1.
Anti-aircraft warfare
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Anti-aircraft warfare or counter-air defence is defined by NATO as all measures designed to nullify or reduce the effectiveness of hostile air action. They include ground-and air-based weapon systems, associated sensor systems, command and control arrangements and it may be used to protect naval, ground, and air forces in any location. However, for most countries the main effort has tended to be homeland defence, NATO refers to airborne air defence as counter-air and naval air defence as anti-aircraft warfare. Missile defence is an extension of air defence as are initiatives to adapt air defence to the task of intercepting any projectile in flight, a surface-based air defence capability can also be deployed offensively to deny the use of airspace to an opponent. Until the 1950s, guns firing ballistic munitions ranging from 20 mm to 150 mm were the weapons, guided missiles then became dominant. The term air defence was probably first used by Britain when Air Defence of Great Britain was created as a Royal Air Force command in 1925. However, arrangements in the UK were also called anti-aircraft, abbreviated as AA, after the First World War it was sometimes prefixed by Light or Heavy to classify a type of gun or unit. Nicknames for anti-aircraft guns include AA, AAA or triple-A, an abbreviation of anti-aircraft artillery, ack-ack, NATO defines anti-aircraft warfare as measures taken to defend a maritime force against attacks by airborne weapons launched from aircraft, ships, submarines and land-based sites. In some armies the term All-Arms Air Defence is used for air defence by nonspecialist troops, other terms from the late 20th century include GBAD with related terms SHORAD and MANPADS. Anti-aircraft missiles are variously called surface-to-air missile, abbreviated and pronounced SAM, non-English terms for air defence include the German FlaK, whence English flak, and the Russian term Protivovozdushnaya oborona, a literal translation of anti-air defence, abbreviated as PVO. In Russian the AA systems are called zenitnye systems, in French, air defence is called DCA. The maximum distance at which a gun or missile can engage an aircraft is an important figure, however, many different definitions are used but unless the same definition is used, performance of different guns or missiles cannot be compared. For AA guns only the part of the trajectory can be usefully used. By the late 1930s the British definition was that height at which an approaching target at 400 mph can be engaged for 20 seconds before the gun reaches 70 degrees elevation. However, effective ceiling for heavy AA guns was affected by nonballistic factors, The maximum running time of the fuse, the capability of fire control instruments to determine target height at long range. The essence of air defence is to detect aircraft and destroy them. The critical issue is to hit a target moving in three-dimensional space, Air defence evolution covered the areas of sensors and technical fire control, weapons, and command and control. At the start of the 20th century these were very primitive or non-existent
2.
Battery (electricity)
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An electric battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, smartphones, and electric cars. When a battery is supplying power, its positive terminal is the cathode. The terminal marked negative is the source of electrons that when connected to a circuit will flow. It is the movement of ions within the battery which allows current to flow out of the battery to perform work. Historically the term specifically referred to a device composed of multiple cells. Primary batteries are used once and discarded, the materials are irreversibly changed during discharge. Common examples are the battery used for flashlights and a multitude of portable electronic devices. Secondary batteries can be discharged and recharged multiple times using mains power from a wall socket, examples include the lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics such as laptops and smartphones. According to a 2005 estimate, the battery industry generates US$48 billion in sales each year. Batteries have much lower energy than common fuels such as gasoline. This is somewhat offset by the efficiency of electric motors in producing mechanical work. The usage of battery to describe a group of electrical devices dates to Benjamin Franklin, alessandro Volta built and described the first electrochemical battery, the voltaic pile, in 1800. This was a stack of copper and zinc plates, separated by brine-soaked paper disks, Volta did not understand that the voltage was due to chemical reactions. Although early batteries were of value for experimental purposes, in practice their voltages fluctuated. It consisted of a pot filled with a copper sulfate solution, in which was immersed an unglazed earthenware container filled with sulfuric acid. These wet cells used liquid electrolytes, which were prone to leakage and spillage if not handled correctly, many used glass jars to hold their components, which made them fragile and potentially dangerous. These characteristics made wet cells unsuitable for portable appliances, near the end of the nineteenth century, the invention of dry cell batteries, which replaced the liquid electrolyte with a paste, made portable electrical devices practical. Batteries convert chemical energy directly to electrical energy, a battery consists of some number of voltaic cells
3.
Lithium battery
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Lithium batteries are batteries that have lithium as an anode. These types of batteries are also referred to as lithium-metal batteries and they stand apart from other batteries in their high charge density and high cost per unit. The term lithium battery refers to a family of different lithium-metal chemistries, comprising many types of cathodes and electrolytes, the battery requires from 0.15 to 0.3 kg of lithium per kWh. The most common type of lithium cell used in consumer applications uses metallic lithium as anode and manganese dioxide as cathode, another type of lithium cell having a large energy density is the lithium-thionyl chloride cell. The cell contains a mixture of thionyl chloride and lithium tetrachloroaluminate. A porous carbon material serves as a current collector which receives electrons from the external circuit. Lithium-thionyl chloride batteries are well suited to extremely low-current applications where long life is necessary, the liquid organic electrolyte is a solution of an ion-forming inorganic lithium compound in a mixture of a high-permittivity solvent and a low-viscosity solvent. Lithium batteries find application in many long-life, critical devices, such as pacemakers and these devices use specialized lithium-iodide batteries designed to last 15 or more years. But for other, less critical applications such as in toys, in such cases, an expensive lithium battery may not be cost-effective. Lithium batteries can be used in place of ordinary alkaline cells in many devices, such as clocks, although they are more costly, lithium cells will provide much longer life, thereby minimizing battery replacement. However, attention must be given to the voltage developed by the lithium cells before using them as a drop-in replacement in devices that normally use ordinary zinc cells. Lithium batteries also prove valuable in oceanographic applications, while lithium battery packs are considerably more expensive than standard oceanographic packs, they hold up to three times the capacity of alkaline packs. The high cost of servicing remote oceanographic instrumentation often justifies this higher cost and they are available in many shapes and sizes, with a common variety being the 3 volt coin type manganese variety, typically 20 mm in diameter and 1. 6–4 mm thick. The heavy electrical demands of many of these devices make lithium batteries a particularly attractive option, in particular, lithium batteries can easily support the brief, heavy current demands of devices such as digital cameras, and they maintain a higher voltage for a longer period than alkaline cells. Lithium primary batteries account for 28% of all battery sales in Japan. In the EU only 0. 5% of all battery sales including secondary types are lithium primaries, the computer industrys drive to increase battery capacity can test the limits of sensitive components such as the membrane separator, a polyethylene or polypropylene film that is only 20-25 µm thick. The energy density of lithium batteries has more than doubled since they were introduced in 1991, when the battery is made to contain more material, the separator can undergo stress. Lithium batteries can provide extremely high currents and can discharge very rapidly when short-circuited, although this is useful in applications where high currents are required, a too-rapid discharge of a lithium battery can result in overheating of the battery, rupture, and even explosion
4.
Television
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Television or TV is a telecommunication medium used for transmitting moving images in monochrome, or in color, and in two or three dimensions and sound. The term can refer to a set, a television program. Television is a medium for entertainment, education, news, politics, gossip. Television became available in experimental forms in the late 1920s. After World War II, a form of black-and-white TV broadcasting became popular in the United States and Britain, and television sets became commonplace in homes, businesses. During the 1950s, television was the medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in the US, for many reasons, the storage of television and video programming now occurs on the cloud. At the end of the first decade of the 2000s, digital television transmissions greatly increased in popularity, another development was the move from standard-definition television to high-definition television, which provides a resolution that is substantially higher. HDTV may be transmitted in various formats, 1080p, 1080i, in 2013, 79% of the worlds households owned a television set. Most TV sets sold in the 2000s were flat-panel, mainly LEDs, major manufacturers announced the discontinuation of CRT, DLP, plasma, and even fluorescent-backlit LCDs by the mid-2010s. In the near future, LEDs are gradually expected to be replaced by OLEDs, also, major manufacturers have announced that they will increasingly produce smart TVs in the mid-2010s. Smart TVs with integrated Internet and Web 2.0 functions became the dominant form of television by the late 2010s, Television signals were initially distributed only as terrestrial television using high-powered radio-frequency transmitters to broadcast the signal to individual television receivers. Alternatively television signals are distributed by cable or optical fiber, satellite systems and. Until the early 2000s, these were transmitted as analog signals, a standard television set is composed of multiple internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device which lacks a tuner is correctly called a video monitor rather than a television, the word television comes from Ancient Greek τῆλε, meaning far, and Latin visio, meaning sight. The Anglicised version of the term is first attested in 1907 and it was. formed in English or borrowed from French télévision. In the 19th century and early 20th century, other. proposals for the name of a technology for sending pictures over distance were telephote. The abbreviation TV is from 1948, the use of the term to mean a television set dates from 1941
5.
Lithium-ion battery
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A lithium-ion battery or Li-ion battery is a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. Li-ion batteries use an intercalated lithium compound as one electrode material, the electrolyte, which allows for ionic movement, and the two electrodes are the constituent components of a lithium-ion battery cell. Lithium-ion batteries are common in home electronics and they are one of the most popular types of rechargeable batteries for portable electronics, with a high energy density, tiny memory effect and low self-discharge. Beyond consumer electronics, LIBs are also growing in popularity for military, battery electric vehicle, for example, lithium-ion batteries are becoming a common replacement for the lead–acid batteries that have been used historically for golf carts and utility vehicles. Chemistry, performance, cost and safety characteristics vary across LIB types, handheld electronics mostly use LIBs based on lithium cobalt oxide, which offers high energy density, but presents safety risks, especially when damaged. Lithium iron phosphate, lithium ion manganese oxide battery and lithium nickel manganese cobalt oxide offer lower energy density, such batteries are widely used for electric tools, medical equipment and other roles. NMC in particular is a contender for automotive applications. Lithium nickel cobalt aluminum oxide and lithium titanate are specialty designs aimed at particular niche roles, the newer lithium–sulfur batteries promise the highest performance-to-weight ratio. Lithium-ion batteries can pose unique safety hazards since they contain a flammable electrolyte, an expert notes If a battery cell is charged too quickly, it can cause a short circuit, leading to explosions and fires. Because of these risks, testing standards are more stringent than those for acid-electrolyte batteries, there have been battery-related recalls by some companies, including the 2016 Samsung Note 7 recall for battery fires. This article covers just the topics and general principles of lithium-ion batteries. Nearly all facets have elements that are impacted by currently very active development or research, a cell is a basic electrochemical unit that contains the basic components, such as electrodes, separator, and electrolyte. In the case of cells, this is the single cylindrical, prismatic or pouch unit. In this regard, the simplest battery is a cell with perhaps a small electronic circuit for protection. In many cases, distinguishing between cell and battery is not important, however, this should be done when dealing with specific applications, for example, battery electric vehicles, where battery may indicate a high voltage system of 400 V, and not a single cell. The term module is used as an intermediate topology, with the understanding that a battery pack is made of modules. In electrochemistry, the anode is the electrode where oxidation is taking place in the battery, i. e. electrons get free, however, this happens on opposite electrodes during charge vs. discharge. Historically, for lithium cells, which started as single use discharge cells and this is true on discharge, but with a rechargeable system, the negative electrode chemically becomes the cathode while charging
6.
Battery nomenclature
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Standard battery nomenclature describes portable dry cell batteries that have physical dimensions and electrical characteristics interchangeable between manufacturers. The long history of dry cells means that many different manufacturer-specific and national standards were used to designate sizes. Technical standards for battery sizes and types are set by organizations such as International Electrotechnical Commission. Popular sizes are referred to by old standard or manufacturer designations. The complete nomenclature for the battery will fully specify the size, chemistry, terminal arrangements, the same physically interchangeable cell size may have widely different characteristics, physical interchangeability is not the sole factor in substitution of batteries. National standards for dry cell batteries have been developed by ANSI, JIS, British national standards, civilian, commercial, government and military standards all exist. Two of the most prevalent standards currently in use are the IEC60086 series, both standards give dimensions, standard performance characteristics, and safety information. Modern standards contain both systematic names for types that give information on the composition and approximate size of the cells. The International Electrotechnical Commission was established in France in 1906 and co-ordinates development of standards for a range of electrical products. The IEC maintains two committees, TC21 established in 1933 for rechargeable batteries, and TC35 established in 1948 for primary batteries, the current designation system was adopted in 1992. Battery types are designated with a sequence indicating number of cells, cell chemistry, cell shape, dimensions. Certain cell designations from earlier revisions of the standard have been retained, the first IEC standards for battery sizes were issued in 1957. Since 1992, International standard IEC60086 defines an alphanumeric coding system for batteries, British standard 397 for primary batteries was withdrawn and replaced by the IEC standard in 1996. Standardization of batteries in the United States started in 1919, when the US National Bureau of Standards published recommended test procedures, the first American Standards Association standard C18 appeared in 1928. It listed cell sizes using a code, roughly in order of size from smallest to larger types. The only numerical designation was the 6-inch tall No.6 cell, the 1934 edition of the C18 standard expanded the nomenclature system to include series and parallel arrays of cells. In 1954, mercury batteries were included in the standard, the 1959 edition identified types suitable for use with transistor radios. In 1967, NEMA took over responsibility for development from the National Bureau of Standards, the 12th edition of C18 began to be harmonized with the IEC standard
7.
Battery holder
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A battery holder is one or more compartments or chambers for holding a battery. For dry cells, the holder must also make contact with the battery terminals. For wet cells, cables are connected to the battery terminals. Battery holders may have a lid to retain and protect the batteries, or may be sealed to prevent damage to circuitry, coiled spring wire or flat tabs that press against the battery terminals are the two most common methods of making the electrical connection inside a holder. External connections on battery holders are made by contacts with pins, surface mount feet, solder lugs. Where the battery is expected to last over the life of the product, no holder is necessary, in the late 1800s patents were issued for consumer products like flashlights, patent no.617592 dated March 1898 is for an early metal flashlight that accepted D batteries. Some early 1900s battery holders were often no more than a box with copper contacts. By the 1920s, battery holders used twin metal clips to hold the battery in place while making electrical contact. Patent no.1439429 was granted in Dec.1922 for an assembly with two spring arm clips, a switch and a lamp assembly on the end of connected wires. The introduction of polypropylene in the 1950s and miniature batteries by Eveready allowed for the use of small plastic battery holders and these are still common in toys, decorations, and lighted or blinking items. In 1957, electric wrist watches gained popularity with the public, Battery holders developed in parallel with batteries over time, as battery package sizes shrunk so did the holders. In the 1980s, the first circuit board mounting lithium coin cell battery holders appeared in the form of patent no.4487820 by the battery holder manufacturer MPD, the electronics industry now uses many surface mounted lithium battery holders or sockets. CR2/3A, CR1/2AA and CR123A batteries began in camera applications, but expanded into new markets like alarm systems, hand held computers, design of the battery holder requires knowledge of how and where the larger product will be used. Human factors to be considered include ease of exchange, age range. These elements must be taken into account for a design to be successful and are part of the design process, a designer must select between a battery holder molded into the product case or made as a separate part. For many products regulations and product safety standards affect the battery holder selection, most current battery holders are made with polypropylene or nylon bodies rated for 80-100 °C. Battery contacts are the most important part of the design and require serious consideration, since batteries are nickel-plated, it is recommended the contacts be nickel-plated to prevent galvanic corrosion between dissimilar metals. Battery contacts may be fixed contacts, flexible contacts, or some combination of the two, fixed contacts are inexpensive but prone to loss of electrical connection
8.
Nine-volt battery
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The nine-volt battery, or 9-volt battery, in its most common form was introduced for the early transistor radios. It has a rectangular shape with rounded edges and a polarized snap connector at the top. This type is used in walkie talkies, clocks and smoke detectors. Mercury-oxide batteries of this format, once common, have not been manufactured in many due to their mercury content. Designations for this format include NEDA1604 and IEC 6F22 or MN1604 6LR61, the size, regardless of chemistry, is commonly designated PP3 - a designation originally reserved solely for carbon-zinc - or in some countries, E or E-block. Most nine-volt alkaline batteries are constructed of six individual 1. 5V LR61 cells enclosed in a wrapper and these cells are slightly smaller than LR8D425 AAAA cells and can be used in their place for some devices, even though they are 3.5 mm shorter. Carbon-zinc types are made with six cells in a stack. Primary lithium types are made with 3 cells in series, in 2007, 9-volt batteries accounted for 4% of alkaline primary battery sales in the US. In Switzerland in 2008, 9-volt batteries totalled 2% of primary battery sales, other nine-volt batteries of different sizes exist, such as the British Ever Ready PP series and certain lantern batteries. The battery has both terminals in a connector on one end. The smaller circular terminal is positive, and the hexagonal or octagonal terminal is the negative contact. The connectors on the battery are the same as on the connector itself, the same snap-style connector is used on other battery types in the Power Pack series. Battery polarization is normally obvious since mechanical connection is only possible in one configuration. A problem with this style of connector is that it is easy to connect two batteries together in a short circuit, which quickly discharges both batteries, generating heat and possibly a fire. Because of this hazard, 9-volt batteries should be kept in the original packaging until they are going to be used, an advantage is that several nine-volt batteries can be connected to each other in series to provide higher voltages. Early transistorized radios and other equipment needed a suitable miniature battery. Early transistor radios required a 22 1⁄2 volt battery, fortunately a suitable miniature battery was already marketed for hearing aids. The PP3 appeared when portable transistorised radio receivers became common, and is called a transistor battery by some manufacturers
9.
Alkaline battery
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Alkaline batteries are a type of primary battery dependent upon the reaction between zinc and manganese dioxide. Another type of batteries are secondary rechargeable alkaline battery, which allows reuse of specially designed cells. Compared with zinc-carbon batteries of the Leclanché or zinc chloride types, alkaline batteries have an energy density and longer shelf-life. The alkaline battery gets its name because it has an electrolyte of potassium hydroxide. Other battery systems also use alkaline electrolytes, but they use different active materials for the electrodes, Alkaline batteries account for 80% of manufactured batteries in the US and over 10 billion individual units produced worldwide. In Japan alkaline batteries account for 46% of all battery sales. In Switzerland alkaline batteries account for 68%, in the UK 60%, Alkaline batteries are used in many household items such as MP3 players, CD players, digital cameras, pagers, toys, lights, and radios, to name a few. Batteries with alkaline electrolyte were first developed by Waldemar Jungner in 1899, on October 9,1957, Urry, Karl Kordesch, and P. A. Marsal filed US patent for the alkaline battery and it was granted in 1960 and was assigned to the Union Carbide Corporation. When introduced in the late 1960s, alkaline batteries contained a small amount of mercury amalgam to control side reactions at the zinc anode. With mercury content reduced by law and improvements in the purity and consistency of materials, in an alkaline battery, the negative electrode is zinc and the positive electrode is manganese dioxide. The alkaline electrolyte of potassium hydroxide is not part of the reaction, only the zinc, the alkaline electrolyte of potassium hydroxide remains, as there are equal amounts of OH− consumed and produced. An alkaline cell can provide three and five times capacity. The capacity of a battery is strongly dependent on the load. An AA-sized alkaline battery might have a capacity of 3000 mAh at low drain, but at a load of 1 ampere, which is common for digital cameras. The voltage of the battery declines steadily during use, so the usable capacity depends on the cut-off voltage of the application. Unlike Leclanche cells, the alkaline cell delivers about as much capacity on intermittent or continuous light loads, on a heavy load, capacity is reduced on continuous discharge compared with intermittent discharge, but the reduction is less than for Leclanche cells. The nominal voltage of an alkaline cell as established by manufacturer standards is 1.5 V
10.
Voltage
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Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential energy between two points per unit electric charge. The voltage between two points is equal to the work done per unit of charge against an electric field to move the test charge between two points. This is measured in units of volts, voltage can be caused by static electric fields, by electric current through a magnetic field, by time-varying magnetic fields, or some combination of these three. A voltmeter can be used to measure the voltage between two points in a system, often a reference potential such as the ground of the system is used as one of the points. A voltage may represent either a source of energy or lost, used, given two points in space, x A and x B, voltage is the difference in electric potential between those two points. Electric potential must be distinguished from electric energy by noting that the potential is a per-unit-charge quantity. Like mechanical potential energy, the zero of electric potential can be chosen at any point, so the difference in potential, i. e. the voltage, is the quantity which is physically meaningful. The voltage between point A to point B is equal to the work which would have to be done, per unit charge, against or by the electric field to move the charge from A to B. The voltage between the two ends of a path is the energy required to move a small electric charge along that path. Mathematically this is expressed as the integral of the electric field. In the general case, both an electric field and a dynamic electromagnetic field must be included in determining the voltage between two points. Historically this quantity has also called tension and pressure. Pressure is now obsolete but tension is used, for example within the phrase high tension which is commonly used in thermionic valve based electronics. Voltage is defined so that negatively charged objects are pulled towards higher voltages, therefore, the conventional current in a wire or resistor always flows from higher voltage to lower voltage. Current can flow from lower voltage to higher voltage, but only when a source of energy is present to push it against the electric field. This is the case within any electric power source, for example, inside a battery, chemical reactions provide the energy needed for ion current to flow from the negative to the positive terminal. The electric field is not the only factor determining charge flow in a material, the electric potential of a material is not even a well defined quantity, since it varies on the subatomic scale. A more convenient definition of voltage can be found instead in the concept of Fermi level, in this case the voltage between two bodies is the thermodynamic work required to move a unit of charge between them
