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JFET

The junction gate field-effect transistor is one of the simplest types of field-effect transistor. JFETs are three-terminal semiconductor devices that can be used as electronically-controlled switches, amplifiers, or voltage-controlled resistors. Unlike bipolar transistors, JFETs are voltage-controlled in that they do not need a biasing current. Electric charge flows through a semiconducting channel between drain terminals. By applying a reverse bias voltage to a gate terminal, the channel is "pinched", so that the electric current is impeded or switched off completely. A JFET is ON when there is no voltage between its gate and source terminals. If a potential difference of the proper polarity is applied between its gate and source terminals, the JFET will be more resistive to current flow, which means less current would flow in the channel between the source and drain terminals. JFETs are sometimes referred to as depletion-mode devices as they rely on the principle of a depletion region, devoid of majority charge carriers.

JFETs can have an p-type channel. In the n-type, if the voltage applied to the gate is less than that applied to the source, the current will be reduced. A JFET has a large input impedance, which means that it has a negligible effect on external components or circuits connected to its gate. A succession of FET-like devices was patented by Julius Lilienfeld in the 1930s. However, materials science and fabrication technology would require decades of advances before FETs could be manufactured. JFET was first patented by Heinrich Welker in 1945. During 1940s, researchers John Bardeen, Walter Houser Brattain, William Shockley were trying to build a FET, but failed in their repeated attempts to make a FET, they discovered the point-contact transistor in the course of trying to diagnose the reasons for their failures. Following Shockley's theoretical treatment on JFET in 1952, a working practical JFET was made in 1953 by George F. Dacey and Ian M. Ross. Japanese engineers Jun-ichi Nishizawa and Y. Watanabe applied for a patent for a similar device in 1950 termed Static induction transistor.

The SIT is a type of JFET with a short channel length. The JFET is a long channel of semiconductor material, doped to contain an abundance of positive charge carriers or holes, or of negative carriers or electrons. Ohmic contacts at each end form the drain. A pn-junction is formed on one or both sides of the channel, or surrounding it, using a region with doping opposite to that of the channel, biased using an ohmic gate contact. JFET operation can be compared to that of a garden hose; the flow of water through a hose can be controlled by squeezing it to reduce the cross section and the flow of electric charge through a JFET is controlled by constricting the current-carrying channel. The current depends on the electric field between source and drain; this current dependency is not supported by the characteristics shown in the diagram above a certain applied voltage. This is the saturation region, the JFET is operated in this constant-current region where device current is unaffected by drain-source voltage.

The JFET shares this constant-current characteristic with junction transistors and with thermionic tube tetrodes and pentodes. Constriction of the conducting channel is accomplished using the field effect: a voltage between the gate and the source is applied to reverse bias the gate-source pn-junction, thereby widening the depletion layer of this junction, encroaching upon the conducting channel and restricting its cross-sectional area; the depletion layer is so-called because it is depleted of mobile carriers and so is electrically non-conducting for practical purposes. When the depletion layer spans the width of the conduction channel, pinch-off is achieved and drain-to-source conduction stops. Pinch-off occurs at a particular reverse bias of the gate-source junction; the pinch-off voltage varies even among devices of the same type. For example, VGS for the Temic J202 device varies from −0.8 V to −4 V. Typical values vary from −0.3 V to −10 V. To switch off an n-channel device requires a negative gate-source voltage.

Conversely, to switch off a p-channel device requires positive VGS. In normal operation, the electric field developed by the gate blocks source-drain conduction to some extent; some JFET devices are symmetrical with respect to the drain. The JFET gate is sometimes drawn in the middle of the channel; this symmetry suggests that "drain" and "source" are interchangeable, so the symbol should be used only for those JFETs where they are indeed interchangeable. The style of the symbol should show the component inside a circle; this is true in both the Europe. The symbol is drawn without the circle when drawing schematics of integrated circuits. More the symbol is drawn without its circle for discrete devices. In every case the arrow head shows the polarity of the P-N junction formed between the channel and the gate; as with an ordinary diode, the arrow points from P to N, the direction of conventional current when forward-biased. An English mnemonic is that the arrow of an N-channel device "points in".

At room temperature, JFET gate current is com

Aggravation (board game)

Aggravation is a board game for up to four players and versions for up to six players, whose object is to be the first player to have all four playing pieces reach the player's home section of the board. The game's name comes from the action of capturing an opponent's piece by landing on its space, known as "aggravating". Aggravation is one of the many variations of the game Pachisi, it was first produced in 1960 by CO-5 Company. Versions were made by Minneapolis-based Lakeside Industries, a division of Leisure Dynamic. Today, it is manufactured under license from Hasbro, its distinctive features are that the track accommodates from four to six players, unlike other Pachisi-like games which only allow four. There are no "safe" holes where a player's marbles cannot be captured other than the player's own base and home sections. Older versions of the game feature an asterisk-shaped board, symmetrical and identical in shape and size from all angles. In addition, older versions allowed up to four players instead of six.

However, modern versions of the game produced by Parker Brothers are made in an irregular pattern with a shape that varies for each player, though all players must travel an equal number of spaces in order to reach their respective home sections. The game starts with each player's placing four marbles in his/her "base". After the order of play is determined through the rolling of the die, each player rolls a single die on each turn to determine the number of spaces to move. All marbles remain in the base until either a 1 or 6 is rolled, which entitles the player to move a marble from the base to his/her "start", the first step before entering the track. While this is considered a turn, the move takes place in lieu of moving a marble that number of spaces, a six, if rolled, entitles a player to another turn whenever a legal move can be made; the winner is the first player. If playing partners when your partner has all their marbles in home they can roll to help get your marbles home faster, The hole in the center of the board is known as the "short cut".

A player, able to land a marble in this location by exact count has the option of taking a route faster to home. The short cut, has the drawback in that it may only be exited by rolling a 1. A player who lands a marble on a space occupied by an opponent's marble "aggravates" that player's piece and sends it back to that player's base. A player's piece may not be aggravated if it is on an inside corner as these are safe from aggravation. You must land on the space either after your opponent. Players are prohibited from passing their own marble. If this happens they can not move. If you rolled a 6 you may roll again. If playing teams, you can not pass your partner. If, there are multiple marbles, you can't jump over or aggravate a marble in the middle or front; the Unicorn Club has an annual season in which 30 games plus a series of two championship games are played. Rather than using a board with marbles, a replica of the board is used on a field; each color represents a team of 5 players. The four players take the place of marbles.

Each team has five home games during a season. Fans of each team, who are family and friends of the players, come to its home games and root for the team. Neutral officials are present at every game, making rulings in disputes. In team play, the following new rules are added: The team finishing first wins the game, but all teams are required to finish. The first-place finisher in the previous game gets three bonus rolls; the second-place finisher gets two, the third-place finisher gets one. Bonus rolls are used following the move of a player from the base to start with a 1, their use is required. The first-place finisher gets to start the following game first with a player on start rather than on the base; the order is always the same otherwise. The fifth-place finisher must wait until the first 4 teams have a player freed from the base before being allowed to start; the last place finisher must wait until all 5 other teams have started, at least one team has reached the home section. If a team has all its players sent back to start, it is considered as if it had freed a player for the purpose of allowing other teams to start.

A roll of 5 allows. This applies if it is another team's start; this move is known as a "Hi-Five". Teams have the tradition of holding a player in the start as long as possible and hoping for a Hi-Five; this is called "Hi-Five ready". Hi-Fives are used to get most players around the board. Moving onto another team's start is prohibited unless:That team's base is empty It is reached by a 6 There is no other possible legal move However, if a player manages to land there by any of the above methods, she or he may remain there as long as the team wishes; the super shortcut can not be used. It can only be accessed from the six spaces from one's own start. After five teams have finished, if the final team is unable to make a legal move in 6 consecutive rolls, or fails to finish within 6 rolls after bringing its final piece into home stretch (the last s

Jarrow

Jarrow is a town in north-east England, located on the River Tyne. Part of County Durham, in 1974 it became part of the metropolitan county of Tyne and Wear. In the eighth century, the monastery of Saint Paul in Jarrow was the home of Bede, regarded as the greatest Anglo-Saxon scholar and the father of English history. From the middle of the 19th century until 1935, Jarrow was a centre for shipbuilding, was the starting point of the Jarrow March against unemployment in 1936. Jarrow had a population of 43,431 in 2011; the Angles re-occupied a 1st-century Roman fort on the site of Jarrow in the 5th century. Its name is recorded around AD 750 as Gyruum, representing Old English Gyrwum = " the marsh dwellers", from Anglo-Saxon gyr = "mud", "marsh". Spellings are Jaruum in 1158, Jarwe in 1228. In the Northumbrian dialect it is known as Jarra; the Monastery of Paul of Tarsus in Jarrow, part of the twin foundation Monkwearmouth–Jarrow Abbey, was once the home of the Bede, whose most notable works include Ecclesiastical History of the English People and the translation of the Gospel of John into Old English.

Along with the abbey at Wearmouth, Jarrow became a center of learning and had the largest library north of the Alps due to the widespread travels of Benedict Biscop, its founder. In 794 Jarrow became the second target in England of the Vikings, who had plundered Lindisfarne in 793; the monastery was dissolved by Henry VIII. The ruins of the monastery are now associated with and built into the present-day church of St. Paul, which stands on the site. One wall of the church contains the oldest stained glass window in the world, dating from about AD 600. Just beside the monastery is "Jarrow Hall – Anglo-Saxon Farm and Bede Museum", a working museum dedicated to the life and times of Bede; this incorporates a grade II listed building and significant local landmark. A much under-publicised fact is that the world's oldest complete Bible, written in Latin to be presented to the Pope, was produced at this monastery – the Codex Amiatinus, it is safeguarded in the Laurentian Library, Italy. Three copies of the Bible were commissioned by Ceolfrid in 692.

This date has been established as the double monastery of Wearmouth-Jarrow secured a grant of additional land to raise the 2000 head of cattle needed to produce the vellum for the Bible's pages. Saint Ceolfrid accompanied one copy on its journey to be presented to Gregory II, but he died en route to Rome; the book appears in the 9th century in the Abbey of the Saviour, Monte Amiata in Tuscany, where it remained until 1786 when it passed to the Laurentian Library in Florence. Jarrow remained a small mid-Tyne town until the introduction of heavy industries such as coal mining and shipbuilding. Charles Mark Palmer established a shipyard – Palmer's Shipbuilding and Iron Company – in 1852 and became the first armour-plate manufacturer in the world. John Bowes, the first iron screw collier, revived the Tyne coal trade, Palmer's was responsible for the first modern cargo ship, as well as a number of notable warships. Around 1,000 ships were built at the yard, they produced small fishing boats to catch eel within the River Tyne, a delicacy at the time.

Palmer's employed as much as 80% of the town's working population until its closure in 1933 following purchase by National Shipbuilders Securities Ltd.. This organisation had been set up by Stanley Baldwin's Conservative government in the 1920s, but the first public statement had been made in 1930 whilst the Labour Party was in office; the aim of NSS was to reduce capacity within the British shipyards. In fact Palmer's yard was efficient and modern, but had serious financial problems; as from 1935, the sister ship of RMS Titanic, was demolished at Jarrow, being towed in 1937 to Inverkeithing, Scotland for final scrapping. The Great Depression brought so much hardship to Jarrow that the town was described by Life as "cursed." The closure of the shipyard was responsible for one of the events. Jarrow is marked in history as the starting point in 1936 of the Jarrow March to London to protest against unemployment in Britain. Jarrow MP Ellen Wilkinson wrote about these events in her book The Town; some doubt has been cast by historians as to how effective events such as the Jarrow March were but there is some evidence that they stimulated interest in regenerating'distressed areas'.

1938 saw the establishment of a ship-breaking yard and engineering works in the town, followed by the creation of a steelworks in 1939. The Jarrow rail disaster was a train collision that occurred on the 17 December 1915 at the Bede junction on a North Eastern Railway line; the collision was caused by seventeen people died in the collision. The Second World War revived the town's fortunes. After 1945 the shipbuilding industries were nationalised; the last shipyard in the town closed in 1980. Jarrow, in the year 1912, was the setting for the first of Monty Python's'Spanish Inquisition' sketches, one of the most well known and quoted sketches by the comedy troupe. In August 2014 a group of mothers from Darlington organised a march from Jarrow to London to oppose the privatisation of the NHS; the march took place in September 2014 and 3,000–5,000 people participated in the event. Jarrow's needs for secondary education are served by Jarrow School Springfield Comprehensive. Springfield was merged with another of Jarrow's secondary schools, Hedworthfield Comprehensive at Fellgate, followin

Zhuge

Zhuge in Chinese, Jegal in Korean, or Morokuzu in Japanese is a compound surname in East Asia. It is ranked 314th in Hundred Family Surnames in China; the surname has been synonymous with wisdom in Chinese culture, due to the fame of Zhuge Liang. According to the statistics, in 2018, there are around 16,000 Chinese people who have last names Zhuge. Zhuge Feng, Western Han dynasty official Zhuge Gui, Eastern Han dynasty official Zhuge Xuan, Zhuge Gui's cousin, Eastern Han dynasty official Zhuge Jin, Zhuge Gui's first son, Eastern Wu general of the Three Kingdoms period Zhuge Ke, Zhuge Jin's first son, Eastern Wu general and regent Zhuge Rong, Zhuge Jin's third son, Eastern Wu general Zhuge Liang, Zhuge Gui's second son, Shu Han statesman and military strategist of the Three Kingdoms period Zhuge Zhan, Zhuge Liang's son, Shu Han general Zhuge Shang, Zhuge Zhan's son, Shu Han military officer Zhuge Qiao, Zhuge Jin's second son and Zhuge Liang's adopted son, Shu Han official Zhuge Pan, Zhuge Qiao's son Zhuge Jun, Zhuge Gui's third son, Shu Han official Zhuge Dan, Zhuge Jin and Zhuge Liang's cousin, Cao Wei general of the Three Kingdoms period Zhuge Jing, Zhuge Dan's son, Western Jin dynasty official Zhuge Hui, Zhuge Jing's son, Western Jin dynasty official Zhuge Xu, Cao Wei official Zhuge Chong, Zhuge Xu's son, Western Jin dynasty official.

Zhuge Changmin, Eastern Jin dynasty general Zhuge Shuang, Tang dynasty general Jaegal Sung-yeol, former speed skater Morokuzu Nobuzumi, educator of the Meiji period Morokuzu Muneo, public policy professor at the University of Tokyo Zhuge Village Chinese surname history: Zhuge

Colijn de Coter

Colijn de Coter was an early Netherlandish painter who produced altarpieces. He worked in Brussels and Antwerp, his name was sometimes given as Colijn van Brusele, indicating that he hailed from Brussels or at the least lived there most of his active life. He signed several paintings with Coliin de Coter pingit me in Brabancia Bruselle. De Coter was born around 1440–1445; this can be deduced from a 1479 document in the Brussels archives, naming him as a husband and tenant of a house. Another document, dating from 1483, refers to him as Colijn van Brusele; this document states that he had registered with the Guild of Saint Luke in Antwerp and decorated a vault in the chapel of that guild in the Cathedral of Our Lady in Antwerp. The archives of the Brussels Brotherhood of Saint Eloy list three payments to Colijn de Coter in 1509–1511 for painting a church tabernacle. From the archives of this brotherhood, we can deduce that the painter's death fell somewhere in the period 1522–1532. Although unproven, art historians believe Colijn de Coter headed an influential workshop with a number of pupils.

This conclusion is based on the diversity in quality of the work attributed to him. The Leiden painter Cornelis Engebrechtsz. May have been one of his pupils. Contracts survive for two lost works by de Coter one dated 1493 for the decoration of a vault of a chapel and the other dated 1509–10 for the commission for the church tabernacle mentioned above. While the dates of these documents mark the known boundaries of his active period, his surviving work shows that this period more spanned from the years 1480 to 1525. Three signed paintings are known: St Luke Painting the Virgin in the parish church of Vieure, Cosne d’Allier, the altarpiece of the Trinity and the Virgin Crowned by Angels; these works are the basis for the attributions of other works to this artist. Some paintings attributed to Colijn de Coter are: Saint Lucas painting the Holy Virgin at the Church of St. Louis in Vieure; the painting shows model, while a carpenter is busy building the picture frame. Colijn de Coter is seen at work in his workshop.

Pruszcz Polyptych in the Parish Church in Pruszcz Gdański and in the National Museum in Warsaw, is a set of panels with history of Salvation and Old Testament's prefiguration of Redemption attributed to Colijn de Coter and his workshop. Saint Veronica, now at the Wallraf-Richartz-Museum in Cologne the right-side panel of a triptych; the lamentation of Christ, Amsterdam. The Family of King D. Manuel I of Portugal at the Fons Vitae, in the House of Misericórdia, in Porto. Saint Michael the Archangel and Saint Agnes, now at the Bob Jones University Museum & Gallery in Greenville The Holy Virgin with the Four Apostles and Saint Michael, now at the Royal Museums of Fine Arts of Belgium in Brussels, two fragments of an altarpiece of the Last Judgment commissioned for the main altar of the Church of St. Pantaleon in Cologne; the Johanna Van de Maerke Triptych or Descent from the Cross Altarpiece, now at the Royal Museums of Fine Arts of Belgium. Descent from the Cross, now in the Museo Regionale di Messina The Lamentation, now at the Chazen Museum of Art Rijkmuseum Amsterdam The Grove Dictionary of Art

Ruellia simplex

Ruellia simplex, the Mexican petunia, Mexican bluebell or Britton's wild petunia, is a species of flowering plant in the family Acanthaceae. It is a native of Mexico, the Caribbean, South America, it has become a widespread invasive plant in Florida, where it was introduced as an ornamental before 1933. Ruellia simplex is an evergreen perennial growing 3 ft tall, forming colonies of stalks with lance-shaped leaves that are 6 to 12 in and.5 to.75 in wide. Trumpet shaped flowers are metallic blue to purple, with five petals, 3 in wide. There is a dwarf variety, only 1 ft tall. "Ruellia simplex C. Wright" is the oldest and accepted name for this species, variously called Ruellia angustifolia Lindau, Ruellia brittoniana Leonard, Cryphiacanthus angustifolius Nees, among several synonyms; the genus is named after French botanist Jean Ruel, while the specific name refers to the simple, not compound leaves. Ruellia simplex in Florida. Atlas of Florida Vascular Plants. IPNI Listing