document_title: Clock

question_text: who built the first standing clock in england and when

question_tokens: who built the first standing clock in england and when

text: Clock

text: History[edit]

text: Time-measuring devices[edit]

text: Sundials[edit]

text: The apparent position of the Sun in the sky moves over the course of each day, reflecting the rotation of the Earth. Shadows cast by stationary objects move correspondingly, so their positions can be used to indicate the time of day. A sundial shows the time by displaying the position of a shadow on a (usually) flat surface, which has markings that correspond to the hours.[7] Sundials can be horizontal, vertical, or in other orientations. Sundials were widely used in ancient times.[8] With the knowledge of latitude, a well-constructed sundial can measure local solar time with reasonable accuracy, within a minute or two. Sundials continued to be used to monitor the performance of clocks until the modern era.[citation needed] However, practical limitations, such as that sundials only work well on relatively clear days, and never during the night, encouraged the development of other techniques for measuring and displaying time. The Jantar Mantar At Delhi and Jaipur are examples of sundials. They were built by Maharaja Jai Singh II.

text: Devices that measure duration, elapsed time and/or intervals[edit]

text: Many devices can be used to mark passage of time without respect to reference time (time of day, minutes, etc.) and can be useful for measuring duration and/or intervals. Examples of such duration timers are, candle clocks, incense clocks and the hourglass. Both the candle clock and the incense clock work on the same principle wherein the consumption of resources is more or less constant allowing reasonably precise, and repeatable, estimates of time passages. In the hourglass, fine sand pouring through a tiny hole at a constant rate indicates an arbitrary, predetermined, passage of time, the resource is not consumed but re-used.

text: Water[edit]

text: Water clocks, also known as clepsydrae (sg: clepsydra), along with the sundials, are possibly the oldest time-measuring instruments, with the only exceptions being the vertical gnomon and the day counting tally stick.[9] Given their great antiquity, where and when they first existed is not known and perhaps unknowable. The bowl-shaped outflow is the simplest form of a water clock and is known to have existed in Babylon and in Egypt around the 16th century BC. Other regions of the world, including India and China, also have early evidence of water clocks, but the earliest dates are less certain. Some authors, however, write about water clocks appearing as early as 4000 BC in these regions of the world.[10]

text: Greek astronomer Andronicus of Cyrrhus supervised the construction of the Tower of the Winds in Athens in the 1st century B.C.[11] The Greek and Roman civilizations are credited for initially advancing water clock design to include complex gearing, which was connected to fanciful automata and also resulted in improved accuracy. These advances were passed on through Byzantium and Islamic times, eventually making their way back to Europe. Independently, the Chinese developed their own advanced water clocks（水鐘）in 725 A.D., passing their ideas on to Korea and Japan.

text: Some water clock designs were developed independently and some knowledge was transferred through the spread of trade. Pre-modern societies do not have the same precise timekeeping requirements that exist in modern industrial societies, where every hour of work or rest is monitored, and work may start or finish at any time regardless of external conditions. Instead, water clocks in ancient societies were used mainly for astrological reasons. These early water clocks were calibrated with a sundial. While never reaching the level of accuracy of a modern timepiece, the water clock was the most accurate and commonly used timekeeping device for millennia, until it was replaced by the more accurate pendulum clock in 17th-century Europe.

text: Islamic civilization is credited with further advancing the accuracy of clocks with elaborate engineering. In 797 (or possibly 801), the Abbasid caliph of Baghdad, Harun al-Rashid, presented Charlemagne with an Asian Elephant named Abul-Abbas together with a "particularly elaborate example" of a water[12] clock. Pope Sylvester II introduced clocks to northern and western Europe around 1000AD[13]

text: In the 13th century, Al-Jazari, an engineer from Mesopotamia (lived 1136–1206) who worked for Artuqid king of Diyar-Bakr, Nasir al-Din, made numerous clocks of all shapes and sizes. A book on his work described 50 mechanical devices in 6 categories, including water clocks. The most reputed clocks included the Elephant, Scribe and Castle clocks, all of which have been successfully reconstructed. As well as telling the time, these grand clocks were symbols of status, grandeur and wealth of the Urtuq State.[citation needed]

text: Early mechanical[edit]

text: This section needs attention from an expert in Time. See the talk page for details. WikiProject Time may be able to help recruit an expert. (August 2016)

text: The word horologia (from the Greek ὡρα, hour, and λέγειν, to tell) was used to describe early mechanical clocks,[15] but the use of this word (still used in several Romance languages) [16] for all timekeepers conceals the true nature of the mechanisms. For example, there is a record that in 1176 Sens Cathedral installed a ‘horologe’[17] but the mechanism used is unknown. According to Jocelin of Brakelond, in 1198 during a fire at the abbey of St Edmundsbury (now Bury St Edmunds), the monks 'ran to the clock' to fetch water, indicating that their water clock had a reservoir large enough to help extinguish the occasional fire.[18] The word clock (from the Celtic words clocca and clogan, both meaning "bell"), which gradually supersedes "horologe", suggests that it was the sound of bells which also characterized the prototype mechanical clocks that appeared during the 13th century in Europe.

text: A water-powered cogwheel clock was created in China in AD 725 by Yi Xing and Liang Lingzan. This is not considered an escapement mechanism clock as it was unidirectional, the Song dynasty polymath and genius Su Song (1020–1101) incorporated it into his monumental innovation of the astronomical clock-tower of Kaifeng in 1088.[19][page needed] His astronomical clock and rotating armillary sphere still relied on the use of either flowing water during the spring, summer, autumn seasons and liquid mercury during the freezing temperature of winter (i.e. hydraulics). A mercury clock, described in the Libros del saber, a Spanish work from 1277 consisting of translations and paraphrases of Arabic works, is sometimes quoted as evidence for Muslim knowledge of a mechanical clock. A mercury-powered cogwheel clock was created by Ibn Khalaf al-Muradi[20][21]

text: In Europe, between 1280 and 1320, there is an increase in the number of references to clocks and horologes in church records, and this probably indicates that a new type of clock mechanism had been devised. Existing clock mechanisms that used water power were being adapted to take their driving power from falling weights. This power was controlled by some form of oscillating mechanism, probably derived from existing bell-ringing or alarm devices. This controlled release of power—the escapement—marks the beginning of the true mechanical clock, which differed from the previously mentioned cogwheel clocks. Verge escapement mechanism derived in the surge of true mechanical clocks, which didn't need any kind of fluid power, like water or mercury, to work.

text: These mechanical clocks were intended for two main purposes: for signalling and notification (e.g. the timing of services and public events), and for modeling the solar system. The former purpose is administrative, the latter arises naturally given the scholarly interests in astronomy, science, astrology, and how these subjects integrated with the religious philosophy of the time. The astrolabe was used both by astronomers and astrologers, and it was natural to apply a clockwork drive to the rotating plate to produce a working model of the solar system.

text: Simple clocks intended mainly for notification were installed in towers, and did not always require faces or hands. They would have announced the canonical hours or intervals between set times of prayer. Canonical hours varied in length as the times of sunrise and sunset shifted. The more sophisticated astronomical clocks would have had moving dials or hands, and would have shown the time in various time systems, including Italian hours, canonical hours, and time as measured by astronomers at the time. Both styles of clock started acquiring extravagant features such as automata.

text: In 1283, a large clock was installed at Dunstable Priory; its location above the rood screen suggests that it was not a water clock.[citation needed] In 1292, Canterbury Cathedral installed a 'great horloge'. Over the next 30 years there are mentions of clocks at a number of ecclesiastical institutions in England, Italy, and France. In 1322, a new clock was installed in Norwich, an expensive replacement for an earlier clock installed in 1273. This had a large (2 metre) astronomical dial with automata and bells. The costs of the installation included the full-time employment of two clockkeepers for two years.[citation needed]

text: Astronomical[edit]

text: Besides the Chinese astronomical clock of Su Song in 1088 mentioned above, in Europe there were the clocks constructed by Richard of Wallingford in St Albans by 1336, and by Giovanni de Dondi in Padua from 1348 to 1364. They no longer exist, but detailed descriptions of their design and construction survive,[22][23] and modern reproductions have been made.[23] They illustrate how quickly the theory of the mechanical clock had been translated into practical constructions, and also that one of the many impulses to their development had been the desire of astronomers to investigate celestial phenomena.

text: Wallingford's clock had a large astrolabe-type dial, showing the sun, the moon's age, phase, and node, a star map, and possibly the planets. In addition, it had a wheel of fortune and an indicator of the state of the tide at London Bridge. Bells rang every hour, the number of strokes indicating the time.[22] Dondi's clock was a seven-sided construction, 1 metre high, with dials showing the time of day, including minutes, the motions of all the known planets, an automatic calendar of fixed and movable feasts, and an eclipse prediction hand rotating once every 18 years.[23] It is not known how accurate or reliable these clocks would have been. They were probably adjusted manually every day to compensate for errors caused by wear and imprecise manufacture. Water clocks are sometimes still used today, and can be examined in places such as ancient castles and museums. The Salisbury Cathedral clock, built in 1386, is considered to be the world's oldest surviving mechanical clock that strikes the hours.[24]

text: Spring-driven[edit]

text: Clockmakers developed their art in various ways. Building smaller clocks was a technical challenge, as was improving accuracy and reliability. Clocks could be impressive showpieces to demonstrate skilled craftsmanship, or less expensive, mass-produced items for domestic use. The escapement in particular was an important factor affecting the clock's accuracy, so many different mechanisms were tried.

text: Spring-driven clocks appeared during the 15th century,[25][26][27] although they are often erroneously credited to Nuremberg watchmaker Peter Henlein (or Henle, or Hele) around 1511.[28][29][30] The earliest existing spring driven clock is the chamber clock given to Phillip the Good, Duke of Burgundy, around 1430, now in the Germanisches Nationalmuseum.[6] Spring power presented clockmakers with a new problem: how to keep the clock movement running at a constant rate as the spring ran down. This resulted in the invention of the stackfreed and the fusee in the 15th century, and many other innovations, down to the invention of the modern going barrel in 1760.

text: Early clock dials did not indicate minutes and seconds. A clock with a dial indicating minutes was illustrated in a 1475 manuscript by Paulus Almanus,[31] and some 15th-century clocks in Germany indicated minutes and seconds.[32] An early record of a seconds hand on a clock dates back to about 1560 on a clock now in the Fremersdorf collection.[33]:417–418[34]

text: During the 15th and 16th centuries, clockmaking flourished, particularly in the metalworking towns of Nuremberg and Augsburg, and in Blois, France. Some of the more basic table clocks have only one time-keeping hand, with the dial between the hour markers being divided into four equal parts making the clocks readable to the nearest 15 minutes. Other clocks were exhibitions of craftsmanship and skill, incorporating astronomical indicators and musical movements. The cross-beat escapement was invented in 1584 by Jost Bürgi, who also developed the remontoire. Bürgi's clocks were a great improvement in accuracy as they were correct to within a minute a day.[35][36] These clocks helped the 16th-century astronomer Tycho Brahe to observe astronomical events with much greater precision than before.[citation needed][how?]

text: Pendulum[edit]

text: The next development in accuracy occurred after 1656 with the invention of the pendulum clock. Galileo had the idea to use a swinging bob to regulate the motion of a time-telling device earlier in the 17th century. Christiaan Huygens, however, is usually credited as the inventor. He determined the mathematical formula that related pendulum length to time (about 99.4 cm or 39.1 inches for the one second movement) and had the first pendulum-driven clock made. The first model clock was built in 1657 in the Hague, but it was in England that the idea was taken up.[38] The longcase clock (also known as the grandfather clock) was created to house the pendulum and works by the English clockmaker William Clement in 1670 or 1671. It was also at this time that clock cases began to be made of wood and clock faces to utilize enamel as well as hand-painted ceramics.

text: In 1670, William Clement created the anchor escapement,[39] an improvement over Huygens' crown escapement. Clement also introduced the pendulum suspension spring in 1671. The concentric minute hand was added to the clock by Daniel Quare, a London clockmaker and others, and the second hand was first introduced.

text: Hairspring[edit]

text: In 1675, Huygens and Robert Hooke invented the spiral balance, or the hairspring, designed to control the oscillating speed of the balance wheel. This crucial advance finally made accurate pocket watches possible. The great English clockmaker, Thomas Tompion, was one of the first to use this mechanism successfully in his pocket watches, and he adopted the minute hand which, after a variety of designs were trialled, eventually stabilised into the modern-day configuration.[40] The Rev. Edward Barlow invented the rack and snail striking mechanism for striking clocks, which was a great improvement over the previous mechanism. The repeating clock, that chimes the number of hours (or even minutes) was invented by either Quare or Barlow in 1676. George Graham invented the deadbeat escapement for clocks in 1720.

text: Marine chronometer[edit]

text: A major stimulus to improving the accuracy and reliability of clocks was the importance of precise time-keeping for navigation. The position of a ship at sea could be determined with reasonable accuracy if a navigator could refer to a clock that lost or gained less than about 10 seconds per day. This clock could not contain a pendulum, which would be virtually useless on a rocking ship. In 1714, the British government offered large financial rewards to the value of 20,000 pounds,[42] for anyone who could determine longitude accurately. John Harrison, who dedicated his life to improving the accuracy of his clocks, later received considerable sums under the Longitude Act.

text: In 1735, Harrison built his first chronometer, which he steadily improved on over the next thirty years before submitting it for examination. The clock had many innovations, including the use of bearings to reduce friction, weighted balances to compensate for the ship's pitch and roll in the sea and the use of two different metals to reduce the problem of expansion from heat. The chronometer was tested in 1761 by Harrison's son and by the end of 10 weeks the clock was in error by less than 5 seconds.[43]

text: Mass production[edit]

text: The British had predominated in watch manufacture for much of the 17th and 18th centuries, but maintained a system of production that was geared towards high quality products for the elite.[44] Although there was an attempt to modernise clock manufacture with mass production techniques and the application of duplicating tools and machinery by the British Watch Company in 1843, it was in the United States that this system took off. In 1816, Eli Terry and some other Connecticut clockmakers developed a way of mass-producing clocks by using interchangeable parts.[45] Aaron Lufkin Dennison started a factory in 1851 in Massachusetts that also used interchangeable parts, and by 1861 was running a successful enterprise incorporated as the Waltham Watch Company.[46][47]

text: Early electric[edit]

text: In 1815, Francis Ronalds published the first electric clock powered by dry pile batteries.[48] Alexander Bain, Scottish clockmaker, patented the electric clock in 1840. The electric clock's mainspring is wound either with an electric motor or with an electromagnet and armature. In 1841, he first patented the electromagnetic pendulum. By the end of the nineteenth century, the advent of the dry cell battery made it feasible to use electric power in clocks. Spring or weight driven clocks that use electricity, either alternating current (AC) or direct current (DC), to rewind the spring or raise the weight of a mechanical clock would be classified as an electromechanical clock. This classification would also apply to clocks that employ an electrical impulse to propel the pendulum. In electromechanical clocks the electricity serves no time keeping function. These types of clocks were made as individual timepieces but more commonly used in synchronized time installations in schools, businesses, factories, railroads and government facilities as a master clock and slave clocks.

text: Electric clocks that are powered from the AC supply often use synchronous motors. The supply current alternates with a frequency of 50 hertz in many countries, and 60 hertz in others. The rotor of the motor rotates at a speed that is related to the alternation frequency. Appropriate gearing converts this rotation speed to the correct ones for the hands of the analog clock. The development of electronics in the 20th century led to clocks with no clockwork parts at all. Time in these cases is measured in several ways, such as by the alternation of the AC supply, vibration of a tuning fork, the behaviour of quartz crystals, or the quantum vibrations of atoms. Electronic circuits divide these high-frequency oscillations to slower ones that drive the time display. Even mechanical clocks have since come to be largely powered by batteries, removing the need for winding.

text: Quartz[edit]

text: The piezoelectric properties of crystalline quartz were discovered by Jacques and Pierre Curie in 1880.[49][50] The first crystal oscillator was invented in 1917 by Alexander M. Nicholson after which, the first quartz crystal oscillator was built by Walter G. Cady in 1921.[4] In 1927 the first quartz clock was built by Warren Marrison and J. W. Horton at Bell Telephone Laboratories in Canada.[51][4] The following decades saw the development of quartz clocks as precision time measurement devices in laboratory settings—the bulky and delicate counting electronics, built with vacuum tubes, limited their practical use elsewhere. The National Bureau of Standards (now NIST) based the time standard of the United States on quartz clocks from late 1929 until the 1960s, when it changed to atomic clocks.[52] In 1969, Seiko produced the world's first quartz wristwatch, the Astron.[53] Their inherent accuracy and low cost of production resulted in the subsequent proliferation of quartz clocks and watches.[49]

text: Atomic[edit]

text: As of the 2010s, atomic clocks are the most accurate clocks in existence. They are considerably more accurate than quartz clocks as they can be accurate to within a few seconds over thousands of years.[54] Atomic clocks were first theorized by Lord Kelvin in 1879.[55] In the 1930s the development of Magnetic resonance created practical method for doing this.[56] A prototype ammonia maser device was built in 1949 at the U.S. National Bureau of Standards (NBS, now NIST). Although it was less accurate than existing quartz clocks, it served to demonstrate the concept.[57][58][59] The first accurate atomic clock, a caesium standard based on a certain transition of the caesium-133 atom, was built by Louis Essen in 1955 at the National Physical Laboratory in the UK.[60] Calibration of the caesium standard atomic clock was carried out by the use of the astronomical time scale ephemeris time (ET).[61] As of 2013, the most stable atomic clocks are ytterbium clocks, which are stable to within less than two parts in 1 quintillion (6982200000000000000♠2×10−18).[62]

text: Operation[edit]

text: The invention of the mechanical clock in the 13th century initiated a change in timekeeping methods from continuous processes, such as the motion of the gnomon's shadow on a sundial or the flow of liquid in a water clock, to periodic oscillatory processes, such as the swing of a pendulum or the vibration of a quartz crystal,[5][63] which had the potential for more accuracy. All modern clocks use oscillation.

text: Although the mechanisms they use vary, all oscillating clocks, mechanical, digital and atomic, work similarly and can be divided into analogous parts.[64][65][66] They consist of an object that repeats the same motion over and over again, an oscillator, with a precisely constant time interval between each repetition, or 'beat'. Attached to the oscillator is a controller device, which sustains the oscillator's motion by replacing the energy it loses to friction, and converts its oscillations into a series of pulses. The pulses are then counted by some type of counter, and the number of counts is converted into convenient units, usually seconds, minutes, hours, etc. Finally some kind of indicator displays the result in human readable form.

text: Power source[edit]

text: This provides power to keep the clock going.

text:
In mechanical clocks, the power source is typically either a weight suspended from a cord or chain wrapped around a pulley, sprocket or drum; or a spiral spring called a mainspring. Mechanical clocks must be wound periodically, usually by turning a knob or key or by pulling on the free end of the chain, to store energy in the weight or spring to keep the clock running.
In electric clocks, the power source is either a battery or the AC power line. In clocks that use AC power, a small backup battery is often included to keep the clock running if it is unplugged temporarily from the wall or during a power outage. Battery powered analog wall clocks are available that operate over 15 years between battery changes.

text: Oscillator[edit]

text: The timekeeping element in every modern clock is a harmonic oscillator, a physical object (resonator) that vibrates or oscillates repetitively at a precisely constant frequency.[4]

text:
In mechanical clocks, this is either a pendulum or a balance wheel.
In some early electronic clocks and watches such as the Accutron, it is a tuning fork.
In quartz clocks and watches, it is a quartz crystal.
In atomic clocks, it is the vibration of electrons in atoms as they emit microwaves.
In early mechanical clocks before 1657, it was a crude balance wheel or foliot which was not a harmonic oscillator because it lacked a balance spring. As a result, they were very inaccurate, with errors of perhaps an hour a day.[67]

text: The advantage of a harmonic oscillator over other forms of oscillator is that it employs resonance to vibrate at a precise natural resonant frequency or 'beat' dependent only on its physical characteristics, and resists vibrating at other rates. The possible precision achievable by a harmonic oscillator is measured by a parameter called its Q,[68][69] or quality factor, which increases (other things being equal) with its resonant frequency.[70] This is why there has been a long term trend toward higher frequency oscillators in clocks. Balance wheels and pendulums always include a means of adjusting the rate of the timepiece. Quartz timepieces sometimes include a rate screw that adjusts a capacitor for that purpose. Atomic clocks are primary standards, and their rate cannot be adjusted.

text: Synchronized or slave clocks[edit]

text: Some clocks rely for their accuracy on an external oscillator; that is, they are automatically synchronized to a more accurate clock:

text:
Slave clocks, used in large institutions and schools from the 1860s to the 1970s, kept time with a pendulum, but were wired to a master clock in the building, and periodically received a signal to synchronize them with the master, often on the hour.[71] Later versions without pendulums were triggered by a pulse from the master clock and certain sequences used to force rapid synchronization following a power failure.
Synchronous electric clocks do not have an internal oscillator, but count cycles of the 50 or 60 Hz oscillation of the AC power line, which is synchronized by the utility to a precision oscillator. The counting may be done electronically, usually in clocks with digital displays, or, in analog clocks, the AC may drive a synchronous motor which rotates an exact fraction of a revolution for every cycle of the line voltage, and drives the gear train. Although changes in the grid line frequency due to load variations may cause the clock to temporarily gain or lose several seconds during the course of a day, the total number of cycles per 24 hours is maintained extremely accurately by the utility company, so that the clock keeps time accurately over long periods.
Computer real time clocks keep time with a quartz crystal, but can be periodically (usually weekly) synchronized over the Internet to atomic clocks (UTC), using the Network Time Protocol (NTP). Sometimes computers on a local area network (LAN) get their time from a single local server which is maintained accurately.
Radio clocks keep time with a quartz crystal, but are periodically synchronized to time signals transmitted from dedicated standard time radio stations or satellite navigation signals, which are set by atomic clocks.

text: Controller[edit]

text: This has the dual function of keeping the oscillator running by giving it 'pushes' to replace the energy lost to friction, and converting its vibrations into a series of pulses that serve to measure the time.

text:
In mechanical clocks, this is the escapement, which gives precise pushes to the swinging pendulum or balance wheel, and releases one gear tooth of the escape wheel at each swing, allowing all the clock's wheels to move forward a fixed amount with each swing.
In electronic clocks this is an electronic oscillator circuit that gives the vibrating quartz crystal or tuning fork tiny 'pushes', and generates a series of electrical pulses, one for each vibration of the crystal, which is called the clock signal.
In atomic clocks the controller is an evacuated microwave cavity attached to a microwave oscillator controlled by a microprocessor. A thin gas of cesium atoms is released into the cavity where they are exposed to microwaves. A laser measures how many atoms have absorbed the microwaves, and an electronic feedback control system called a phase-locked loop tunes the microwave oscillator until it is at the frequency that causes the atoms to vibrate and absorb the microwaves. Then the microwave signal is divided by digital counters to become the clock signal.[72]

text: In mechanical clocks, the low Q of the balance wheel or pendulum oscillator made them very sensitive to the disturbing effect of the impulses of the escapement, so the escapement had a great effect on the accuracy of the clock, and many escapement designs were tried. The higher Q of resonators in electronic clocks makes them relatively insensitive to the disturbing effects of the drive power, so the driving oscillator circuit is a much less critical component.[4]

text: Counter chain[edit]

text: This counts the pulses and adds them up to get traditional time units of seconds, minutes, hours, etc. It usually has a provision for setting the clock by manually entering the correct time into the counter.

text:
In mechanical clocks this is done mechanically by a gear train, known as the wheel train. The gear train also has a second function; to transmit mechanical power from the power source to run the oscillator. There is a friction coupling called the 'cannon pinion' between the gears driving the hands and the rest of the clock, allowing the hands to be turned to set the time.[73]
In digital clocks a series of integrated circuit counters or dividers add the pulses up digitally, using binary logic. Often pushbuttons on the case allow the hour and minute counters to be incremented and decremented to set the time.

text: Indicator[edit]

text: This displays the count of seconds, minutes, hours, etc. in a human readable form.

text:
The earliest mechanical clocks in the 13th century didn't have a visual indicator and signalled the time audibly by striking bells. Many clocks to this day are striking clocks which strike the hour.
Analog clocks display time with an analog clock face, which consists of a round dial with the numbers 1 through 12, the hours in the day, around the outside. The hours are indicated with an hour hand, which makes two revolutions in a day, while the minutes are indicated by a minute hand, which makes one revolution per hour. In mechanical clocks a gear train drives the hands; in electronic clocks the circuit produces pulses every second which drive a stepper motor and gear train, which move the hands.
Digital clocks display the time in periodically changing digits on a digital display. A common misconception is that a digital clock is more accurate than an analog wall clock, but the indicator type is separate and apart from the accuracy of the timing source.
Talking clocks and the speaking clock services provided by telephone companies speak the time audibly, using either recorded or digitally synthesized voices.

text: Types[edit]

text: Clocks can be classified by the type of time display, as well as by the method of timekeeping.

text: Time display methods[edit]

text: Analog[edit]

text: Analog clocks usually use a clock face which indicates time using rotating pointers called "hands" on a fixed numbered dial or dials. The standard clock face, known universally throughout the world, has a short "hour hand" which indicates the hour on a circular dial of 12 hours, making two revolutions per day, and a longer "minute hand" which indicates the minutes in the current hour on the same dial, which is also divided into 60 minutes. It may also have a "second hand" which indicates the seconds in the current minute. The only other widely used clock face today is the 24 hour analog dial, because of the use of 24 hour time in military organizations and timetables. Before the modern clock face was standardized during the Industrial Revolution, many other face designs were used throughout the years, including dials divided into 6, 8, 10, and 24 hours. During the French Revolution the French government tried to introduce a 10-hour clock, as part of their the decimal-based metric system of measurement, but it didn't catch on. An Italian 6 hour clock was developed in the 18th century, presumably to save power (a clock or watch striking 24 times uses more power).

text: Another type of analog clock is the sundial, which tracks the sun continuously, registering the time by the shadow position of its gnomon. Because the sun does not adjust to daylight savings times, users must add an hour during that time. Corrections must also be made for the equation of time, and for the difference between the longitudes of the sundial and of the central meridian of the time zone that is being used (i.e. 15 degrees east of the prime meridian for each hour that the time zone is ahead of GMT). Sundials use some or part of the 24 hour analog dial. There also exist clocks which use a digital display despite having an analog mechanism—these are commonly referred to as flip clocks. Alternative systems have been proposed. For example, the "Twelv" clock indicates the current hour using one of twelve colors, and indicates the minute by showing a proportion of a circular disk, similar to a moon phase.[74]

text: Digital[edit]

text:
Examples of digital clocks

Digital clock outside Kanazawa Station displaying the time by controlling valves on a fountain

Basic digital clock radio

Mobile phone display with an analog-style clock (albeit generated by a digital computer) in the middle, and a digital-style in the top right corner

Diagram of a mechanical digital display of a flip clock

text: Digital clocks display a numeric representation of time. Two numeric display formats are commonly used on digital clocks:

text:
the 24-hour notation with hours ranging 00–23;
the 12-hour notation with AM/PM indicator, with hours indicated as 12AM, followed by 1AM–11AM, followed by 12PM, followed by 1PM–11PM (a notation mostly used in domestic environments).

text: Most digital clocks use electronic mechanisms and LCD, LED, or VFD displays; many other display technologies are used as well (cathode ray tubes, nixie tubes, etc.). After a reset, battery change or power failure, these clocks without a backup battery or capacitor either start counting from 12:00, or stay at 12:00, often with blinking digits indicating that the time needs to be set. Some newer clocks will reset themselves based on radio or Internet time servers that are tuned to national atomic clocks. Since the advent of digital clocks in the 1960s, the use of analog clocks has declined significantly.

text: Some clocks, called 'flip clocks', have digital displays that work mechanically. The digits are painted on sheets of material which are mounted like the pages of a book. Once a minute, a page is turned over to reveal the next digit. These displays are usually easier to read in brightly lit conditions than LCDs or LEDs. Also, they do not go back to 12:00 after a power interruption. Flip clocks generally do not have electronic mechanisms. Usually, they are driven by AC-synchronous motors.

text: Hybrid (analog-digital)[edit]

text: Clocks with analog quadrants, with a digital component, usually minutes and hours displayed analogously and seconds displayed in digital mode.

text: Auditory[edit]

text: For convenience, distance, telephony or blindness, auditory clocks present the time as sounds. The sound is either spoken natural language, (e.g. "The time is twelve thirty-five"), or as auditory codes (e.g. number of sequential bell rings on the hour represents the number of the hour like the bell, Big Ben). Most telecommunication companies also provide a speaking clock service as well.

text: Word[edit]

text: Word clocks are clocks that display the time visually using sentences. E.g.: "It’s about three o’clock." These clocks can be implemented in hardware or software.

text: Projection[edit]

text: Some clocks, usually digital ones, include an optical projector that shines a magnified image of the time display onto a screen or onto a surface such as an indoor ceiling or wall. The digits are large enough to be easily read, without using glasses, by persons with moderately imperfect vision, so the clocks are convenient for use in their bedrooms. Usually, the timekeeping circuitry has a battery as a backup source for an uninterrupted power supply to keep the clock on time, while the projection light only works when the unit is connected to an A.C. supply. Completely battery-powered portable versions resembling flashlights are also available.

text: Tactile[edit]

text: Auditory and projection clocks can be used by people who are blind or have limited vision. There are also clocks for the blind that have displays that can be read by using the sense of touch. Some of these are similar to normal analog displays, but are constructed so the hands can be felt without damaging them. Another type is essentially digital, and uses devices that use a code such as Braille to show the digits so that they can be felt with the fingertips.

text: Multi-display[edit]

text: Some clocks have several displays driven by a single mechanism, and some others have several completely separate mechanisms in a single case. Clocks in public places often have several faces visible from different directions, so that the clock can be read from anywhere in the vicinity. Of course, all the faces show the same time. Other clocks show the current time in several time-zones. Watches that are intended to be carried by travellers often have two displays, one for the local time and the other for the time at home, which is useful for making pre-arranged phone calls. Some equation clocks have two displays, one showing mean time and the other solar time, as would be shown by a sundial. Some clocks have both analog and digital displays. Clocks with Braille displays usually also have conventional digits so they can be read by sighted people.

text: Purposes[edit]

text: Clocks are in homes, offices and many other places; smaller ones (watches) are carried on the wrist or in a pocket; larger ones are in public places, e.g. a railway station or church. A small clock is often shown in a corner of computer displays, mobile phones and many MP3 players.

text: The primary purpose of a clock is to display the time. Clocks may also have the facility to make a loud alert signal at a specified time, typically to waken a sleeper at a preset time; they are referred to as alarm clocks. The alarm may start at a low volume and become louder, or have the facility to be switched off for a few minutes then resume. Alarm clocks with visible indicators are sometimes used to indicate to children too young to read the time that the time for sleep has finished; they are sometimes called training clocks.

text: A clock mechanism may be used to control a device according to time, e.g. a central heating system, a VCR, or a time bomb (see: digital counter). Such mechanisms are usually called timers. Clock mechanisms are also used to drive devices such as solar trackers and astronomical telescopes, which have to turn at accurately controlled speeds to counteract the rotation of the Earth.

text: Most digital computers depend on an internal signal at constant frequency to synchronize processing; this is referred to as a clock signal. (A few research projects are developing CPUs based on asynchronous circuits.) Some equipment, including computers, also maintains time and date for use as required; this is referred to as time-of-day clock, and is distinct from the system clock signal, although possibly based on counting its cycles.

text: Time standards[edit]

text: For some scientific work timing of the utmost accuracy is essential. It is also necessary to have a standard of the maximum accuracy against which working clocks can be calibrated. An ideal clock would give the time to unlimited accuracy, but this is of course not realisable. Many physical processes, in particular including some transitions between atomic energy levels, occur at exceedingly stable frequency; counting cycles of such a process can give a very accurate and consistent time—clocks which work this way are usually called atomic clocks. Such clocks are typically large, very expensive, require a controlled environment, and are far more accurate than required for most purposes; they are typically used in a standards laboratory.

text: Navigation[edit]

text: Until advances in the late twentieth century, navigation depended on the ability to measure latitude and longitude. Latitude can be determined through celestial navigation; the measurement of longitude requires accurate knowledge of time. This need was a major motivation for the development of accurate mechanical clocks. John Harrison created the first highly accurate marine chronometer in the mid-18th century. The Noon gun in Cape Town still fires an accurate signal to allow ships to check their chronometers. Many buildings near major ports used to have (some still do) a large ball mounted on a tower or mast arranged to drop at a pre-determined time, for the same purpose. While satellite navigation systems such as the Global Positioning System (GPS) require unprecedentedly accurate knowledge of time, this is supplied by equipment on the satellites; vehicles no longer need timekeeping equipment.

text: Specific types[edit]

text:
By mechanism
By function
By style

Astronomical clock
Atomic clock
Candle clock
Congreve clock
Conical pendulum clock
Digital clock
Electric clock
Flip clock
Hourglass
Incense clock
Mechanical watch
Oil-lamp clock
Pendulum clock
Pipe organ clock
Projection clock
Pulsar clock
Quantum clock
Quartz clock
Radio clock
Rolling ball clock
Spring drive watch
Steam clock
Sundial
Torsion pendulum clock
Water clock

10-hour clock
Alarm clock
Binary clock
Chiming clock
Chronometer watch
Cuckoo clock
Equation clock
Game clock
Japanese clock
Master clock
Musical clock
Railroad chronometer
Slave clock
Speaking clock
Stopwatch
Striking clock
Talking clock
Tide clock
Time ball
Time clock
World clock

American clock
Automaton clock
Balloon clock
Banjo clock
Bracket clock
Carriage clock
Cartel clock
Cat clock
Chariot clock
Clock tower
Cuckoo clock
Doll's head clock
Floral clock
French Empire mantel clock
Granddaughter clock
Grandfather clock
Grandmother clock
Lantern clock
Lighthouse clock
Longcase (Tall-case) clock
Mantel clock
Skeleton clock
Tower clock
Turret clock
Watch


document_title: Madagascar: Escape 2 Africa

question_text: who did bernie mac play in madagascar 2

question_tokens: who did bernie mac play in madagascar 2

root

text: Madagascar: Escape 2 Africa

text: Plot

text: In Africa, Zuba the lion tries to teach his son Alakay how to fight, but the cub is more interested in dancing. Rival male Makunga challenges Zuba for the title of alpha lion, and during their fight Alakay is captured by poachers. The crate containing Alakay falls into the ocean and drifts to New York City, where he is renamed Alex and grows up at the Central Park Zoo with Marty the zebra, Melman the giraffe, and Gloria the hippopotamus.

tag: p

text: Years later, following their adventure in Madagascar, the zoo animals—Alex, Marty, Melman, Gloria, the penguins Skipper, Kowalski, Rico, and Private, and chimpanzees Mason and Phil—prepare to return to New York aboard a battered airplane piloted by the penguins, accompanied by the lemurs King Julian, Maurice, and Mort. The plane runs out of fuel and crash lands in continental Africa. The animals find themselves at a watering hole on a nature reserve, and are excited to meet others of their species. Alex is reunited with his parents and impresses them with tales of his status as "the king of New York". Marty fits in with a herd of other zebras who look and sound just like him. Melman, a hypochondriac, is distressed that the reserve has no doctors, so the other giraffes appoint him their witch doctor. Seeking romance, Gloria attracts the attention of the smooth-talking male hippo Moto Moto.

text: Meanwhile, the penguins set about repairing the plane, assisted by numerous chimpanzees recruited by Mason and Phil. They steal vehicles from several groups of New Yorkers who are on safari and strip them for parts. Nana, a tough old woman who slapped Alex around during the events of Madagascar, takes charge of the stranded tourists and helps them survive in the wilderness.

text: The zoo animals' excitement soon turns to disappointment. In a scheme to oust Zuba as alpha lion, Makunga insists that Alex complete a rite of passage which Alex mistakes for a talent contest. It is actually a fighting contest, and Makunga tricks him into choosing the strongest lion as his opponent, resulting in Alex's humiliating defeat. Faced with the duty of banishing his son, Zuba relinquishes his title as alpha and Makunga takes over. Meanwhile, Marty is dejected by the realization that the other zebras can do everything he can, believing himself no longer unique. Melman comes to believe that he is deathly ill, and Gloria's interest in Moto Moto saddens him since he has secretly loved her for a long time. The four friends argue heatedly with one another. Gloria has a date with Moto Moto, but loses interest when she realizes he is only attracted to her because of her size. After a pep talk from King Julian, Melman finally reveals his feelings for Gloria.

text: The next day, the animals panic when the watering hole dries up. Determined to redeem himself, Alex mends his friendship with Marty and they leave the reserve to investigate upriver. King Julien suggests that offering a sacrifice to the nearby volcano will restore the water. Melman, forlorn and believing he is dying, volunteers to be sacrificed. Gloria stops him from jumping into the volcano, and realizes that he is the perfect guy for her. Alex and Marty discover that the stranded New Yorkers have built a camp and dammed up the river, and Alex is captured by them. Zuba rushes to his aid, but Alex saves them both by dancing for the tourists, who remember him fondly from the zoo. Marty, Melman, Gloria, the penguins, and the chimpanzees arrive in the repaired airplane and help Alex destroy the dam, restoring the water. Makunga angrily makes a stand for control, but Alex tricks him into being subdued by Nana. Zuba offers Alex the title of alpha lion, but he declines, and father and son become co-leaders.

text: Skipper the penguin marries a bobblehead doll from the plane, and he, the other penguins, and the chimpanzees head off to honeymoon in Monte Carlo. Alex, Marty, Melman, Gloria, and the lemurs happily decide to stay on the reserve for a while.

text: Cast

text:
Ben Stiller as Alex the lion
Chris Rock as Marty the zebra, as well as the other zebras in the herd
David Schwimmer as Melman the giraffe
Jada Pinkett Smith as Gloria the hippopotamus
Sacha Baron Cohen as King Julien the ring-tailed lemur
Cedric the Entertainer as Maurice the aye-aye
Andy Richter as Mort, a Goodman's mouse lemur
Bernie Mac as Zuba, Alex's father
Sherri Shepherd as Alex's mother
Alec Baldwin as Makunga the lion
Elisa Gabrielli as Nana
will.i.am as Moto Moto the hippopotamus
Tom McGrath as Skipper the penguin
Chris Miller as Kowalski the penguin
Christopher Knights as Private the penguin
John DiMaggio as Rico the penguin
Conrad Vernon as Mason the chimpanzee (Phil, the other main chimpanzee, is unvoiced)
Fred Tatasciore as Teetsi the lion and as one of the poachers who captures Alakay
Eric Darnell as Joe the giraffe and as one of the poachers who captures Alakay
Al Roker as a newscaster
Stephen Kearin as Stephen the giraffe, as a rhinoceros, and as one of the New Yorkers
Danny Jacobs as one of the New Yorkers
Dan O'Connor as an African buffalo and as one of the New Yorkers
Stacy Ferguson as a female hippopotamus
Harland Williams as a giraffe
Bridget Hoffman as one of the New Yorkers
Quinn Dempsey Stiller, Ben Stiller's son, as baby Alex
Declan Swift also as baby Alex
Thomas Stanley as baby Marty
Zachary Gordon as baby Melman
Willow Smith as baby Gloria
David P. Smith as Bobby the dik-dik
Conner Rayburn as a young giraffe
John Eric Bentley provided additional voices

tag: ul

text: Production

text: A sequel to Madagascar had been in development since 2005, when the first film had been released, with a release date planned for late 2008.[5] In the first teaser trailer, which was released in March 2008, the film was subtitled with The Crate Escape.[6] By June 2008, the film was given its final title — Escape 2 Africa.[7]

text: Reception

text: Critical response

text: The film received generally mixed to positive reviews from critics. Rotten Tomatoes reported that 64% of critics gave the film a positive review, based on 150 reviews, with the consensus view that the film was "an improvement on the original, with more fleshed-out characters, crisper animation and more consistent humor," and with an average rating of 5.9/10.[8] Another review aggregator, Metacritic classified the film into the "generally favorable reviews" category with 61/100 approval rating based on 25 reviews, also a bit higher a score than the original.[9]

text: Michael Phillips of the Chicago Tribune stated in his review that the film "goes easy on the pop culture jokes, I should clarify: one of the smarter things in the script is how Alex, who digs his Bob Fosse and Jerome Robbins dance moves, becomes the film's primary pop-cult gag."[10] Roger Ebert of the Chicago Sun-Times gave the film 3 stars and wrote "This is a brighter, more engaging film than the original Madagascar.[11] Steven D. Greydanus complained the film's plot was similar to The Lion King, Joe Versus the Volcano, and Happy Feet.[12] Carrie Rickey of The Philadelphia Inquirer gave the film 2 stars and wrote "Take the flat tire that was Madagascar. Retread it with The Lion King storyline. Pump it up with air. Now you have Madagascar: Escape 2 Africa."[13] John Anderson gave the film 3½ approval rating and stated "Madagascar 2: Escape to Africa, the sequel to the enormously successful DreamWorks adventure and a film that hews close to the whole Lion King/species-as-destiny/self-fulfillment paradigm."[14]

text: Box office

text: On its opening day, the film grossed $17,555,027 from 4,056 theaters with an $4,328 average. It went to be at #1 at the box office with $63,106,589 with $15,559 average per theater.[15] As of March 19, 2009, it achieved a gross of $180,010,950 (29.8% of total gross) in the United States and Canada along with a gross of $423,889,404 (70.2%) in other regions adding to a worldwide gross total of $603,900,354.[1]

text: Accolades

text: Broadcast Film Critics:

text: Best Animated Film (nominated)

text: Nickelodeon Kids' Choice Awards 2009

text: Favorite Animated Film[3]

text: Soundtrack

text:
Madagascar: Escape 2 Africa: Motion Picture Soundtrack

Soundtrack album by Various artists

Released
November 8, 2008 (2008-11-08)

Genre
Pop rock
Reggaeton
Rap

Label
Interscope

tag: table

text:
No.
Title
Performer(s)
Length

1.
"Once Upon A Time In Africa"
Hans Zimmer
3:44

2.
"The Traveling Song"
will.i.am
3:25

3.
"Party! Party! Party!"
Hans Zimmer
3:31

4.
"I Like to Move It"
will.i.am
3:41

5.
"The Good, the Bad and the Ugly (Polka Version)"
Hans Zimmer
0:54

6.
"Big and Chunky"
will.i.am
3:21

7.
"Chums"
Heitor Pereira
2:15

8.
"New York, New York (Polka Version)"
Hans Zimmer
1:30

9.
"Volcano"
Hans Zimmer
2:49

10.
"Rescue Me"
Hans Zimmer
3:36

11.
"More than a Feeling"
Boston
4:45

12.
"She Loves Me"
will.i.am
1:45

13.
"Foofie"
Hans Zimmer
2:39

14.
"Copacabana (At the Copa)"
Barry Manilow
4:06

15.
"Monochromatic Friends"
Hans Zimmer
3:02

16.
"Best Friends"
will.i.am
2:25

17.
"Alex On The Spot"
Hans Zimmer and will.i.am
1:58

Total length:
49:26

text: Enhanced Videos

text:
No.
Title
Performer(s)
Length

1.
"I Like to Move It"
will.i.am

2.
"She Loves Me by"
will.i.am

3.
"Big and Chunky (DVD only)"
will.i.am

text: Home media

text: Madagascar: Escape 2 Africa was released on DVD and Blu-ray Disc on February 6, 2009, along with two episodes from The Penguins of Madagascar series: "Popcorn Panic" and "Gone in a Flash".[16] In the first week at the DVD sales chart, Madagascar opened at #1, selling 1,681,938 units which translated to $27.09m in revenue.[17] As per the latest figures, 7,060,997 units have been sold, bringing in $102,791,511 in revenue. This does not include Blu-ray sales/DVD rentals.[17]

text: Video game

text: A video game based on the film was made for the Xbox 360, PlayStation 3, Wii, PlayStation 2, Microsoft Windows, and Nintendo DS,[18] and released on November 4, 2008, in North America.[19] The video game's gameplay is similar to the first movie's video game with the same characters and moves, although the environment is set in Africa.[20]

text: Sequel

text: A sequel titled Madagascar 3: Europe's Most Wanted was released on June 8, 2012. Alex the Lion, Marty the Zebra, Gloria the Hippo, and Melman the Giraffe are still fighting to get home to New York. This time their journey takes them to a traveling circus in Europe which they will reinvent Madagascar style.

text: Notes

text: ^ In July 2014, the film's distribution rights were purchased by DreamWorks Animation from Paramount Pictures.[21]

tag: ol


document_title: Cartagena Film Festival

question_text: which is the main purpose of the cartagena film festival

text: Cartagena Film Festival

text:
Cartagena Film Festival

Cartagena Film Festival office

Location
Cartagena, Colombia

Founded
1959

Awards
Golden India Catalina

Website
www.ficcifestival.com

text: The Cartagena Film Festival (Spanish: Festival Internacional de Cine de Cartagena de Indias), or FICCI, is a film festival held in Cartagena, Colombia, which focuses mainly on the promotion of Colombian television series, Latin American films and short films. The Cartagena Film Festival, which is held every March, is the oldest film festival in Latin America.[1]

text: The Cartagena Film Festival was founded 1959 by Victor Nieto.[1] Nieto remained the director of the film festival for 48 years, his last being in 2008.[1] Nieto died at the age of 92 in November 2008.[1] Lina Paola Rodriguez was appointed manager by Nieto in 2007 and 2008, and will remain acting director following Nieto's death.[1]

text: Best Film winners[edit]

text:
Year
Film
Director
Country

1962
O Pagador de Promessas
Anselmo Duarte
 Brazil

1969
El dependiente
Leonardo Favio
 Argentina

1972
Juan Lamaglia y señora
Raúl de la Torre
 Argentina

1973
Espejismo
Armando Robles Godoy
 Peru

1974
Los siete locos
Leopoldo Torre Nilsson
 Argentina

1976
Furtivos
José Luis Borau
 Spain

1977
Cantata de Chile
Humberto Solás
 Cuba

1979
El pez que fuma
Román Chalbaud
 Venezuela

1980
El otro Francisco
Sergio Giral
 Cuba

1985
Oriana
Fina Torres
 Venezuela,  France

1986
Visa USA
Lisandro Duque Naranjo
 Colombia,  Cuba

1990
La Tigra
Camilo Luzuriaga
 Ecuador

1991
Yo, la peor de todas
María Luisa Bemberg
 Argentina

1992
Tacones lejanos
Pedro Almodóvar
 Spain,  France

1993
O Corpo
José Antonio Garcia
 Brazil

1994
La madre muerta
Ana Álvarez
 Spain

1998
Bajo bandera
Juan José Jusid
 Argentina,  Italy

2000
Garage Olimpo
Marco Bechis
 Argentina,  Italy,  France

Orfeu
Carlos Diegues
 Brazil

2001
Eu Tu Eles
Andrucha Waddington
 Brazil

2002
Lavoura Arcaica
Luiz Fernando Carvalho
 Brazil

2003
Cidade de Deus
Fernando Meirelles
 Brazil

2004
Carandiru
Héctor Babenco
 Brazil,  Argentina,  Italy

2005
Sumas y restas
Víctor Gaviria
 Colombia,  Spain

2006
La última luna
Miguel Littín
 Mexico,  Spain,  Chile

2007
La edad de la peseta
Pavel Giroud
 Cuba,  Spain,  Venezuela

2008
Maldeamores
Carlitos Ruiz Ruiz, Mariem Pérez Riera
 Puerto Rico,  USA

2009
Lake Tahoe
Fernando Eimbcke
 Mexico,  Japan,  USA

2010
Gigante
Adrián Biniez
 Uruguay,  Argentina,  Germany,  Spain,  Netherlands

2011
Post Mortem
Pablo Larraín
 Chile,  Germany,  Mexico

2012
El estudiante
Santiago Mitre
 Argentina

2013
Tabu
Miguel Gomes
 Portugal

2014
Tierra en la lengua
Rubén Mendoza
 Colombia

2015
Ixcanul
Jayro Bustamante
 Guatemala

2016
Neon Bull
Gabriel Mascaro
 Brazil

2017
Aquarius
Kleber Mendonça Filho
 Brazil


document_title: Hell in a Cell

question_text: who has won the most hell in a cell matches

text: Hell in a Cell

text: History[edit]

text: The original concept for the Hell in a Cell structure was created by Jim Cornette. As detailed in the Kayfabe Commentaries release "Timeline of WWE: 1997", Cornette described this concept as a combination of a cage which surrounded the majority of the ringside area (this was a cage design which was popular in Memphis wrestling promotions), and the cage used in both the NWA (National Wrestling Aliance) and WCW (World Championship Wrestling) for their WarGames matches (which had a top on the cage). On an October 2015 video podcast, Vince Russo said Cornette probably did come up with the concept, but the name "Hell in a Cell" came from him.[1]

text: The Hell in a Cell match was first introduced at WWF Badd Blood on October 5, 1997 at the Kiel Center, now known as Scottrade Center, in St. Louis, Missouri. The background to the inaugural match was built on Undertaker's loss to Bret Hart two months prior at the 1997 SummerSlam in a WWF World Heavyweight Championship match which Shawn Michaels was assigned to referee. Michaels had deliberately interjected himself in the match and cost The Undertaker a win which resulted in a match between the two at In Your House: Ground Zero. That match was ruled a no-contest due to the two bypassing and attacking the officials. As a climatic end to the feud, their following bout was originally scheduled to be held as a steel cage match. However, instead of a normal cage enclosing only the ring, a larger roofed structure was constructed, enclosing not only the ring but also the surrounding ringside area. The wider space between the ring apron and the cell walls allowed for entering and exiting the ring. At Badd Blood, Michaels defeated The Undertaker, (with interference from The Undertaker's debuting brother Kane) and won the number-one contendership to the WWF World Heavyweight Championship. The cage's size also makes the use of weapons possible as well. Wrestlers usually use weapons in Hell in a Cell by taking them from under the ring.

text: Hell in a Cell matches are rare in WWE as it is designed to be the climax to certain feuds. There have only been thirty six such matches in WWE, 33 of which have been broadcast on pay-per-view events due to the logistical difficulty in setting them up and its perception as a special attraction due to the nature of the match. In 2009, WWE presented its first pay-per-view event to specifically feature the Hell in a Cell for its marquee matches. Despite the match's profile, prior to the first self-titled Hell in a Cell pay-per-view event, championships were defended six times out of sixteen of the Hell in a Cell matches. The first time a title was defended in the match was at the 2000 No Way Out with Triple H retaining the WWF Championship in the sixth Hell in a Cell match. The longest Hell in a Cell match was held at Bad Blood 2004 between Triple H and Shawn Michaels at over 47 minutes. The first time a title changed hands in a Hell in a Cell match was in 2009, when The Undertaker won the World Heavyweight Championship from CM Punk. The Undertaker has been involved in the most Hell in a Cell matches having competed in fourteen and has the record for most victories at eight. Only two matches have been broadcast on television, both in 1998 on Raw is War. The Hell in a Cell match on the June 15th edition of Raw is War between Stone Cold and Undertaker vs. Kane and Mankind ended with Stone Cold and Undertaker beating Kane and Mankind after Raw is War went off the air. On the August 24th edition of Raw is War, Mankind fought his tag team partner at the time, Kane in a Hell in a Cell match. This match went to a no contest after Stone Cold Steve Austin interfered and assaulted Kane. Then when Undertaker tried to break inside the cell to help his brother, Mr. McMahon raised the cell and made Undertaker and Stone Cold wait to get their hands on each other until Summerslam. The match has appeared at WWE's flagship event, WrestleMania, three times (WrestleMania XV, XXVIII and 32).

text: Other appearances and variations[edit]

text: The structure itself has made four additional appearances, although WWE does not consider them to be Hell in a Cell matches. The first was when the Cell lowered over the ring while Kane fought Stone Cold Steve Austin in a first-ever First Blood match for the WWF Championship at King of the Ring '98. The second featured Big Boss Man challenging Al Snow for the WWF Hardcore Championship in a Kennel from Hell match at Unforgiven '99. The match consisted of a standard steel cage with the cell placed atop it, and the object was to escape from both the cage and cell while trying to avoid guard dogs that were placed between the ring and cell door. Snow, the first competitor to escape the steel cage and the cell, was declared the winner. The third time was on the September 28, 2009 episode of Raw, during a gauntlet match with John Cena against Chris Jericho, The Big Show, and Randy Orton. The cell was lowered after Cena defeated Jericho and Big Show by Disqualification, when Orton's turn came. Cena ordered the cell to be lowered, and then Cena brawled Orton on top of the structure. The match was declared a no contest. The fourth time was on the October 20, 2014 episode of Raw, when the Hell in a Cell structure was lowered, on orders from Kane, during a handicap street fight involving Kane, Randy Orton, and Seth Rollins and John Cena and Dean Ambrose, which Kane, Orton and Rollins won.

text: In WCW, The Hell in a Cell match is seen as the structural successor to the Thundercage (originally called the Caged Heat match) match type seen in WCW, which was virtually identical in basic construction; however, thundercage was rarely used by World Championship Wrestling (WCW) and thus fans had little to no knowledge of its existence. The Thundercage actually precedes Hell in a Cell by roughly two and a half years, as the Thundercage was used in the match between Ric Flair and Big Van Vader for the WCW World Heavyweight Championship in February 1994 at SuperBrawl IV. It was also used in matches between Sting and The Great Muta.

text: List of Hell in a Cell matches[edit]

text: Dallas holds the record for hosting the most Hell in a Cell matches with five. Four were held in Dallas proper and one in the western suburb of Arlington.

text: In second place is Miami, which has hosted four Hell in a Cell matches with three in Miami proper and one in the suburb of Miami Gardens. In third place is Newark and Boston, both of which have hosted three Hell in a Cell matches.

text:
Number
Match
Stipulations
Event
Date
Location
Length

1
Shawn Michaels defeated The Undertaker
Singles Hell in a Cell to determine the #1 contender for the WWF Championship at Survivor Series
Badd Blood
October 5, 1997
St. Louis, Missouri
29:55

2
The Undertaker and Stone Cold Steve Austin defeated Mankind and Kane
Tornado Tag Team Hell in a Cell
Raw Is War
June 15, 1998
San Antonio, Texas
10:38

3
The Undertaker defeated Mankind
Singles Hell in a Cell
King of the Ring
June 28, 1998
Pittsburgh, Pennsylvania
17:10

4
Mankind vs. Kane ended in a no contest
Singles Hell in a Cell
Raw Is War
August 24, 1998
Philadelphia, Pennsylvania
7:41

5
The Undertaker defeated Big Boss Man
Singles Hell in a Cell
WrestleMania XV
March 28, 1999
Philadelphia, Pennsylvania
9:48

6
Triple H (c) defeated Cactus Jack
Singles Hell in a Cell for the WWF Championship. If Cactus Jack lost, he would have to retire as an active wrestler in the WWF.
No Way Out
February 27, 2000
Hartford, Connecticut
23:57

7
Kurt Angle (c) defeated The Undertaker, Triple H, Stone Cold Steve Austin, Rikishi and The Rock
Six-man Hell in a Cell for the WWF Championship
Armageddon
December 10, 2000
Birmingham, Alabama
32:12

8
Triple H defeated Chris Jericho
Singles Hell in a Cell
Judgment Day
May 19, 2002
Nashville, Tennessee
24:06

9
Brock Lesnar (c) defeated The Undertaker
Singles Hell in a Cell for the WWE Championship
No Mercy
October 20, 2002
North Little Rock, Arkansas
27:18

10
Triple H (c) defeated Kevin Nash
Singles Hell in a Cell for the World Heavyweight Championship with special guest referee Mick Foley
Bad Blood
June 15, 2003
Houston, Texas
21:01

11
Triple H defeated Shawn Michaels
Singles Hell in a Cell
Bad Blood
June 13, 2004
Columbus, Ohio
47:26

12
Batista (c) defeated Triple H
Singles Hell in a Cell for the World Heavyweight Championship
Vengeance
June 26, 2005
Las Vegas, Nevada
26:54

13
The Undertaker defeated Randy Orton
Singles Hell in a Cell
Armageddon
December 18, 2005
Providence, Rhode Island
30:31

14
D-Generation X (Triple H and Shawn Michaels) defeated Mr. McMahon, Shane McMahon and Big Show
2-on-3 Handicap Hell in a Cell. This also marked the debut of the "amplified" version of the cell
Unforgiven
September 17, 2006
Toronto, Ontario, Canada
25:04

15
Batista (c) defeated The Undertaker
Singles Hell in a Cell for the World Heavyweight Championship
Survivor Series
November 18, 2007
Miami, Florida
21:24

16
The Undertaker defeated Edge
Singles Hell in a Cell
SummerSlam
August 17, 2008
Indianapolis, Indiana
26:43

17
The Undertaker defeated CM Punk (c)
Singles Hell in a Cell for the World Heavyweight Championship
Hell in a Cell
October 4, 2009
Newark, New Jersey
10:24

18
Randy Orton defeated John Cena (c)
Singles Hell in a Cell for the WWE Championship
21:24

19
D-Generation X (Triple H and Shawn Michaels) defeated Legacy (Cody Rhodes and Ted DiBiase)
Tornado Tag Team Hell in a Cell
17:48

20
Randy Orton (c) defeated Sheamus
Singles Hell in a Cell for the WWE Championship
Hell in a Cell
October 3, 2010
Dallas, Texas
22:51

21
Kane (c) defeated The Undertaker
Singles Hell in a Cell for the World Heavyweight Championship
21:38

22
John Cena (c) defeated Alberto Del Rio, CM Punk, Dolph Ziggler and Jack Swagger
Five-Man Hell in a Cell for the WWE Championship
Raw (Dark Match)
September 26, 2011
Kansas City, Missouri
5:01

23
Mark Henry (c) defeated Randy Orton
Singles Hell in a Cell for the World Heavyweight Championship
Hell in a Cell
October 2, 2011
New Orleans, Louisiana
15:54

24
Alberto Del Rio defeated John Cena (c) and CM Punk
Triple Threat Hell in a Cell for the WWE Championship
24:07

25
The Undertaker defeated Triple H
Singles Hell in a Cell with special guest referee Shawn Michaels
WrestleMania XXVIII
April 1, 2012
Miami Gardens, Florida
30:52

26
CM Punk (c) defeated Ryback
Singles Hell in a Cell for the WWE Championship
Hell in a Cell
October 28, 2012
Atlanta, Georgia
11:22

27
CM Punk defeated Ryback and Paul Heyman
2-on-1 Handicap Hell in a Cell
Hell in a Cell
October 27, 2013
Miami, Florida
13:48

28
Randy Orton defeated Daniel Bryan
Singles Hell in a Cell for the vacant WWE Championship with special guest referee Shawn Michaels
22:07

29
John Cena defeated Randy Orton
Singles Hell in a Cell to determine the #1 contender for the WWE World Heavyweight Championship
Hell in a Cell
October 26, 2014
Dallas, Texas
25:52

30
Seth Rollins defeated Dean Ambrose
Singles Hell in a Cell
14:00

31
Roman Reigns defeated Bray Wyatt
Singles Hell in a Cell
Hell in a Cell
October 25, 2015
Los Angeles, California
23:08

32
Brock Lesnar defeated The Undertaker
Singles Hell in a Cell
22:10

33
The Undertaker defeated Shane McMahon
Singles Hell in a Cell. If Shane McMahon wins, he gains control of Raw and Undertaker will be barred from competing at WrestleMania again
WrestleMania 32
April 3, 2016
Arlington, Texas
30:08

34
Roman Reigns (c) defeated Rusev
Singles Hell in a Cell for the WWE United States Championship
Hell in a Cell
October 30, 2016
Boston, Massachusetts
24:35

35
Kevin Owens (c) defeated Seth Rollins
Singles Hell in a Cell for the WWE Universal Championship
23:15

36
Charlotte Flair defeated Sasha Banks (c)
Singles Hell in a Cell for the WWE Raw Women's Championship
22:25

37
Kevin Owens vs. Shane McMahon
Singles Hell in a Cell
Hell in a Cell
October 8, 2017
Detroit, Michigan

text: Participant list[edit]

text:
Wrestler
Victories
Appearances

The Undertaker
8
14

Triple H
6
9

Shawn Michaels
3
4

Randy Orton
3
6

Batista
2
2

Brock Lesnar
2
2

Roman Reigns
2
2

John Cena
2
4

CM Punk
2
5

Kurt Angle
1
1

Mark Henry
1
1

Kevin Owens
1
1

Charlotte Flair
1
1

Stone Cold Steve Austin
1
2

Alberto Del Rio
1
2

Seth Rollins
1
2

Kane
1
3

Big Boss Man
0
1

Rikishi
0
1

The Rock
0
1

Chris Jericho
0
1

Kevin Nash
0
1

Mr. McMahon
0
1

Big Show
0
1

Edge
0
1

Cody Rhodes
0
1

Ted DiBiase
0
1

Sheamus
0
1

Dolph Ziggler
0
1

Jack Swagger
0
1

Paul Heyman
0
1

Daniel Bryan
0
1

Dean Ambrose
0
1

Bray Wyatt
0
1

Rusev
0
1

Sasha Banks
0
1

Ryback
0
2

Shane McMahon
0
2

Mick Foley
0
4


document_title: p–n junction

question_text: what is built in potential of pn junction

text: p–n junction

text: Properties[edit]

text: The p–n junction possesses essential properties for modern electronics. A p-doped semiconductor is relatively conductive. The same is true of an n-doped semiconductor, but the junction between them can become depleted of charge carriers, and hence non-conductive, depending on the relative voltages of the two semiconductor regions. By manipulating this non-conductive layer, p–n junctions are commonly used as diodes: circuit elements that allow a flow of electricity in one direction but not in the other (opposite) direction. Bias is the application of a voltage across a p–n junction; forward bias is in the direction of easy current flow, and reverse bias is in the direction of little or no current flow.

text: The forward-bias and the reverse-bias properties of the p–n junction imply that it can be used as a diode. A p–n junction diode allows electric charges to flow in one direction, but not in the opposite direction; negative charges (electrons) can easily flow through the junction from n to p but not from p to n, and the reverse is true for holes. When the p–n junction is forward-biased, electric charge flows freely due to reduced resistance of the p–n junction. When the p–n junction is reverse-biased, however, the junction barrier (and therefore resistance) becomes greater and charge flow is minimal.

text: Equilibrium (zero bias)[edit]

text:
In a p–n junction, without an external applied voltage, an equilibrium condition is reached in which a potential difference is formed across the junction. This potential difference is called built-in potential

V

b
i

{\displaystyle V_{\rm {bi}}}

.

text: After joining p-type and n-type semiconductors, electrons from the n region near the p–n interface tend to diffuse into the p region leaving behind positively charged ions in the n region and being recombined with holes, forming negatively charged ions in the p region. Likewise, holes from the p-type region near the p–n interface begin to diffuse into the n-type region, leaving behind negatively charged ions in the p region and recombining with electrons, forming positive ions in the n region[further explanation needed]. The regions near the p–n interface lose their neutrality and most of their mobile carriers, forming the space charge region or depletion layer (see figure A).

text: The electric field created by the space charge region opposes the diffusion process for both electrons and holes. There are two concurrent phenomena: the diffusion process that tends to generate more space charge, and the electric field generated by the space charge that tends to counteract the diffusion. The carrier concentration profile at equilibrium is shown in figure A with blue and red lines. Also shown are the two counterbalancing phenomena that establish equilibrium.

text: The space charge region is a zone with a net charge provided by the fixed ions (donors or acceptors) that have been left uncovered by majority carrier diffusion. When equilibrium is reached, the charge density is approximated by the displayed step function. In fact, since the y-axis of figure A is log-scale, the region is almost completely depleted of majority carriers (leaving a charge density equal to the net doping level), and the edge between the space charge region and the neutral region is quite sharp (see figure B, Q(x) graph). The space charge region has the same magnitude of charge on both sides of the p–n interfaces, thus it extends farther on the less doped side in this example (the n side in figures A and B).

text: Forward bias[edit]

text: In forward bias, the p-type is connected with the positive terminal and the n-type is connected with the negative terminal.

text: With a battery connected this way, the holes in the p-type region and the electrons in the n-type region are pushed toward the junction and start to neutralize the depletion zone, reducing its width. The positive potential applied to the p-type material repels the holes, while the negative potential applied to the n-type material repels the electrons. The change in potential between the p side and the n side decreases or switches sign. With increasing forward-bias voltage, the depletion zone eventually becomes thin enough that the zone's electric field cannot counteract charge carrier motion across the p–n junction, which as a consequence reduces electrical resistance. The electrons that cross the p–n junction into the p-type material (or holes that cross into the n-type material) will diffuse into the nearby neutral region. The amount of minority diffusion in the near-neutral zones determines the amount of current that may flow through the diode.

text: Only majority carriers (electrons in n-type material or holes in p-type) can flow through a semiconductor for a macroscopic length. With this in mind, consider the flow of electrons across the junction. The forward bias causes a force on the electrons pushing them from the N side toward the P side. With forward bias, the depletion region is narrow enough that electrons can cross the junction and inject into the p-type material. However, they do not continue to flow through the p-type material indefinitely, because it is energetically favorable for them to recombine with holes. The average length an electron travels through the p-type material before recombining is called the diffusion length, and it is typically on the order of micrometers.[1]

text: Although the electrons penetrate only a short distance into the p-type material, the electric current continues uninterrupted, because holes (the majority carriers) begin to flow in the opposite direction. The total current (the sum of the electron and hole currents) is constant in space, because any variation would cause charge buildup over time (this is Kirchhoff's current law). The flow of holes from the p-type region into the n-type region is exactly analogous to the flow of electrons from N to P (electrons and holes swap roles and the signs of all currents and voltages are reversed).

text: Therefore, the macroscopic picture of the current flow through the diode involves electrons flowing through the n-type region toward the junction, holes flowing through the p-type region in the opposite direction toward the junction, and the two species of carriers constantly recombining in the vicinity of the junction. The electrons and holes travel in opposite directions, but they also have opposite charges, so the overall current is in the same direction on both sides of the diode, as required.

text: The Shockley diode equation models the forward-bias operational characteristics of a p–n junction outside the avalanche (reverse-biased conducting) region.

text: Reverse bias[edit]

text: Connecting the p-type region to the negative terminal of the battery and the n-type region to the positive terminal corresponds to reverse bias. If a diode is reverse-biased, the voltage at the cathode is comparatively higher than at the anode. Therefore, very little current will flow until the diode breaks down. The connections are illustrated in the adjacent diagram.

text: Because the p-type material is now connected to the negative terminal of the power supply, the 'holes' in the p-type material are pulled away from the junction, leaving behind charged ions and causing the width of the depletion region to increase. Likewise, because the n-type region is connected to the positive terminal, the electrons will also be pulled away from the junction, with similar effect. This increases the voltage barrier causing a high resistance to the flow of charge carriers, thus allowing minimal electric current to cross the p–n junction. The increase in resistance of the p–n junction results in the junction behaving as an insulator.

text: The strength of the depletion zone electric field increases as the reverse-bias voltage increases. Once the electric field intensity increases beyond a critical level, the p–n junction depletion zone breaks down and current begins to flow, usually by either the Zener or the avalanche breakdown processes. Both of these breakdown processes are non-destructive and are reversible, as long as the amount of current flowing does not reach levels that cause the semiconductor material to overheat and cause thermal damage.

text: This effect is used to advantage in Zener diode regulator circuits. Zener diodes have a low breakdown voltage. A standard value for breakdown voltage is for instance 5.6 V. This means that the voltage at the cathode cannot be more than about 5.6 V higher than the voltage at the anode (although there is a slight rise with current), because the diode will break down – and therefore conduct – if the voltage gets any higher. This in effect limits the voltage over the diode.

text: Another application of reverse biasing is Varicap diodes, where the width of the depletion zone (controlled with the reverse bias voltage) changes the capacitance of the diode.

text: Governing equations[edit]

text: Size of depletion region[edit]

text:
For a p–n junction, letting

C

A

(
x
)

{\displaystyle C_{A}(x)}

 and

C

D

(
x
)

{\displaystyle C_{D}(x)}

 be the concentrations of acceptor and donor atoms respectively, and letting

N

0

(
x
)

{\displaystyle N_{0}(x)}

 and

P

0

(
x
)

{\displaystyle P_{0}(x)}

 be the equilibrium concentrations of electrons and holes respectively, yields, by Poisson's equation:

text:
−

d

2

V

d

x

2

=

ρ
ε

=

q
ε

[

(

N

0

−

P

0

)
+
(

C

D

−

C

A

)

]

{\displaystyle -{\frac {\mathrm {d} ^{2}V}{\mathrm {d} x^{2}}}={\frac {\rho }{\varepsilon }}={\frac {q}{\varepsilon }}\left[(N_{0}-P_{0})+(C_{D}-C_{A})\right]}

text:
where

V

{\displaystyle V}

 is the electric potential,

ρ

{\displaystyle \rho }

 is the charge density,

ε

{\displaystyle \varepsilon }

 is permittivity and

q

{\displaystyle q}

 is the magnitude of the electron charge. Letting

d

p

{\displaystyle d_{p}}

 be the width of the depletion region within the p-side, and letting

d

n

{\displaystyle d_{n}}

 be the width of the depletion region within the n-side, it must be that

text:
d

p

C

A

=

d

n

C

D

{\displaystyle d_{p}C_{A}=d_{n}C_{D}}

text:
because the total charge on either side of the depletion region must cancel out. Therefore, letting

D

{\displaystyle D}

 and

Δ
V

{\displaystyle \Delta V}

 represent the entire depletion region and the potential difference across it,

text:
Δ
V
=

∫

D

∫

q
ε

[

(

N

0

−

P

0

)
+
(

C

D

−

C

A

)

]

d

x

d

x

{\displaystyle \Delta V=\int _{D}\int {\frac {q}{\varepsilon }}\left[(N_{0}-P_{0})+(C_{D}-C_{A})\right]\,\mathrm {d} x\,\mathrm {d} x}

text:
=

C

A

C

D

C

A

+

C

D

q

2
ε

(

d

p

+

d

n

)

2

{\displaystyle ={\frac {C_{A}C_{D}}{C_{A}+C_{D}}}{\frac {q}{2\varepsilon }}(d_{p}+d_{n})^{2}}

text:
where

P

0

=

N

0

=
0

{\displaystyle P_{0}=N_{0}=0}

, because we are in the depletion region. And thus, letting

d

{\displaystyle d}

 be the total width of the depletion region, we get

text:
d
=

2
ε

q

C

A

+

C

D

C

A

C

D

Δ
V

{\displaystyle d={\sqrt {{\frac {2\varepsilon }{q}}{\frac {C_{A}+C_{D}}{C_{A}C_{D}}}\Delta V}}}

text:
Δ
V

{\displaystyle \Delta V}

 can be written as

Δ

V

0

+
Δ

V

ext

{\displaystyle \Delta V_{0}+\Delta V_{\text{ext}}}

, where we have broken up the voltage difference into the equilibrium plus external components. The equilibrium potential results from diffusion forces, and thus we can calculate

Δ

V

0

{\displaystyle \Delta V_{0}}

 by implementing the Einstein relation and assuming the semiconductor is nondegenerate (i.e. the product

P

0

N

0

{\displaystyle {{P}_{0}}{{N}_{0}}}

 is independent of the Fermi energy):

text:
Δ

V

0

=

k
T

q

ln

(

C

A

C

D

P

0

N

0

)

{\displaystyle \Delta {{V}_{0}}={\frac {kT}{q}}\ln \left({\frac {{{C}_{A}}{{C}_{D}}}{{{P}_{0}}{{N}_{0}}}}\right)}

text: where T is the temperature of the semiconductor and k is Boltzmann constant.[2]

text: Current across depletion region[edit]

text: The Shockley ideal diode equation characterizes the current across a p–n junction as a function of external voltage and ambient conditions (temperature, choice of semiconductor, etc.). To see how it can be derived, we must examine the various reasons for current. The convention is that the forward (+) direction be pointed against the diode's built-in potential gradient at equilibrium.

text:
Forward Current (

J

F

{\displaystyle \mathbf {J} _{F}}

)

Diffusion Current: current due to local imbalances in carrier concentration

n

{\displaystyle n}

, via the equation

J

D

∝
−
q
∇
n

{\displaystyle \mathbf {J} _{D}\propto -q\nabla n}

Reverse Current (

J

R

{\displaystyle \mathbf {J} _{R}}

)

Field Current
Generation Current

text: Non-rectifying junctions[edit]

text: This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2013) (Learn how and when to remove this template message)

text: In the above diagrams, contact between the metal wires and the semiconductor material also creates metal–semiconductor junctions called Schottky diodes. In a simplified ideal situation a semiconductor diode would never function, since it would be composed of several diodes connected back-to-front in series. But, in practice, surface impurities within the part of the semiconductor that touches the metal terminals will greatly reduce the width of those depletion layers to such an extent that the metal-semiconductor junctions do not act as diodes. These non-rectifying junctions behave as ohmic contacts regardless of applied voltage polarity.

text: Manufacture[edit]

text: The p-n junction is created by doping, for example by ion implantation, diffusion of dopants, or by epitaxy (growing a layer of crystal doped with one type of dopant on top of a layer of crystal doped with another type of dopant). If two separate pieces of material were used, this would introduce a grain boundary between the semiconductors that would severely inhibit its utility by scattering the electrons and holes.[citation needed]

text: History[edit]

text: The invention of the p–n junction is usually attributed to American physicist Russell Ohl of Bell Laboratories in 1939.[3] Two years later (1941), Vadim Lashkaryov reported discovery of p–n junctions in Cu2O and silver sulphide photocells and selenium rectifiers.[4][5]


document_title: List of National Football League career receiving touchdowns leaders

question_text: who has the most receiving touchdowns in the nfl

text: Players with at least 75 touchdowns[edit]

text:
Key

^

Inducted into the Pro Football Hall of Fame

*

Denotes player who is still active in the NFL

text: Through end of 2017 season.

text:
Rank

Player

Team(s) by season

Touchdowns

1

Jerry Rice^

San Francisco 49ers (1985–2000)Oakland Raiders (2001–2004)Seattle Seahawks (2004)

197

2

Randy Moss^

Minnesota Vikings (1998–2004, 2010)Oakland Raiders (2005–2006)New England Patriots (2007–2010)Tennessee Titans (2010)San Francisco 49ers (2012)

156

3

Terrell Owens^

San Francisco 49ers (1996–2003)Philadelphia Eagles (2004–2005)Dallas Cowboys (2006–2008)Buffalo Bills (2009)Cincinnati Bengals (2010)

153

4

Cris Carter^

Philadelphia Eagles (1987–1989)Minnesota Vikings (1990–2001)Miami Dolphins (2002)

130

5

Marvin Harrison^

Indianapolis Colts (1996–2008)

128

6

Antonio Gates*

San Diego/Los Angeles Chargers (2003–2017)

114

7

Tony Gonzalez

Kansas City Chiefs (1997–2008)Atlanta Falcons (2009–2013)

111

8

Larry Fitzgerald*

Arizona Cardinals (since 2004)

110

9

Tim Brown^

Oakland Raiders (1988–2003)Tampa Bay Buccaneers (2004)

100

Steve Largent^

Seattle Seahawks (1976–1989)

11

Don Hutson^

Green Bay Packers (1935–1945)

99

12

Isaac Bruce

St. Louis Rams (1994–2007)San Francisco 49ers (2008–2009)

91

13

Don Maynard^

New York Giants (1958)New York Jets (1960–1972)

88

14

Andre Reed^

Buffalo Bills (1985–1999)Washington Redskins (2000)

87

15

Lance Alworth^

San Diego Chargers (1962–1970)Dallas Cowboys (1971–1972)

85

Hines Ward

Pittsburgh Steelers (1998–2011)

Paul Warfield^

Cleveland Browns (1964–1969, 1976–1977)Miami Dolphins (1970–1974)

18

Mark Clayton

Miami Dolphins (1983–1992)Green Bay Packers (1993)

84

Irving Fryar

New England Patriots (1984–1992)Miami Dolphins (1993–1995)Philadelphia Eagles (1996–1998)Washington Redskins (1999–2000)

Tommy McDonald^

Philadelphia Eagles (1957–1963)Dallas Cowboys (1964)Los Angeles Rams (1965–1966)Atlanta Falcons (1967)Cleveland Browns (1968)

Andre Rison

Indianapolis Colts (1989)Atlanta Falcons (1990–1994)Cleveland Browns (1995)Jacksonville Jaguars (1996)Green Bay Packers (1996)Kansas City Chiefs (1997–1999)Oakland Raiders (2000)

22

Calvin Johnson

Detroit Lions (2007–2015)

83

23

Anquan Boldin

Arizona Cardinals (2003–2009)Baltimore Ravens (2010–2012)San Francisco 49ers (2013–2015)Detroit Lions (2016)

82

Brandon Marshall*

Denver Broncos (2006–2009)Miami Dolphins 2010–2011)Chicago Bears (2012–2014)New York Jets (2015–2016)New York Giants (2017)

Reggie Wayne

Indianapolis Colts (2001–2014)

25

Art Powell

Philadelphia Eagles (1959)New York Titans (1960–1962)Oakland Raiders (1963–1966)Buffalo Bills (1967)Minnesota Vikings (1968)

81

Steve Smith Sr.

Carolina Panthers (2001–2013)Baltimore Ravens (2014–2016)

28

Harold Carmichael

Philadelphia Eagles (1971–1983)Dallas Cowboys (1984)

79

Charley Taylor^

Washington Redskins (1964–1975, 1977)

30

Joey Galloway

Seattle Seahawks (1995–1999)Dallas Cowboys (2000–2003)Tampa Bay Buccaneers (2004–2008)New England Patriots (2009)Washington Redskins (2010)

77

31

Fred Biletnikoff^

Oakland Raiders (1965–1978)

76

Rob Gronkowski*

New England Patriots (since 2010)

Harold Jackson

Los Angeles Rams (1968, 1973–1977)Philadelphia Eagles (1969–1972)New England Patriots (1978–1981)Minnesota Vikings (1982)Seattle Seahawks (1983)

34

James Lofton^

Green Bay Packers (1978–1986)Los Angeles Raiders (1987–1988)Buffalo Bills (1989–1992)Los Angeles Rams (1993)Philadelphia Eagles (1993)

75

text: Active players with at least 65 touchdowns[edit]

text: Thru end of 2017 season.

text:
Dez Bryant, 73
Jimmy Graham & Jordy Nelson, 69 each.