title: Telephone content: – their diaphragm vibrated a coil of wire in the field of a permanent magnet or the coil vibrated the diaphragm. The sound-powered dynamic variants survived in small numbers through the 20th century in military and maritime applications, where its ability to create its own electrical power was crucial. Most, however, used the Edison/Berliner carbon transmitter, which was much louder than the other kinds, even though it required an induction coil which was an impedance matching transformer to make it compatible with the impedance of the line. The Edison patents kept the Bell monopoly viable into the 20th century, by


title: Telephone content: which time the network was more important than the instrument. Early telephones were locally powered, using either a dynamic transmitter or by the powering of a transmitter with a local battery. One of the jobs of outside plant personnel was to visit each telephone periodically to inspect the battery. During the 20th century, telephones powered from the telephone exchange over the same wires that carried the voice signals became common. Early telephones used a single wire for the subscriber's line, with ground return used to complete the circuit (as used in telegraphs). The earliest dynamic telephones also had only one


title: Telephone content: port opening for sound, with the user alternately listening and speaking (or rather, shouting) into the same hole. Sometimes the instruments were operated in pairs at each end, making conversation more convenient but also more expensive. At first, the benefits of a telephone exchange were not exploited. Instead telephones were leased in pairs to a subscriber, who had to arrange for a telegraph contractor to construct a line between them, for example between a home and a shop. Users who wanted the ability to speak to several different locations would need to obtain and set up three or four pairs


title: Telephone content: of telephones. Western Union, already using telegraph exchanges, quickly extended the principle to its telephones in New York City and San Francisco, and Bell was not slow in appreciating the potential. Signalling began in an appropriately primitive manner. The user alerted the other end, or the exchange operator, by whistling into the transmitter. Exchange operation soon resulted in telephones being equipped with a bell in a ringer box, first operated over a second wire, and later over the same wire, but with a condenser (capacitor) in series with the bell coil to allow the AC ringer signal through while still


title: Telephone content: blocking DC (keeping the phone "on hook"). Telephones connected to the earliest Strowger switch automatic exchanges had seven wires, one for the knife switch, one for each telegraph key, one for the bell, one for the push-button and two for speaking. Large wall telephones in the early 20th century usually incorporated the bell, and separate bell boxes for desk phones dwindled away in the middle of the century. Rural and other telephones that were not on a common battery exchange had a magneto hand-cranked generator to produce a high voltage alternating signal to ring the bells of other telephones on


title: Telephone content: the line and to alert the operator. Some local farming communities that were not connected to the main networks set up barbed wire telephone lines that exploited the existing system of field fences to transmit the signal. In the 1890s a new smaller style of telephone was introduced, packaged in three parts. The transmitter stood on a stand, known as a "candlestick" for its shape. When not in use, the receiver hung on a hook with a switch in it, known as a "switchhook". Previous telephones required the user to operate a separate switch to connect either the voice or


title: Telephone content: the bell. With the new kind, the user was less likely to leave the phone "off the hook". In phones connected to magneto exchanges, the bell, induction coil, battery and magneto were in a separate bell box or "ringer box". In phones connected to common battery exchanges, the ringer box was installed under a desk, or other out of the way place, since it did not need a battery or magneto. Cradle designs were also used at this time, having a handle with the receiver and transmitter attached, now called a handset, separate from the cradle base that housed the


title: Telephone content: magneto crank and other parts. They were larger than the "candlestick" and more popular. Disadvantages of single wire operation such as crosstalk and hum from nearby AC power wires had already led to the use of twisted pairs and, for long distance telephones, four-wire circuits. Users at the beginning of the 20th century did not place long distance calls from their own telephones but made an appointment to use a special soundproofed long distance telephone booth furnished with the latest technology. What turned out to be the most popular and longest lasting physical style of telephone was introduced in the


title: Telephone content: early 20th century, including Bell's 202-type desk set. A carbon granule transmitter and electromagnetic receiver were united in a single molded plastic handle, which when not in use sat in a cradle in the base unit. The circuit diagram of the model 202 shows the direct connection of the transmitter to the line, while the receiver was induction coupled. In local battery configurations, when the local loop was too long to provide sufficient current from the exchange, the transmitter was powered by a local battery and inductively coupled, while the receiver was included in the local loop. The coupling transformer


title: Telephone content: and the ringer were mounted in a separate enclosure, called the subscriber set. The dial switch in the base interrupted the line current by repeatedly but very briefly disconnecting the line 1 to 10 times for each digit, and the hook switch (in the center of the circuit diagram) disconnected the line and the transmitter battery while the handset was on the cradle. In the 1930s, telephone sets were developed that combined the bell and induction coil with the desk set, obviating a separate ringer box. The rotary dial becoming commonplace in the 1930s in many areas enabled customer-dialed service,


title: Telephone content: but some magneto systems remained even into the 1960s. After World War II, the telephone networks saw rapid expansion and more efficient telephone sets, such as the model 500 telephone in the United States, were developed that permitted larger local networks centered around central offices. A breakthrough new technology was the introduction of Touch-Tone signaling using push-button telephones by American Telephone & Telegraph Company (AT&T) in 1963. The invention of the transistor in 1947 dramatically changed the technology used in telephone systems and in the long-distance transmission networks. With the development of electronic switching systems in the 1960s, telephony gradually


title: Telephone content: evolved towards digital telephony which improved the capacity, quality, and cost of the network. The development of digital data communications method, such as the protocols used for the Internet, it became possible to digitize voice and transmit it as real-time data across computer networks, giving rise to the field of Internet Protocol (IP) telephony, also known as voice over Internet Protocol (VoIP), a term that reflects the methodology memorably. VoIP has proven to be a disruptive technology that is rapidly replacing traditional telephone network infrastructure. As of January 2005, up to 10% of telephone subscribers in Japan and South Korea


title: Telephone content: have switched to this digital telephone service. A January 2005 Newsweek article suggested that Internet telephony may be "the next big thing." As of 2006 many VoIP companies offer service to consumers and businesses. From a customer perspective, IP telephony uses a high-bandwidth Internet connection and specialized customer premises equipment to transmit telephone calls via the Internet, or any modern private data network. The customer equipment may be an analog telephone adapter (ATA) which interfaces a conventional analog telephone to the IP networking equipment, or it may be an IP Phone that has the networking and interface technology built into


title: Telephone content: the desk-top set and provides the traditional, familiar parts of a telephone, the handset, the dial or keypad, and a ringer in a package that usually resembles a standard telephone set. In addition, many computer software vendors and telephony operators provide softphone application software that emulates a telephone by use of an attached microphone and audio headset, or loud speaker. Despite the new features and conveniences of IP telephones, some may have notable disadvantages compared to traditional telephones. Unless the IP telephone's components are backed up with an uninterruptible power supply or other emergency power source, the phone ceases to


title: Telephone content: function during a power outage as can occur during an emergency or disaster when the phone is most needed. Traditional phones connected to the older PSTN network do not experience that problem since they are powered by the telephone company's battery supply, which will continue to function even if there is a prolonged power outage. Another problem in Internet-based services is the lack of a fixed physical location, impacting the provisioning of emergency services such as police, fire or ambulance, should someone call for them. Unless the registered user updates the IP phone's physical address location after moving to a


title: Telephone content: new residence, emergency services can be, and have been, dispatched to the wrong location. Graphic symbols used to designate telephone service or phone-related information in print, signage, and other media include ℡ (U+2121), ☎ (U+260E), ☏ (U+260F), ✆ (U+2706) and ⌕ (U+2315). In 2002, only 10% of the world’s population used cell phones and by 2005 that percentage had risen to 46%. By the end of 2009, there were a total of nearly 6 billion mobile and fixed-line telephone subscribers worldwide. This included 1.26 billion fixed-line subscribers and 4.6 billion mobile subscribers. Telephone A telephone, or phone, is a telecommunications


title: Transistor content: Transistor A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits. The transistor is the fundamental building block of modern electronic devices,


title: Transistor content: and is ubiquitous in modern electronic systems. Julius Edgar Lilienfeld patented a field-effect transistor in 1926 but it was not possible to actually construct a working device at that time. The first practically implemented device was a point-contact transistor invented in 1947 by American physicists John Bardeen, Walter Brattain, and William Shockley. The transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things. The transistor is on the list of IEEE milestones in electronics, and Bardeen, Brattain, and Shockley shared the 1956 Nobel Prize in Physics for their achievement.


title: Transistor content: Most transistors are made from very pure silicon or germanium, but certain other semiconductor materials can also be used. A transistor may have only one kind of charge carrier, in a field effect transistor, or may have two kinds of charge carriers in bipolar junction transistor devices. Compared with the vacuum tube, transistors are generally smaller, and require less power to operate. Certain vacuum tubes have advantages over transistors at very high operating frequencies or high operating voltages. Many types of transistors are made to standardized specifications by multiple manufacturers. The thermionic triode, a vacuum tube invented in 1907, enabled


title: Transistor content: amplified radio technology and long-distance telephony. The triode, however, was a fragile device that consumed a substantial amount of power. In 1909 physicist William Eccles discovered the crystal diode oscillator. German physicist Julius Edgar Lilienfeld filed a patent for a field-effect transistor (FET) in Canada in 1925, which was intended to be a solid-state replacement for the triode. Lilienfeld also filed identical patents in the United States in 1926 and 1928. However, Lilienfeld did not publish any research articles about his devices nor did his patents cite any specific examples of a working prototype. Because the production of high-quality semiconductor


title: Transistor content: materials was still decades away, Lilienfeld's solid-state amplifier ideas would not have found practical use in the 1920s and 1930s, even if such a device had been built. In 1934, German inventor Oskar Heil patented a similar device in Europe. From November 17, 1947, to December 23, 1947, John Bardeen and Walter Brattain at AT&T's Bell Labs in Murray Hill, New Jersey of the United States performed experiments and observed that when two gold point contacts were applied to a crystal of germanium, a signal was produced with the output power greater than the input. Solid State Physics Group leader


title: Transistor content: William Shockley saw the potential in this, and over the next few months worked to greatly expand the knowledge of semiconductors. The term "transistor" was coined by John R. Pierce as a contraction of the term "transresistance". According to Lillian Hoddeson and Vicki Daitch, authors of a biography of John Bardeen, Shockley had proposed that Bell Labs' first patent for a transistor should be based on the field-effect and that he be named as the inventor. Having unearthed Lilienfeld’s patents that went into obscurity years earlier, lawyers at Bell Labs advised against Shockley's proposal because the idea of a field-effect


title: Transistor content: transistor that used an electric field as a "grid" was not new. Instead, what Bardeen, Brattain, and Shockley invented in 1947 was the first point-contact transistor. In acknowledgement of this accomplishment, Shockley, Bardeen, and Brattain were jointly awarded the 1956 Nobel Prize in Physics "for their researches on semiconductors and their discovery of the transistor effect". In 1948, the point-contact transistor was independently invented by German physicists Herbert Mataré and Heinrich Welker while working at the "Compagnie des Freins et Signaux", a Westinghouse subsidiary located in Paris. Mataré had previous experience in developing crystal rectifiers from silicon and germanium in


title: Transistor content: the German radar effort during World War II. Using this knowledge, he began researching the phenomenon of "interference" in 1947. By June 1948, witnessing currents flowing through point-contacts, Mataré produced consistent results using samples of germanium produced by Welker, similar to what Bardeen and Brattain had accomplished earlier in December 1947. Realizing that Bell Labs' scientists had already invented the transistor before them, the company rushed to get its "transistron" into production for amplified use in France's telephone network. The first bipolar junction transistors were invented by Bell Labs' William Shockley, which applied for patent (2,569,347) on June 26, 1948.


title: Transistor content: On April 12, 1950, Bell Labs chemists Gordon Teal and Morgan Sparks had successfully produced a working bipolar NPN junction amplifying germanium transistor. Bell Labs had announced the discovery of this new "sandwich" transistor in a press release on July 4, 1951. The first high-frequency transistor was the surface-barrier germanium transistor developed by Philco in 1953, capable of operating up to . These were made by etching depressions into an N-type germanium base from both sides with jets of Indium(III) sulfate until it was a few ten-thousandths of an inch thick. Indium electroplated into the depressions formed the collector and


title: Transistor content: emitter. The first "prototype" pocket transistor radio was shown by INTERMETALL (a company founded by Herbert Mataré in 1952) at the "Internationale Funkausstellung Düsseldorf" between August 29, 1953 and September 9, 1953. The first "production" pocket transistor radio was the Regency TR-1, released in October 1954. Produced as a joint venture between the Regency Division of Industrial Development Engineering Associates, I.D.E.A. and Texas Instruments of Dallas Texas, the TR-1 was manufactured in Indianapolis, Indiana. It was a near pocket-sized radio featuring 4 transistors and one germanium diode. The industrial design was outsourced to the Chicago firm of Painter, Teague and


title: Transistor content: Petertil. It was initially released in one of four different colours: black, bone white, red, and gray. Other colours were to shortly follow. The first "production" all-transistor car radio was developed by Chrysler and Philco corporations and it was announced in the April 28th 1955 edition of the Wall Street Journal. Chrysler had made the all-transistor car radio, Mopar model 914HR, available as an option starting in fall 1955 for its new line of 1956 Chrysler and Imperial cars which first hit the dealership showroom floors on October 21, 1955. The first working silicon transistor was developed at Bell Labs


title: Transistor content: on January 26, 1954 by Morris Tanenbaum. The first commercial silicon transistor was produced by Texas Instruments in 1954. This was the work of Gordon Teal, an expert in growing crystals of high purity, who had previously worked at Bell Labs. The first MOSFET actually built was by Kahng and Atalla at Bell Labs in 1960. The transistor is the key active component in practically all modern electronics. Many consider it to be one of the greatest inventions of the 20th century. Its importance in today's society rests on its ability to be mass-produced using a highly automated process (semiconductor


title: Transistor content: device fabrication) that achieves astonishingly low per-transistor costs. The invention of the first transistor at Bell Labs was named an IEEE Milestone in 2009. Although several companies each produce over a billion individually packaged (known as "discrete") transistors every year, the vast majority of transistors are now produced in integrated circuits (often shortened to "IC", "microchips" or simply "chips"), along with diodes, resistors, capacitors and other electronic components, to produce complete electronic circuits. A logic gate consists of up to about twenty transistors whereas an advanced microprocessor, as of 2009, can use as many as 3 billion transistors (MOSFETs). "About


title: Transistor content: 60 million transistors were built in 2002… for [each] man, woman, and child on Earth." The transistor's low cost, flexibility, and reliability have made it a ubiquitous device. Transistorized mechatronic circuits have replaced electromechanical devices in controlling appliances and machinery. It is often easier and cheaper to use a standard microcontroller and write a computer program to carry out a control function than to design an equivalent mechanical system to control that same function. The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much


title: Transistor content: larger signal at another pair of terminals. This property is called gain. It can produce a stronger output signal, a voltage or current, which is proportional to a weaker input signal; that is, it can act as an amplifier. Alternatively, the transistor can be used to turn current on or off in a circuit as an electrically controlled switch, where the amount of current is determined by other circuit elements. There are two types of transistors, which have slight differences in how they are used in a circuit. A "bipolar transistor" has terminals labeled base, collector, and emitter. A small


title: Transistor content: current at the base terminal (that is, flowing between the base and the emitter) can control or switch a much larger current between the collector and emitter terminals. For a "field-effect transistor", the terminals are labeled gate, source, and drain, and a voltage at the gate can control a current between source and drain. The image represents a typical bipolar transistor in a circuit. Charge will flow between emitter and collector terminals depending on the current in the base. Because internally the base and emitter connections behave like a semiconductor diode, a voltage drop develops between base and emitter while


title: Transistor content: the base current exists. The amount of this voltage depends on the material the transistor is made from, and is referred to as "V". Transistors are commonly used in digital circuits as electronic switches which can be either in an "on" or "off" state, both for high-power applications such as switched-mode power supplies and for low-power applications such as logic gates. Important parameters for this application include the current switched, the voltage handled, and the switching speed, characterised by the rise and fall times. In a grounded-emitter transistor circuit, such as the light-switch circuit shown, as the base voltage rises,


title: Transistor content: the emitter and collector currents rise exponentially. The collector voltage drops because of reduced resistance from collector to emitter. If the voltage difference between the collector and emitter were zero (or near zero), the collector current would be limited only by the load resistance (light bulb) and the supply voltage. This is called "saturation" because current is flowing from collector to emitter freely. When saturated, the switch is said to be "on". Providing sufficient base drive current is a key problem in the use of bipolar transistors as switches. The transistor provides current gain, allowing a relatively large current in


title: Transistor content: the collector to be switched by a much smaller current into the base terminal. The ratio of these currents varies depending on the type of transistor, and even for a particular type, varies depending on the collector current. In the example light-switch circuit shown, the resistor is chosen to provide enough base current to ensure the transistor will be saturated. In a switching circuit, the idea is to simulate, as near as possible, the ideal switch having the properties of open circuit when off, short circuit when on, and an instantaneous transition between the two states. Parameters are chosen such


title: Transistor content: that the "off" output is limited to leakage currents too small to affect connected circuitry; the resistance of the transistor in the "on" state is too small to affect circuitry; and the transition between the two states is fast enough not to have a detrimental effect. The common-emitter amplifier is designed so that a small change in voltage ("V") changes the small current through the base of the transistor; the transistor's current amplification combined with the properties of the circuit means that small swings in "V" produce large changes in "V". Various configurations of single transistor amplifier are possible, with


title: Transistor content: some providing current gain, some voltage gain, and some both. From mobile phones to televisions, vast numbers of products include amplifiers for sound reproduction, radio transmission, and signal processing. The first discrete-transistor audio amplifiers barely supplied a few hundred milliwatts, but power and audio fidelity gradually increased as better transistors became available and amplifier architecture evolved. Modern transistor audio amplifiers of up to a few hundred watts are common and relatively inexpensive. Before transistors were developed, vacuum (electron) tubes (or in the UK "thermionic valves" or just "valves") were the main active components in electronic equipment. The key advantages that


title: Transistor content: have allowed transistors to replace vacuum tubes in most applications are Transistors have the following limitations: Transistors are categorized by Hence, a particular transistor may be described as "silicon, surface-mount, BJT, n–p–n, low-power, high-frequency switch". A popular way to remember which symbol represents which type of transistor is to look at the arrow and how it is arranged. Within an NPN transistor symbol, the arrow will Not Point iN. Conversely, within the PNP symbol you see that the arrow Points iN Proudly. Bipolar transistors are so named because they conduct by using both majority and minority carriers. The bipolar junction


title: Transistor content: transistor, the first type of transistor to be mass-produced, is a combination of two junction diodes, and is formed of either a thin layer of p-type semiconductor sandwiched between two n-type semiconductors (an n–p–n transistor), or a thin layer of n-type semiconductor sandwiched between two p-type semiconductors (a p–n–p transistor). This construction produces two p–n junctions: a base–emitter junction and a base–collector junction, separated by a thin region of semiconductor known as the base region (two junction diodes wired together without sharing an intervening semiconducting region will not make a transistor). BJTs have three terminals, corresponding to the three layers


title: Transistor content: of semiconductor—an "emitter", a "base", and a "collector". They are useful in amplifiers because the currents at the emitter and collector are controllable by a relatively small base current. In an n–p–n transistor operating in the active region, the emitter–base junction is forward biased (electrons and holes recombine at the junction), and the base-collector junction is reverse biased (electrons and holes are formed at, and move away from the junction), and electrons are injected into the base region. Because the base is narrow, most of these electrons will diffuse into the reverse-biased base–collector junction and be swept into the collector;


title: Transistor content: perhaps one-hundredth of the electrons will recombine in the base, which is the dominant mechanism in the base current. As well, as the base is lightly doped (in comparison to the emitter and collector regions), recombination rates are low, permitting more carriers to diffuse across the base region. By controlling the number of electrons that can leave the base, the number of electrons entering the collector can be controlled. Collector current is approximately β (common-emitter current gain) times the base current. It is typically greater than 100 for small-signal transistors but can be smaller in transistors designed for high-power applications.


title: Transistor content: Unlike the field-effect transistor (see below), the BJT is a low-input-impedance device. Also, as the base–emitter voltage ("V") is increased the base–emitter current and hence the collector–emitter current ("I") increase exponentially according to the Shockley diode model and the Ebers-Moll model. Because of this exponential relationship, the BJT has a higher transconductance than the FET. Bipolar transistors can be made to conduct by exposure to light, because absorption of photons in the base region generates a photocurrent that acts as a base current; the collector current is approximately β times the photocurrent. Devices designed for this purpose have a transparent


title: Transistor content: window in the package and are called phototransistors. The "field-effect transistor", sometimes called a "unipolar transistor", uses either electrons (in "n-channel FET") or holes (in "p-channel FET") for conduction. The four terminals of the FET are named "source", "gate", "drain", and "body" ("substrate"). On most FETs, the body is connected to the source inside the package, and this will be assumed for the following description. In a FET, the drain-to-source current flows via a conducting channel that connects the "source" region to the "drain" region. The conductivity is varied by the electric field that is produced when a voltage is


title: Transistor content: applied between the gate and source terminals; hence the current flowing between the drain and source is controlled by the voltage applied between the gate and source. As the gate–source voltage ("V") is increased, the drain–source current ("I") increases exponentially for "V" below threshold, and then at a roughly quadratic rate ("I" ∝ ("V" − "V")) (where "V" is the threshold voltage at which drain current begins) in the "space-charge-limited" region above threshold. A quadratic behavior is not observed in modern devices, for example, at the 65 nm technology node. For low noise at narrow bandwidth the higher input resistance


title: Transistor content: of the FET is advantageous. FETs are divided into two families: "junction FET" (JFET) and "insulated gate FET" (IGFET). The IGFET is more commonly known as a "metal–oxide–semiconductor FET" (MOSFET), reflecting its original construction from layers of metal (the gate), oxide (the insulation), and semiconductor. Unlike IGFETs, the JFET gate forms a p–n diode with the channel which lies between the source and drain. Functionally, this makes the n-channel JFET the solid-state equivalent of the vacuum tube triode which, similarly, forms a diode between its grid and cathode. Also, both devices operate in the "depletion mode", they both have a


title: Transistor content: high input impedance, and they both conduct current under the control of an input voltage. Metal–semiconductor FETs (MESFETs) are JFETs in which the reverse biased p–n junction is replaced by a metal–semiconductor junction. These, and the HEMTs (high-electron-mobility transistors, or HFETs), in which a two-dimensional electron gas with very high carrier mobility is used for charge transport, are especially suitable for use at very high frequencies (microwave frequencies; several GHz). FETs are further divided into "depletion-mode" and "enhancement-mode" types, depending on whether the channel is turned on or off with zero gate-to-source voltage. For enhancement mode, the channel is off


title: Transistor content: at zero bias, and a gate potential can "enhance" the conduction. For the depletion mode, the channel is on at zero bias, and a gate potential (of the opposite polarity) can "deplete" the channel, reducing conduction. For either mode, a more positive gate voltage corresponds to a higher current for n-channel devices and a lower current for p-channel devices. Nearly all JFETs are depletion-mode because the diode junctions would forward bias and conduct if they were enhancement-mode devices; most IGFETs are enhancement-mode types. The bipolar junction transistor (BJT) was the most commonly used transistor in the 1960s and 70s. Even


title: Transistor content: after MOSFETs became widely available, the BJT remained the transistor of choice for many analog circuits such as amplifiers because of their greater linearity and ease of manufacture. In integrated circuits, the desirable properties of MOSFETs allowed them to capture nearly all market share for digital circuits. Discrete MOSFETs can be applied in transistor applications, including analog circuits, voltage regulators, amplifiers, power transmitters and motor drivers. The types of some transistors can be parsed from the part number. There are three major semiconductor naming standards; in each the alphanumeric prefix provides clues to type of the device. The "JIS-C-7012" specification


title: Transistor content: for transistor part numbers starts with "2S", e.g. 2SD965, but sometimes the "2S" prefix is not marked on the package – a 2SD965 might only be marked "D965"; a 2SC1815 might be listed by a supplier as simply "C1815". This series sometimes has suffixes (such as "R", "O", "BL", standing for "red", "orange", "blue", etc.) to denote variants, such as tighter "h" (gain) groupings. The Pro Electron standard, the European Electronic Component Manufacturers Association part numbering scheme, begins with two letters: the first gives the semiconductor type (A for germanium, B for silicon, and C for materials like GaAs); the


title: Transistor content: second letter denotes the intended use (A for diode, C for general-purpose transistor, etc.). A 3-digit sequence number (or one letter then two digits, for industrial types) follows. With early devices this indicated the case type. Suffixes may be used, with a letter (e.g. "C" often means high "h", such as in: BC549C) or other codes may follow to show gain (e.g. BC327-25) or voltage rating (e.g. BUK854-800A). The more common prefixes are: The JEDEC "EIA370" transistor device numbers usually start with "2N", indicating a three-terminal device (dual-gate field-effect transistors are four-terminal devices, so begin with 3N), then a 2,


title: Transistor content: 3 or 4-digit sequential number with no significance as to device properties (although early devices with low numbers tend to be germanium). For example, 2N3055 is a silicon n–p–n power transistor, 2N1301 is a p–n–p germanium switching transistor. A letter suffix (such as "A") is sometimes used to indicate a newer variant, but rarely gain groupings. Manufacturers of devices may have their own proprietary numbering system, for example CK722. Since devices are second-sourced, a manufacturer's prefix (like "MPF" in MPF102, which originally would denote a Motorola FET) now is an unreliable indicator of who made the device. Some proprietary naming


title: Transistor content: schemes adopt parts of other naming schemes, for example a PN2222A is a (possibly Fairchild Semiconductor) 2N2222A in a plastic case (but a PN108 is a plastic version of a BC108, not a 2N108, while the PN100 is unrelated to other xx100 devices). Military part numbers sometimes are assigned their own codes, such as the British Military CV Naming System. Manufacturers buying large numbers of similar parts may have them supplied with "house numbers", identifying a particular purchasing specification and not necessarily a device with a standardized registered number. For example, an HP part 1854,0053 is a (JEDEC) 2N2218 transistor


title: Transistor content: which is also assigned the CV number: CV7763 With so many independent naming schemes, and the abbreviation of part numbers when printed on the devices, ambiguity sometimes occurs. For example, two different devices may be marked "J176" (one the J176 low-power JFET, the other the higher-powered MOSFET 2SJ176). As older "through-hole" transistors are given surface-mount packaged counterparts, they tend to be assigned many different part numbers because manufacturers have their own systems to cope with the variety in pinout arrangements and options for dual or matched n–p–n + p–n–p devices in one pack. So even when the original device (such


title: Transistor content: as a 2N3904) may have been assigned by a standards authority, and well known by engineers over the years, the new versions are far from standardized in their naming. The first BJTs were made from germanium (Ge). Silicon (Si) types currently predominate but certain advanced microwave and high-performance versions now employ the "compound semiconductor" material gallium arsenide (GaAs) and the "semiconductor alloy" silicon germanium (SiGe). Single element semiconductor material (Ge and Si) is described as "elemental". Rough parameters for the most common semiconductor materials used to make transistors are given in the adjacent table; these parameters will vary with increase


title: Transistor content: in temperature, electric field, impurity level, strain, and sundry other factors. The "junction forward voltage" is the voltage applied to the emitter–base junction of a BJT in order to make the base conduct a specified current. The current increases exponentially as the junction forward voltage is increased. The values given in the table are typical for a current of 1 mA (the same values apply to semiconductor diodes). The lower the junction forward voltage the better, as this means that less power is required to "drive" the transistor. The junction forward voltage for a given current decreases with increase in


title: Transistor content: temperature. For a typical silicon junction the change is −2.1 mV/°C. In some circuits special compensating elements (sensistors) must be used to compensate for such changes. The density of mobile carriers in the channel of a MOSFET is a function of the electric field forming the channel and of various other phenomena such as the impurity level in the channel. Some impurities, called dopants, are introduced deliberately in making a MOSFET, to control the MOSFET electrical behavior. The "electron mobility" and "hole mobility" columns show the average speed that electrons and holes diffuse through the semiconductor material with an electric


title: Transistor content: field of 1 volt per meter applied across the material. In general, the higher the electron mobility the faster the transistor can operate. The table indicates that Ge is a better material than Si in this respect. However, Ge has four major shortcomings compared to silicon and gallium arsenide: Because the electron mobility is higher than the hole mobility for all semiconductor materials, a given bipolar n–p–n transistor tends to be swifter than an equivalent p–n–p transistor. GaAs has the highest electron mobility of the three semiconductors. It is for this reason that GaAs is used in high-frequency applications. A


title: Transistor content: relatively recent FET development, the "high-electron-mobility transistor" (HEMT), has a heterostructure (junction between different semiconductor materials) of aluminium gallium arsenide (AlGaAs)-gallium arsenide (GaAs) which has twice the electron mobility of a GaAs-metal barrier junction. Because of their high speed and low noise, HEMTs are used in satellite receivers working at frequencies around 12 GHz. HEMTs based on gallium nitride and aluminium gallium nitride (AlGaN/GaN HEMTs) provide a still higher electron mobility and are being developed for various applications. Max. junction temperature values represent a cross section taken from various manufacturers' data sheets. This temperature should not be exceeded or the


title: Transistor content: transistor may be damaged. Al–Si junction refers to the high-speed (aluminum–silicon) metal–semiconductor barrier diode, commonly known as a Schottky diode. This is included in the table because some silicon power IGFETs have a "parasitic" reverse Schottky diode formed between the source and drain as part of the fabrication process. This diode can be a nuisance, but sometimes it is used in the circuit. Discrete transistors can be individually packaged transistors or unpackaged transistor chips (dice). Transistors come in many different semiconductor packages (see image). The two main categories are "through-hole" (or "leaded"), and "surface-mount", also known as "surface-mount device" (SMD).


title: Transistor content: The "ball grid array" (BGA) is the latest surface-mount package (currently only for large integrated circuits). It has solder "balls" on the underside in place of leads. Because they are smaller and have shorter interconnections, SMDs have better high-frequency characteristics but lower power rating. Transistor packages are made of glass, metal, ceramic, or plastic. The package often dictates the power rating and frequency characteristics. Power transistors have larger packages that can be clamped to heat sinks for enhanced cooling. Additionally, most power transistors have the collector or drain physically connected to the metal enclosure. At the other extreme, some surface-mount


title: Transistor content: "microwave" transistors are as small as grains of sand. Often a given transistor type is available in several packages. Transistor packages are mainly standardized, but the assignment of a transistor's functions to the terminals is not: other transistor types can assign other functions to the package's terminals. Even for the same transistor type the terminal assignment can vary (normally indicated by a suffix letter to the part number, q.e. BC212L and BC212K). Nowadays most transistors come in a wide range of SMT packages, in comparison the list of available through-hole packages is relatively small, here is a short list of


title: Transistor content: the most common through-hole transistors packages in alphabetical order: ATV, E-line, MRT, HRT, SC-43, SC-72, TO-3, TO-18, TO-39, TO-92, TO-126, TO220, TO247, TO251, TO262, ZTX851. Unpackaged transistor chips (die) may be assembled into hybrid devices. The IBM SLT module of the 1960s is one example of such a hybrid circuit module using glass passivated transistor (and diode) die. Other packaging techniques for discrete transistors as chips include Direct Chip Attach (DCA) and Chip On Board (COB). Researchers have made several kinds of flexible transistors, including organic field-effect transistors. Flexible transistors are useful in some kinds of flexible displays and other


title: Transistor content: flexible electronics. Transistor A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits. The transistor is the fundamental building block of modern


title: "The Sound of Music" content: A production ran at the Ópera-Citi theater in Buenos Aires, Argentina in 2011. The cast included Laura Conforte as Maria and Diego Ramos as Captain Von Trapp. A Spanish national tour began in November 2011 at the Auditorio de Tenerife in Santa Cruz de Tenerife in the Canary Islands. The tour visited 29 Spanish cities, spending one year in Madrid's Gran Vía at the Teatro Coliseum, and one season at the Tívoli Theatre in Barcelona. It was directed by Jaime Azpilicueta and starred Silvia Luchetti as Maria and Carlos J. Benito as Captain Von Trapp. A production was mounted at


title: "Treaty of Versailles" content: theories were given credence by the fact that when Germany surrendered in November 1918, its armies were still on French and Belgian territory. Furthermore, on the Eastern Front, Germany had already won the war against Russia and concluded the Treaty of Brest-Litovsk. In the West, Germany had seemed to have come close to winning the war with the Spring Offensive earlier in 1918. Its failure was blamed on strikes in the arms industry at a critical moment of the offensive, leaving soldiers with an inadequate supply of materiel. The strikes were regarded by nationalists as having been instigated by traitors,


title: Tin content: stable isotopes, with atomic masses of 112, 114 through 120, 122 and 124, the greatest number of any element. Of these, the most abundant are Sn (almost a third of all tin), Sn, and Sn, while the least abundant is Sn. The isotopes with even mass numbers have no nuclear spin, while those with odd have a spin of +1/2. Tin, with its three common isotopes Sn, Sn and Sn, is among the easiest elements to detect and analyze by NMR spectroscopy, and its chemical shifts are referenced against . This large number of stable isotopes is thought to be


title: Torch content: Torch A torch is a stick with combustible material at one end, which is ignited and used as a light source. Torches have been used throughout history, and are still used in processions, symbolic and religious events, and in juggling entertainment. In some countries, the word "torch" is used as the term for a battery-operated portable light. From the Old French ""torche"" meaning "twisted thing", hence "torch formed of twisted tow dipped in wax", probably from Vulgar Latin *"torca", alteration of Late Latin "torqua", variant of classical Latin "torques" "collar of twisted metal", from "torquere" "to twist". Torch construction has


title: Tiger content: Tiger The tiger ("Panthera tigris") is the largest cat species, most recognizable for its pattern of dark vertical stripes on reddish-orange fur with a lighter underside. The species is classified in the genus "Panthera" with the lion, jaguar, leopard, and snow leopard. It is an apex predator, primarily preying on ungulates such as deer and bovids. It is territorial and generally a solitary but social predator, often requiring large contiguous areas of habitat that support its prey requirements. This, coupled with the fact that it is indigenous to some of the more densely populated places on Earth, has caused significant


title: Tiger content: conflicts with humans. The tiger is among the most recognisable and popular of the world's charismatic megafauna. It featured prominently in ancient mythology and folklore and continues to be depicted in modern films and literature, appearing on many flags, coats of arms and as mascots for sporting teams. The tiger is the national animal of India, Bangladesh, Malaysia and South Korea. The Middle English "tigre" and Old English "tigras" (plural) derive from Old French "tigre", from Latin "tigris". This was a borrowing of Classical Greek "τίγρις" (transliterated as "tigris", the modern species name), a foreign borrowing of unknown origin meaning


title: Tiger content: "tiger" as well as the river Tigris. The original source may have been Persian "tigra" (pointed or sharp), and Avestan "tigrhi" (arrow), perhaps referring to the speed of the tiger's leap, although these words are not known to have any meanings associated with tigers. The genus name "Panthera" is traceable to Old French "pantère", from Latin "panthera", from Ancient Greek "panther", most likely with the original meaning "yellowish animal", or from "pandarah" meaning "whitish-yellow", possibly related to Sanskrit "pundarikas" (tiger). The derivation from Greek "pan-" ("all") and "ther" ("beast") is likely incorrect folk etymology. In 1758, Carl Linnaeus described the


title: Tiger content: tiger in his work "Systema Naturae" and gave it the scientific name "Felis tigris". In 1929, the British taxonomist Reginald Innes Pocock subordinated the species under the genus "Panthera" using the scientific name "Panthera tigris". The tiger's closest living relatives were previously thought to be the "Panthera" species lion, leopard and jaguar. Results of genetic analysis indicate that about 2.88 million years ago, the tiger and the snow leopard lineages diverged from the other "Panthera" species, and that both may be more closely related to each other than to the lion, leopard and jaguar. Results of a phylogeographic study indicate


title: Tiger content: that all living tigers had a common ancestor 72,000–108,000 years ago. Fossil remains of the Longdan tiger were found in the Gansu province of northwestern China. This species lived at the beginning of the Pleistocene, about 2 million years ago, and is considered to be a sister taxon of the modern tiger. It was about the size of a jaguar and probably had a different coat pattern. Despite being considered more "primitive", the Longdan tiger was functionally and possibly ecologically similar to the modern tiger. As it lived in northwestern China, that may have been where the tiger lineage originated.


title: Tiger content: Tigers grew in size, possibly in response to adaptive radiations of prey species like deer and bovids, which may have occurred in Southeast Asia during the early Pleistocene. The earliest fossils of true tigers are known from the early and middle Pleistocene deposits in China and Sumatra, around 2 million years ago. The Trinil tiger ("Panthera tigris trinilensis") lived about 1.2 million years ago and is known from fossils found at Trinil in Java. The Wanhsien, Ngandong, Trinil and Japanese tigers became extinct in prehistoric times. Tigers first reached India and northern Asia in the late Pleistocene, reaching eastern Beringia,


title: Tiger content: Japan, and Sakhalin. Some fossil skulls are morphologically distinct from lion skulls, which could indicate tiger presence in Alaska during the last glacial period, about 100,000 years ago. Fossils found in Japan indicate the local tigers were smaller than the mainland forms, possibly due to insular dwarfism. The potential tiger range during the Late Pleistocene and Holocene was predicted applying ecological niche modelling based on more than 500 tiger locality records combined with bioclimatic data. The resulting model shows a contiguous tiger range from southern India to Siberia at the Last Glacial Maximum, indicating an unobstructed gene flow between tiger


title: Tiger content: populations in mainland Asia throughout the Late Pleistocene and Holocene. The tiger populations on the Sunda Islands and mainland Asia were possibly separated during interglacial periods. The tiger's full genome sequence was published in 2013. It was found to have similar repeat composition than other cat genomes and an appreciably conserved synteny. Following Linnaeus's first descriptions of the species, several tiger specimens were described and proposed as subspecies. The validity of several tiger subspecies was questioned in 1999. Most putative subspecies described in the 19th and 20th centuries were distinguished on basis of fur length and coloration, striping patterns and


title: Tiger content: body size, hence characteristics that vary widely within populations. Morphologically, tigers from different regions vary little, and gene flow between populations in those regions is considered to have been possible during the Pleistocene. Therefore, it was proposed to recognize only two tiger subspecies as valid, namely "P. t. tigris" in mainland Asia, and "P. t. sondaica" in the Greater Sunda Islands and possibly in Sundaland. Results of craniological analysis of 111 tiger skulls from Southeast Asian range countries indicate that Sumatran tiger skulls differ from Indochinese and Javan tiger skulls, whereas Bali tiger skulls are similar in size to Javan


title: Tiger content: tiger skulls. The authors proposed to classify Sumatran and Javan tiger as distinct species, "P. sumatrae" and "P. sondaica" with Bali tiger as subspecies "P. sondaica balica". In 2015, morphological, ecological and molecular traits of all putative tiger subspecies were analysed in a combined approach. Results support distinction of the two evolutionary groups continental and Sunda tigers. The authors proposed recognition of only two subspecies, namely "P. t. tigris" comprising the Bengal, Malayan, Indochinese, South Chinese, Siberian and Caspian tiger populations, and "P. t. sondaica" comprising the Javan, Bali and Sumatran tiger populations. The authors also noted that this reclassification


title: Tiger content: will affect tiger conservation management. One conservation specialist welcomed this proposal as it would make captive breeding programmes and future rewilding of zoo-born tigers easier. One geneticist was sceptical of this study and maintained that the currently recognised nine subspecies can be distinguished genetically. In 2017, the Cat Classification Task Force of the IUCN Cat Specialist Group revised felid taxonomy and now recognizes the tiger populations in continental Asia as "P. t. tigris", and those in the Sunda Islands as "P. t. sondaica". The following tables are based on the classification of the species "Panthera tigris" provided in "Mammal Species


title: Tiger content: of the World". It also reflects the classification used by the Cat Classification Task Force in 2017: Lions have been known to breed with tigers in captivity to create hybrids called ligers and tigons. They share physical and behavioural qualities of both parent species. Such hybrids were once commonly bred in zoos, but this is now discouraged due to the emphasis on conservation. The liger is a cross between a male lion and a tigress. Ligers are typically between in length, and can weigh between or more. Because the lion sire passes on a growth-promoting gene, but the corresponding growth-inhibiting


title: Tiger content: gene from the female tiger is absent, ligers grow far larger than either parent species. The less common tigon is a cross between a lioness and a male tiger. Because the male tiger does not pass on a growth-promoting gene and the lioness passes on a growth inhibiting gene, tigons are around the same size as their parents. Females are sometimes fertile and have occasionally given birth to litigons when mated to a male Asiatic lion. The tiger has a muscular body with powerful forelimbs, a large head and a tail that is about half the length of its body.


title: Tiger content: Its pelage is dense and heavy, and colouration varies between shades of orange and brown with white ventral areas and distinctive vertical black stripes that are unique in each individual. Stripes are likely advantageous for camouflage in vegetation such as long grass with strong vertical patterns of light and shade. The tiger is one of only a few striped cat species; it is not known why spotted patterns and rosettes are the more common camouflage pattern among felids. A tiger's coat pattern is still visible when it is shaved. This is not due to skin pigmentation, but to the stubble


title: Tiger content: and hair follicles embedded in the skin, similar to human beards (colloquially five o'clock shadow), and is in common with other big cats. They have a mane-like heavy growth of fur around the neck and jaws and long whiskers, especially in males. The pupils are circular with yellow irises. The small, rounded ears have a prominent white spot on the back, surrounded by black. These false "eyespots", called ocelli, apparently play an important role in intraspecies communication. The tiger's skull is similar to a lion's skull, with the frontal region usually less depressed or flattened, and a slightly longer postorbital


title: Tiger content: region. The lion skull shows broader nasal openings. Due to the variation in skull sizes of the two species, the structure of the lower jaw is a reliable indicator for their identifcation. The tiger has fairly stout teeth; its somewhat curved canines are the longest among living felids with a crown height of up to . Tigers are the most variable in size of all big cat species. There is a notable sexual dimorphism between males and females, with the latter being consistently smaller than males. The size difference between males and females is proportionally greater in the large tiger


title: Tiger content: subspecies, with males weighing up to 1.7 times more than females. Males also have wider forepaw pads than females, enabling gender to be told from tracks. Generally, males vary in total length from and weigh between with skull length ranging from . Females vary in total length from , weigh with skull length ranging from . The heaviest wild tiger ever reported had a total body length of over curves. In either sex, the tail represents about of total length. Large male Siberian tigers reach a total length of more than over curves and between the pegs, with a weight


title: Tiger content: of up to at least . This is considerably larger than the weight of reached by the Sumatran tiger. At the shoulder, tigers may variously stand tall. The heaviest captive tiger was a Siberian tiger at . It has been hypothesised that body size of different tiger populations may be correlated with climate and be explained by thermoregulation and Bergmann's rule, or by distribution and size of available prey species. However, the heaviest wild tiger on record was a Bengal tiger from north India which was shot in 1967. It allegedly weighed , though it should be noted that it


title: Tiger content: had a heavy meal before it was killed, without which it would have weighed significantly less. Likewise, the record length for a tiger's skull was "over the bone" for a tiger that was shot in 1927 in northern India. The Bengal and Siberian tigers are amongst the tallest cats in shoulder height. They are also ranked with the Caspian tiger among the biggest cats that ever existed. However, on average, a wild adult male Siberian tiger at body weight is outweighed by an adult, male Bengal tiger at . A well-known allele found only in the Bengal population produces the


title: Tiger content: white tiger, a colour variant first recorded in the Mughal Empire in the late 16th and early 17th centuries. Genetically, whiteness is recessive: a cub is white only when both parents carry the allele for whiteness. It is not albinism, pigment being evident in the white tiger's stripes and in their blue eyes. The causative mutation changes a single amino acid in the transporter protein SLC45A2. White tigers are more frequently bred in captivity, where the comparatively small gene pool can lead to inbreeding. This has given white tigers a greater likelihood of being born with physical defects, such as


title: Tiger content: cleft palate, scoliosis (curvature of the spine), and strabismus (squint). True albino tigers do exist and may be termed "snow white" tigers. In this colour morph, the stripes are extremely faint on the body while the tail has pale reddish-brown rings. Golden tigers, another colour morph, have pale golden pelage with a blond tone and reddish-brown stripes. These types are rarely recorded in the wild. Both snow white and golden tiger are homozygous for the "CORIN" gene. Tiger populations once ranged widely across Asia, from the Black Sea in the west to Kolyma and Sumatra in the east and to


title: Tiger content: the Indian Ocean in the south. Over the past 100 years, the species has lost 93% of its historic range and has been extirpated from Western and Central Asia, the islands of Java and Bali and large areas of Southeast, South and East Asia. Today, its ecological habitats include the Siberian taiga as well as open grasslands and tropical mangrove swamps, and it has been classified as endangered in the IUCN Red List. Major reasons for the population decline include habitat destruction, habitat fragmentation and poaching. The extent of area inhabited by tigers is estimated at less than , a


title: Tiger content: 41% decline from that of the mid-1990s. The global wild population is estimated to number between 3,062 and 3,948 individuals, down from around 100,000 at the start of the 20th century, with most remaining populations occurring in small pockets isolated from each other and with 2,000 of the total population living on the Indian subcontinent. In 2016, an estimate of a global wild tiger population of approximately 3,890 individuals was presented during the Third Asia Ministerial Conference on Tiger Conservation. The WWF subsequently declared that the world's count of wild tigers had risen for the first time in a century.


title: Tiger content: At the end of the last glacial period about 20,000 years ago, the tiger was widespread from Eastern Anatolia Region and Mesopotamia, in Central Asia to eastern Siberia and South and Southeast Asia to the Indonesian islands of Java, Bali and Sumatra. Today, tigers are regionally extinct in Afghanistan, Ukraine, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Iran, Pakistan and Singapore. Fossil remains of tigers were excavated in Sri Lanka, China, Japan, Sarawak and the Philippine island of Palawan dating to the late Pliocene, Pleistocene and Early Holocene. The Bornean tiger was apparently present in Borneo between the Late Pleistocene to the Holocene,


title: Tiger content: but may have gone extinct in prehistoric times. During the 20th century, tigers became extinct in Western and Central Asia, and in a number of Sunda Islands, and were restricted to isolated pockets in the remaining parts of their range. They were extirpated on the island of Bali in the 1940s, around the Caspian Sea in the 1970s, and on Java in the 1980s. This was the result of habitat loss and the ongoing killing of tigers and tiger prey. Today, their significantly fragmented and depopulated range extends eastward from India to Bangladesh, Bhutan, Nepal, Myanmar, Thailand, Cambodia, Laos, Vietnam,


title: Tiger content: China, Malaysia, Indonesia, North Korea and Russia. The northern limit of their range is close to the Amur River in southeastern Siberia. The only large island they still inhabit is Sumatra. Since the beginning of the 20th century, tigers' historical range has shrunk by 93%. In the decade from 1997 to 2007, the estimated area known to be occupied by tigers has declined by 41%. The tiger occupies a wide range of habitat types, but will usually require sufficient cover, proximity to water, and an abundance of prey. It prefers dense vegetation, for which its camouflage colouring is ideally suited,


title: Tiger content: and where a single predator is not at a disadvantage compared with the multiple cats in a pride. A further habitat requirement is the placement of suitably secluded den locations, which may consist of caves, large hollow trees, or dense vegetation. The Bengal tiger in particular lives in many types of forests, including wet, evergreen, and the semi-evergreen forests of Assam and eastern Bengal, swampy mangrove forests of the Ganges Delta, deciduous forest in the Terai, and thorn forests in the Western Ghats. In various parts of its range it inhabits or had inhabited additionally partially open grassland and savanna


title: Tiger content: as well as taiga forests and rocky habitats. When not subject to human disturbance, the tiger is mainly diurnal. It does not often climb trees but cases have been recorded. It is a strong swimmer and often bathes in ponds, lakes and rivers, thus keeping cool in the heat of the day. Individuals can cross rivers up to wide and can swim up to in a day. During the 1980s, a tiger named "Genghis" in Ranthambhore National Park was observed frequently hunting prey through deep lake water. The tiger is a long-ranging species, and individuals disperse over distances of up


title: Tiger content: to to reach tiger populations in other areas. Radio-collared tigers in Chitwan National Park started dispersing from their natal areas earliest at the age of 19 months. Four females dispersed between , and 10 males between . None of them crossed open cultivated areas that were more than wide, but moved through forested habitat. Adult tigers lead largely solitary lives. They establish and maintain territories but have much wider home ranges within which they roam. Resident adults of either sex generally confine their movements to their home ranges, within which they satisfy their needs and those of their growing cubs.


title: Tiger content: Individuals sharing the same area are aware of each other's movements and activities. The size of the home range mainly depends on prey abundance, geographic area and sex of the individual. In India, home ranges appear to be while in Manchuria, they range from . In Nepal, defended territories are recorded to be for males and for females. Young female tigers establish their first territories close to their mother's. The overlap between the female and her mother's territory reduces with time. Males, however, migrate further than their female counterparts and set out at a younger age to mark out their


title: Tiger content: own area. A young male acquires territory either by seeking out an area devoid of other male tigers, or by living as a transient in another male's territory until he is older and strong enough to challenge the resident male. Young males seeking to establish themselves thereby comprise the highest mortality rate (30–35% per year) amongst adult tigers. To identify his territory, the male marks trees by spraying urine and anal gland secretions, as well as marking trails with scat and marking trees or the ground with their claws. Females also use these "scrapes", as well as urine and scat


title: Tiger content: markings. Scent markings of this type allow an individual to pick up information on another's identity, sex and reproductive status. Females in oestrus will signal their availability by scent marking more frequently and increasing their vocalisations. Although for the most part avoiding each other, tigers are not always territorial and relationships between individuals can be complex. An adult of either sex will sometimes share its kill with others, even those who may not be related to them. George Schaller observed a male share a kill with two females and four cubs. Unlike male lions, male tigers allow females and cubs


title: Tiger content: to feed on the kill before the male is finished with it; all involved generally seem to behave amicably, in contrast to the competitive behaviour shown by a lion pride. In his book "Tiger", Stephen Mills describes a social eating event witnessed by Valmik Thapar and Fateh Singh Rathore in Ranthambhore National Park thus: Occasionally, male tigers participate in raising cubs, usually their own, but this is extremely rare and not always well understood. In May 2015, Amur tigers were photographed by camera traps in the Sikhote-Alin Bioshpere Reserve. The photos show a male Amur tiger pass by, followed by


title: Tiger content: a female and three cubs within the span of about two minutes. In Ranthambore, a male Bengal tiger raised and defended two orphaned female cubs after their mother had died of illness. The cubs remained under his care, he supplied them with food, protected them from his rival and sister, and apparently also trained them. Male tigers are generally more intolerant of other males within their territories than females are of other females. Territory disputes are usually solved by displays of intimidation rather than outright aggression. Several such incidents have been observed in which the subordinate tiger yielded defeat by


title: Tiger content: rolling onto its back and showing its belly in a submissive posture. Once dominance has been established, a male may tolerate a subordinate within his range, as long as they do not live in too close quarters. The most aggressive disputes tend to occur between two males when a female is in oestrus, and may rarely result in the death of one of the males. Facial expressions include the "defense threat", where an individual bares its teeth, flattens its ears and its pupils enlarge. Both males and females show a flehmen response, a characteristic grimace, when sniffing urine markings but


title: Tiger content: flehmen is more often associated with males detecting the markings made by tigresses in oestrus. Like other "Panthera", tigers roar, particularly in aggressive situations, during the mating season or when making a kill. There are two different roars: the "true" roar is made using the hyoid apparatus and forced through an open mouth as it progressively closes, and the shorter, harsher "coughing" roar is made with the mouth open and teeth exposed. The "true" roar can be heard at up to away and is sometimes emitted three or four times in succession. When tense, tigers will moan, a sound similar


title: Tiger content: to a roar but more subdued and made when the mouth is partially or completely closed. Moaning can be heard away. Chuffing, soft, low-frequency snorting similar to purring in smaller cats, is heard in more friendly situations. Other vocal communications include grunts, woofs, snarls, miaows, hisses and growls. In the wild, tigers mostly feed on large and medium-sized animals, preferring ungulates weighing at least . They typically have little or no deleterious effect on their prey populations. Sambar deer, chital, barasingha, wild boar, gaur, nilgai and both water buffalo and domestic buffalo are the tiger's prey in India. They also


title: Tiger content: prey on other predators, including dogs, leopards, pythons, sloth bears, and crocodiles. In Siberia, the main prey species are Manchurian wapiti and wild boar (the two species comprising nearly 80% of the prey selected) followed by sika deer, moose, roe deer, and musk deer. Asiatic black bears and Ussuri brown bears may also fall prey to tigers, and they constitute up to 40.7% of the diet of Siberian tigers depending on local conditions and the bear populations. In Sumatra, prey include sambar deer, muntjac, wild boar, Malayan tapir and orangutan. Like many predators, tigers are opportunistic and may eat much


title: Tiger content: smaller prey, such as monkeys, peafowl and other ground-based birds, hares, porcupines, and fish. Tigers generally do not prey on fully grown adult Asian elephants and Indian rhinoceros but incidents have been reported. More often, it is the more vulnerable small calves that are taken. However, occasionally adult rhinoceros have in fact fallen victims to tigers, as has been documented in at least three separate incidents. Tigers have been reported attacking and killing elephants ridden by humans during tiger hunts in the 19th century. When in close proximity to humans, tigers will also sometimes prey on such domestic livestock as


title: Tiger content: cattle, horses, and donkeys. Old or wounded tigers, unable to catch wild prey, can become man-eaters; this pattern has recurred frequently across India. An exception is in the Sundarbans, where healthy tigers prey upon fishermen and villagers in search of forest produce, humans thereby forming a minor part of the tiger's diet. Although almost exclusively carnivorous, tigers will occasionally eat vegetation for dietary fibre such as fruit of the slow match tree. Tigers are thought to be mainly nocturnal predators, but in areas where humans are absent, remote-controlled, hidden camera traps recorded them hunting in daylight. They generally hunt alone


title: Tiger content: and ambush their prey as most other cats do, overpowering them from any angle, using their body size and strength to knock the prey off balance. Successful hunts usually require the tiger to almost simultaneously leap onto its quarry, knock it over, and grab the throat or nape with its teeth. Despite their large size, tigers can reach speeds of about but only in short bursts; consequently, tigers must be close to their prey before they break cover. If the prey catches wind of the tiger's presence before this, the tiger usually abandons the hunt rather than chase prey or


title: Tiger content: battle it head-on. Horizontal leaps of up to have been reported, although leaps of around half this distance are more typical. One in 2 to 20 hunts, including stalking near potential prey, ends in a successful kill. When hunting larger animals, tigers prefer to bite the throat and use their powerful forelimbs to hold onto the prey, often simultaneously wrestling it to the ground. The tiger remains latched onto the neck until its target dies of strangulation. By this method, gaurs and water buffaloes weighing over a ton have been killed by tigers weighing about a sixth as much. Although


title: Tiger content: they can kill healthy adults, tigers often select the calves or infirm of very large species. Healthy adult prey of this type can be dangerous to tackle, as long, strong horns, legs and tusks are all potentially fatal to the tiger. No other extant land predator routinely takes on prey this large on its own. Whilst hunting sambars, which comprise up to 60% of their prey in India, tigers have reportedly made a passable impersonation of the male sambar's rutting call to attract them. With smaller prey, such as monkeys and hares, the tiger bites the nape, often breaking the


title: Tiger content: spinal cord, piercing the windpipe, or severing the jugular vein or common carotid artery. Though rarely observed, some tigers have been recorded to kill prey by swiping with their paws, which are powerful enough to smash the skulls of domestic cattle, and break the backs of sloth bears. After killing their prey, tigers sometimes drag it to conceal it in vegetative cover, usually pulling it by grasping with their mouths at the site of the killing bite. This, too, can require great physical strength. In one case, after it had killed an adult gaur, a tiger was observed to drag


title: Tiger content: the massive carcass over a distance of . When 13 men simultaneously tried to drag the same carcass later, they were unable to move it. An adult tiger can go for up to two weeks without eating, then gorge on of flesh at one time. In captivity, adult tigers are fed of meat a day. Tigers usually prefer to eat prey they have caught themselves, but are not above eating carrion in times of scarcity and may even pirate prey from other large carnivores. Although predators typically avoid one another, if a prey item is under dispute or a serious


title: Tiger content: competitor is encountered, displays of aggression are common. If these are not sufficient, the conflicts may turn violent; tigers may kill competitors as leopards, dholes, striped hyenas, wolves, bears, pythons, and crocodiles on occasion. Tigers may also prey on these competitors. Attacks on smaller predators, such as badgers, lynxes, and foxes, are almost certainly predatory. Crocodiles, bears, and large packs of dholes may win conflicts against tigers and in some cases even kill them. The considerably smaller leopard avoids competition from tigers by hunting at different times of the day and hunting different prey. In India's Nagarhole National Park, most


title: Tiger content: prey selected by leopards were from against a preference for prey weighing over in the tigers. The average prey weight in the two respective big cats in India was against . With relatively abundant prey, tigers and leopards were seen to successfully coexist without competitive exclusion or interspecies dominance hierarchies that may be more common to the African savanna, where the leopard exists with the lion. Golden jackals may feed on the tiger's kills. Tigers appear to inhabit the deep parts of a forest while smaller predators like leopards and dholes are pushed closer to the fringes. Mating can occur


title: Tiger content: all year round, but is more common between November and April. A female is only receptive for three to six days. Mating is frequent and noisy during that time. Gestation ranges from 93 to 112 days, with an average of 103 to 105 days. Litters consist of one or three cubs, rarely as many as six. Cubs weigh from each at birth, and are born blind. Females lactate for five to six months. The female rears them alone, with the birth site and maternal den in a sheltered location such as a thicket, cave or rocky crevice. The father generally


title: Tiger content: takes no part in rearing. Unrelated wandering male tigers often kill cubs to make the female receptive, since the tigress may give birth to another litter within five months if the cubs of the previous litter are lost. The mortality rate of tiger cubs is about 50% in the first two years. Few other predators attack tiger cubs due to the diligence and ferocity of the mother. Apart from humans and other tigers, common causes of cub mortality are starvation, freezing, and accidents. A dominant cub emerges in most litters, usually a male. This cub is more active than its


title: Tiger content: siblings and takes the lead in their play, eventually leaving its mother and becoming independent earlier. The cubs open their eyes at six to fourteen days old. By eight weeks, the cubs make short ventures outside the den with their mother, although they do not travel with her as she roams her territory until they are older. The cubs are nursed for three to six months. Around the time they are weaned, they start to accompany their mother on territorial walks and they are taught how to hunt. The cubs often become capable (and nearly adult size) hunters at eleven


title: Tiger content: months old. The cubs become independent around eighteen months of age, but it is not until they are around two to two and a half years old that they fully separate from their mother. Females reach sexual maturity at three to four years, whereas males do so at four to five years. The oldest recorded captive tiger lived for 26 years. A wild specimen, having no natural predators, could in theory live to a comparable age. Generation length of the tiger is about eight years. Major threats to the tiger include habitat destruction, habitat fragmentation and poaching for fur and


title: Tiger content: body parts, which have simultaneously greatly reduced tiger populations in the wild. In India, only 11% of the historical tiger habitat remains due to habitat fragmentation. Demand for tiger parts for use in traditional Chinese medicine has also been cited as a major threat to tiger populations. At the start of the 20th century, it was estimated there were over 100,000 tigers in the wild, but the population has dwindled outside of captivity to between 1,500 and 3,500. Some estimates suggest that there are fewer than 2,500 mature breeding individuals, with no subpopulation containing more than 250 mature breeding individuals.


title: Tiger content: The global wild tiger population was estimated by the World Wide Fund for Nature at 3,200 in 2011 and 3,890 in 2015—"Vox" reported that this was the first increase in a century. India is home to the world's largest population of wild tigers. A 2014 census estimated a population of 2,226, a 30% increase since 2011. In 1973, India's "Project Tiger", started by Indira Gandhi, established numerous tiger reserves. The project was credited with tripling the number of wild Bengal tigers from some 1,200 in 1973 to over 3,500 in the 1990s, but a 2007 census showed that numbers had


title: Tiger content: dropped back to about 1,400 tigers because of poaching. Following the report, the Indian government pledged $153 million to the initiative, set up measures to combat poaching, promised funds to relocate up to 200,000 villagers in order to reduce human-tiger interactions, and set up eight new tiger reserves. India also reintroduced tigers to the Sariska Tiger Reserve and by 2009 it was claimed that poaching had been effectively countered at Ranthambore National Park. In the 1940s, the Siberian tiger was on the brink of extinction with only about 40 animals remaining in the wild in Russia. As a result, anti-poaching


title: Tiger content: controls were put in place by the Soviet Union and a network of protected zones (zapovedniks) were instituted, leading to a rise in the population to several hundred. Poaching again became a problem in the 1990s, when the economy of Russia collapsed. The major obstacle in preserving the species is the enormous territory individual tigers require (up to 450 km needed by a single female and more for a single male). Current conservation efforts are led by local governments and NGO's in concert with international organisations, such as the World Wide Fund for Nature and the Wildlife Conservation Society. The


title: Tiger content: competitive exclusion of wolves by tigers has been used by Russian conservationists to convince hunters to tolerate the big cats. Tigers have less impact on ungulate populations than do wolves, and are effective in controlling the latter's numbers. In 2005, there were thought to be about 360 animals in Russia, though these exhibited little genetic diversity. However, in a decade later, the Siberian tiger census was estimated from 480 to 540 individuals. Having earlier rejected the Western-led environmentalist movement, China changed its stance in the 1980s and became a party to the CITES treaty. By 1993 it had banned the


title: Tiger content: trade in tiger parts, and this diminished the use of tiger bones in traditional Chinese medicine. The Tibetan people's trade in tiger skins has also been a threat to tigers. The pelts were used in clothing, tiger-skin "chuba" being worn as fashion. In 2006 the 14th Dalai Lama was persuaded to take up the issue. Since then there has been a change of attitude, with some Tibetans publicly burning their chubas. In 1994, the Indonesian Sumatran Tiger Conservation Strategy addressed the potential crisis that tigers faced in Sumatra. The Sumatran Tiger Project (STP) was initiated in June 1995 in and


title: Tiger content: around the Way Kambas National Park in order to ensure the long-term viability of wild Sumatran tigers and to accumulate data on tiger life-history characteristics vital for the management of wild populations. By August 1999, the teams of the STP had evaluated 52 sites of potential tiger habitat in Lampung Province, of which only 15 these were intact enough to contain tigers. In the framework of the STP a community-based conservation programme was initiated to document the tiger-human dimension in the park in order to enable conservation authorities to resolve tiger-human conflicts based on a comprehensive database rather than anecdotes


title: Tiger content: and opinions. The Wildlife Conservation Society and Panthera Corporation formed the collaboration "Tigers Forever", with field sites including the world's largest tiger reserve, the Hukaung Valley in Myanmar. Other reserves were in the Western Ghats in India, Thailand, Laos, Cambodia, the Russian Far East covering in total about . Tigers have been studied in the wild using a variety of techniques. Tiger population have been estimated using plaster casts of their pugmarks, although this method was criticized as being inaccurate. More recent techniques include the use of camera traps and studies of DNA from tiger scat, while radio-collaring has been


title: Tiger content: used to track tigers in the wild. Tiger spray has been found to be just as good, or better, as a source of DNA than scat. The exact number of wild tigers is unknown, as many estimates are outdated or educated guesses; few estimates are based on reliable scientific censuses. The table shows estimates according to IUCN Red List accounts and range country governments dating from 2009 to April 2016. In 1978, the Indian conservationist Billy Arjan Singh attempted to rewild a tiger in Dudhwa National Park; this was the captive-bred tigress Tara. Soon after the release, numerous people were


title: Tiger content: killed and eaten by a tigress that was subsequently shot. Government officials claimed it was Tara, though Singh disputed this. Further controversy broke out with the discovery that Tara was partly Siberian tiger. The organisation Save China's Tigers has attempted to rewild the South China tigers, with a breeding and training programme in a South African reserve known as Laohu Valley Reserve (LVR) and eventually reintroduce them to the wild of China. A future rewilding project was proposed for Siberian tigers set to be reintroduced to northern Russia's Pleistocene park. The Siberian tigers sent to Iran for a captive breeding


title: Tiger content: project in Tehran are set to be rewilded and reintroduced to the Miankaleh peninsula, to replace the now extinct Caspian tigers. The tiger has been one of the big five game animals of Asia. Tiger hunting took place on a large scale in the early 19th and 20th centuries, being a recognised and admired sport by the British in colonial India as well as the maharajas and aristocratic class of the erstwhile princely states of pre-independence India. A single maharaja or English hunter could claim to kill over a hundred tigers in their hunting career. Tiger hunting was done by


title: Tiger content: some hunters on foot; others sat up on "machans" with a goat or buffalo tied out as bait; yet others on elephant-back. Historically, tigers have been hunted at a large scale so their famous striped skins could be collected. The trade in tiger skins peaked in the 1960s, just before international conservation efforts took effect. By 1977, a tiger skin in an English market was considered to be worth US$4,250. Many people in China and other parts of Asia have a belief that various tiger parts have medicinal properties, including as pain killers and aphrodisiacs. There is no scientific evidence


title: Tiger content: to support these beliefs. The use of tiger parts in pharmaceutical drugs in China is already banned, and the government has made some offences in connection with tiger poaching punishable by death. Furthermore, all trade in tiger parts is illegal under the Convention on International Trade in Endangered Species of Wild Fauna and Flora and a domestic trade ban has been in place in China since 1993. However, the trading of tiger parts in Asia has become a major black market industry and governmental and conservation attempts to stop it have been ineffective to date. Almost all black marketers engaged


title: Tiger content: in the trade are based in China and have either been shipped and sold within in their own country or into Taiwan, South Korea or Japan. The Chinese subspecies was almost completely decimated by killing for commerce due to both the parts and skin trades in the 1950s through the 1970s. Contributing to the illegal trade, there are a number of tiger farms in the country specialising in breeding the cats for profit. It is estimated that between 5,000 and 10,000 captive-bred, semi-tame animals live in these farms today. However, many tigers for traditional medicine black market are wild ones


title: Tiger content: shot or snared by poachers and may be caught anywhere in the tiger's remaining range (from Siberia to India to the Malay Peninsula to Sumatra). In the Asian black market, a tiger penis can be worth the equivalent of around $300 U.S. dollars. In the years of 1990 through 1992, 27 million products with tiger derivatives were found. In July 2014 at an international convention on endangered species in Geneva, Switzerland, a Chinese representative admitted for the first time his government was aware trading in tiger skins was occurring in China. Wild tigers that have had no prior contact with


title: Tiger content: humans actively avoid interactions with humans. However, tigers cause more human deaths through direct attack than any other wild mammal. Attacks are occasionally provoked, as tigers lash out after being injured while they themselves are hunted. Attacks can be provoked accidentally, as when a human surprises a tiger or inadvertently comes between a mother and her young, or as in a case in rural India when a postman startled a tiger, used to seeing him on foot, by riding a bicycle. Occasionally tigers come to view people as prey. Such attacks are most common in areas where population growth, logging,


title: Tiger content: and farming have put pressure on tiger habitats and reduced their wild prey. Most man-eating tigers are old, missing teeth, and unable to capture their preferred prey. For example, the Champawat Tiger, a tigress found in Nepal and then India, had two broken canines. She was responsible for an estimated 430 human deaths, the most attacks known to be perpetrated by a single wild animal, by the time she was shot in 1907 by Jim Corbett. According to Corbett, tiger attacks on humans are normally in daytime, when people are working outdoors and are not keeping watch. Early writings tend


title: Tiger content: to describe man-eating tigers as cowardly because of their ambush tactics. Man-eaters have been a particular problem in recent decades in India and Bangladesh, especially in Kumaon, Garhwal and the Sundarbans mangrove swamps of Bengal, where some healthy tigers have hunted humans. Because of rapid habitat loss attributed to climate change, tiger attacks have increased in the Sundarbans. The Sundarbans area had 129 human deaths from tigers from 1969 to 1971. In the 10 years prior to that period, about 100 attacks per year in the Sundarbans, with a high of around 430 in some years of the 1960s. Unusually,


title: Tiger content: in some years in the Sundarbans, more humans are killed by tigers than vice versa. In 1972, India's production of honey and beeswax dropped by 50% when at least 29 people who gathered these materials were devoured. In 1986 in the Sundarbans, since tigers almost always attack from the rear, masks with human faces were worn on the back of the head, on the theory that tigers usually do not attack if seen by their prey. This decreased the number of attacks only temporarily. All other means to prevent attacks, such as providing more prey or using electrified human dummies,


title: Tiger content: worked less well. In 2018, Indian authorities used the perfume "Obsession" by Calvin Klein, containing musk, to attempt to attract and thus trap a wild tiger, called 'T-1', that had attacked and killed more than a dozen humans. Ultimately, the tiger was killed in self-defence, after charging those attempting to tranquilise her. At least 27 people were killed or seriously injured by captive tigers in the United States from 1998 to 2001. In some cases, rather than being predatory, tiger attacks on human seem to be territorial in nature. At least in one case, a tigress with cubs killed eight


title: Tiger content: people entering her territory without consuming them at all. In Ancient Roman times, tigers were kept in menageries and amphitheatres to be exhibited, trained and paraded, and were often provoked to fight humans and exotic beasts. Since the 17th century, tigers, being rare and ferocious, were sought after to keep at European castles as symbols of their owners' power. Tigers became central zoo and circus exhibits in the 18th century: a tiger could cost up to 4,000 francs in France (for comparison, a professor of the Beaux-Arts at Lyons earned only 3,000 francs a year), or up to $3,500 in


title: Tiger content: the United States, where a lion cost no more than $1,000. China (2007) had over 4,000 captive tigers, of which 3,000 were held by about twenty larger facilities, with the rest held by some 200 smaller facilities. The USA (2011) had 2,884 tigers in 468 facilities. Nineteen states have banned private ownership of tigers, fifteen require a license, and sixteen states have no regulation. Genetic ancestry of 105 captive tigers from fourteen countries and regions showed that forty-nine animals belonged distinctly to five subspecies; fifty-two animals had mixed subspecies origins. As such, "many Siberian tigers in zoos today are actually


title: Tiger content: the result of crosses with Bengal tigers." The Tiger Species Survival Plan has condemned the breeding of white tigers, alleging they are of mixed ancestry and of unknown lineage. The genes responsible for white colouration are represented by 0.001% of the population. The disproportionate growth in numbers of white tigers points to inbreeding among homozygous recessive individuals. This would lead to inbreeding depression and loss of genetic variability. Tigers and their superlative qualities have been a source of fascination for mankind since ancient times, and they are routinely visible as important cultural and media motifs. They are also considered one


title: Tiger content: of the charismatic megafauna, and are used as the face of conservation campaigns worldwide. In a 2004 online poll conducted by cable television channel Animal Planet, involving more than 50,000 viewers from 73 countries, the tiger was voted the world's favourite animal with 21% of the vote, narrowly beating the dog. In Chinese myth and culture, the tiger is one of the 12 animals of the Chinese zodiac. In Chinese art, the tiger is depicted as an earth symbol and equal rival of the Chinese dragon – the two representing matter and spirit respectively. The Southern Chinese martial art Hung


title: Tiger content: Ga is based on the movements of the tiger and the crane. In Imperial China, a tiger was the personification of war and often represented the highest army general (or present day defense secretary), while the emperor and empress were represented by a dragon and phoenix, respectively. The White Tiger () is one of the Four Symbols of the Chinese constellations. It is sometimes called the White Tiger of the West (), and it represents the west and the autumn season. In Buddhism, the tiger is one of the Three Senseless Creatures, symbolising anger, with the monkey representing greed and


title: Tiger content: the deer lovesickness. The Tungusic peoples considered the Siberian tiger a near-deity and often referred to it as "Grandfather" or "Old man". The Udege and Nanai called it "Amba". The Manchu considered the Siberian tiger as "Hu Lin," the king. In Hinduism, the god Shiva wears and sits on tiger skin. The ten-armed warrior goddess Durga rides the tigress (or lioness) Damon into battle. In southern India the god Ayyappan was associated with a tiger. The weretiger replaces the werewolf in shapeshifting folklore in Asia; in India they were evil sorcerers, while in Indonesia and Malaysia they were somewhat more


title: Tiger content: benign. In the Hindu epic Mahabharata, tigers are fiercer and more ruthless than lions. The tiger's tail appears in stories from countries including China and Korea, it being generally inadvisable to grasp a tiger by the tail. In William Blake's poem in the "Songs of Experience", titled "The Tyger," the tiger is a menacing and fearful animal. In Yann Martel's 2001 Man Booker Prize winning novel "Life of Pi", the protagonist, surviving shipwreck for months in a small boat, somehow avoids being eaten by the other survivor, a large Bengal tiger. The story was adapted in Ang Lee's 2012 feature


title: Tiger content: film of the same name. Jim Corbett's 1944 "Man-Eaters of Kumaon" tells ten true stories of his tiger-hunting exploits in what is now the northern Uttarakhand region of India. The book has sold over four million copies, and has been the basis of both fictional and documentary films. In Rudyard Kipling's 1894 "The Jungle Book", the tiger, Shere Khan, is the mortal enemy of the human protagonist, Mowgli. Other tiger characters aimed at children tend to be more benign, as for instance Tigger in A. A. Milne's Winnie-the-Pooh and Hobbes of the comic strip "Calvin and Hobbes", both of whom


title: Tiger content: are represented as simply stuffed animals come to life. Tigers are also mascots for various sports teams around the world. Tony the Tiger is a famous mascot for Kellogg's breakfast cereal Frosted Flakes. The Esso (Exxon) brand of petrol was advertised from 1969 onwards with the slogan 'put a tiger in your tank', and a tiger mascot; more than 2.5 million synthetic tiger tails were sold to motorists, who tied them to their petrol tank caps. The tiger appears in heraldry but is distinct from the heraldic beast tyger, a wolflike, snouted creature which has its roots in European Medieval


title: Tiger content: bestiaries. The tiger is one of the animals displayed on the Pashupati seal of the Indus Valley Civilisation. The tiger was the emblem of the Chola Dynasty and was depicted on coins, seals and banners. The seals of several Chola copper coins show the tiger, the Pandyan emblem fish and the Chera emblem bow, indicating that the Cholas had achieved political supremacy over the latter two dynasties. Gold coins found in Kavilayadavalli in the Nellore district of Andhra Pradesh have motifs of the tiger, bow and some indistinct marks. The tiger symbol of Chola Empire was later adopted by the


title: Tiger content: Liberation Tigers of Tamil Eelam and the tiger became a symbol of the unrecognised state of Tamil Eelam and Tamil independence movement. The Bengal tiger is the national animal of India and Bangladesh. The Malaysian tiger is the national animal of Malaysia. The Siberian tiger is the national animal of South Korea. Since the successful economies of South Korea, Taiwan, Hong Kong and Singapore were described as the Four Asian Tigers, a tiger economy is a metaphor for a nation in rapid development. A to Z Essays : Essay on Tiger Tiger The tiger ("Panthera tigris") is the largest cat


title: "Talk radio" content: United Kingdom is popular, though not as much as music radio. Nationwide talk stations include BBC Radio 4, BBC Radio 5 Live, BBC Radio 4 Extra and talkSPORT. Regional stations include BBC Radio Scotland and BBC Radio Wales. Many BBC Local Radio stations and some commercial stations offer a talk format, for example, BBC Radio London, the BBC's flagship local station. Other notable commercial talk stations include London's LBC which pioneered the newstalk format in Europe. LBC currently operates two services – LBC 97.3, a newstalk station on FM (London) and via several digital platforms nationally including DAB and Freeview;


title: "Tamil Nadu" content: the total poultry population in India. In 2003–2004, Tamil Nadu had produced 3783.6 million of eggs, which was the second highest in India representing 9.37 per cent of the total egg production in the country. With the second longest coastline in India, Tamil Nadu represented 27.54 per cent of the total value of fish and fishery products exported by India in 2006. Namakkal is also one of the major centres of egg production in India. Coimbatore is one of the major centres for poultry production. Tamil Nadu is one of the leading States in the textile sector and it houses


title: Troll content: Troll A troll is a class of being in Norse mythology and Scandinavian folklore. In Old Norse sources, beings described as trolls dwell in isolated rocks, mountains, or caves, live together in small family units, and are rarely helpful to human beings. Later, in Scandinavian folklore, trolls became beings in their own right, where they live far from human habitation, are not Christianized, and are considered dangerous to human beings. Depending on the source, their appearance varies greatly; trolls may be ugly and slow-witted, or look and behave exactly like human beings, with no particularly grotesque characteristic about them. Trolls


title: Troll content: are sometimes associated with particular landmarks, which at times may be explained as formed from a troll exposed to sunlight. Trolls are depicted in a variety of media in modern popular culture. The Old Norse nouns "troll" and "tröll" (variously meaning "fiend, demon, werewolf, jötunn") and Middle High German "troll, trolle" "fiend" (according to philologist Vladimir Orel likely borrowed from Old Norse) developed from Proto-Germanic neuter noun *"trullan". The origin of the Proto-Germanic word is unknown. Additionally, the Old Norse verb "trylla" 'to enchant, to turn into a troll' and the Middle High German verb "trüllen" "to flutter" both developed