10 Mbit/s Ethernet,100 Mbit/s Ethernet, such controllers are designated as 10/100/1000, meaning that they can support a notional maximum transfer rate of 10,100 or 1000 Mbit/s. 10 Gigabit Ethernet NICs are also available, and, as of November 2014, are beginning to be available on computer motherboards, multiqueue NICs provide multiple transmit and receive queues, allowing packets received by the NIC to be assigned to one of its receive queues. The hardware-based distribution of the interrupts, described above, is referred to as receive-side scaling, purely software implementations also exist, such as the receive packet steering and receive flow steering. Examples of such implementations are the RFS and Intel Flow Director, with multiqueue NICs, additional performance improvements can be achieved by distributing outgoing traffic among different transmit queues. By assigning different transmit queues to different CPUs/cores, various operating systems internal contentions can be avoided and those NICs support, Accessing local and remote memory without involving the remote CPU
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