Automated teller machine
An automated teller machine is an electronic telecommunications device that enables customers of financial institutions to perform financial transactions, such as cash withdrawals, transfer funds, or obtaining account information, at any time and without the need for direct interaction with bank staff. ATMs are known by a variety of names, including automatic teller machine in the United States redundantly ATM machine, automated banking machine. Although ABM is used in Canada, ATM is still commonly used in Canada and many Canadian organizations use ATM over ABM. In British English, the terms cash point, cash machine, "hole in the wall" are most used. Other terms include any time money, nibank, tyme machine, cash dispenser, bankomat or bancomat. Many ATMs have a sign above them, indicating the name of the bank or organisation that owns the ATM, including the networks to which it can connect. In Canada, ABMs that are not operated by a financial institution are known as "white-label ABMs". According to the ATM Industry Association, there are now close to 3.5 million ATMs installed worldwide.
However, the use of ATMs in Australia is declining – most notably in retail precincts. On most modern ATMs, customers are identified by inserting a plastic ATM card into the ATM, with authentication being by the customer entering a personal identification number, which must match the PIN stored in the chip on the card, or in the issuing financial institution's database. Using an ATM, customers can access their bank deposit or credit accounts in order to make a variety of financial transactions such as cash withdrawals, check balances, or credit mobile phones. ATMs can be used to withdraw cash in a foreign country. If the currency being withdrawn from the ATM is different from that in which the bank account is denominated, the money will be converted at the financial institution's exchange rate; the idea of out-of-hours cash distribution developed from bankers' needs in Japan, the United Kingdom, the United States. Little is known of the Japanese device other than that it was called "Computer Loan Machine" and supplied cash as a three-month loan at 5% p.a. after inserting a credit card.
The device was operational in 1966. Adrian Ashfield invented the basic idea of a card combining the key and user's identity in February 1962; this was granted UK Patent 959,713 for "Access Controller" in June 1964 and assigned to W. S. Atkins & Partners who employed Ashfield, he was paid ten shillings for the standard sum for all patents. It was intended to dispense petrol but the patent covered all uses. In the US patent record, Luther George Simjian has been credited with developing a "prior art device", his 132nd patent, first filed on 30 June 1960. The roll-out of this machine, called Bankograph, was delayed by a couple of years, due in part to Simjian's Reflectone Electronics Inc. being acquired by Universal Match Corporation. An experimental Bankograph was installed in New York City in 1961 by the City Bank of New York, but removed after six months due to the lack of customer acceptance; the Bankograph did not have cash dispensing features. It is accepted that the first cash machine was put into use by Barclays Bank in its Enfield Town branch in North London, United Kingdom, on 27 June 1967.
This machine was inaugurated by English comedy actor Reg Varney. This instance of the invention is credited to the engineering team led by John Shepherd-Barron of printing firm De La Rue, awarded an OBE in the 2005 New Year Honours. Transactions were initiated by inserting paper cheques issued by a teller or cashier, marked with carbon-14 for machine readability and security, which in a model were matched with a six-digit personal identification number. Shepherd-Barron stated "It struck me there must be a way I could get my own money, anywhere in the world or the UK. I hit upon the idea of a chocolate bar dispenser, but replacing chocolate with cash."The Barclays–De La Rue machine beat the Swedish saving banks' and a company called Metior's machine by a mere nine days and Westminster Bank's–Smith Industries–Chubb system by a month. The online version of the Swedish machine is listed to have been operational on 6 May 1968, while claiming to be the first online ATM in the world; the collaboration of a small start-up called Speytec and Midland Bank developed a fourth machine, marketed after 1969 in Europe and the US by the Burroughs Corporation.
The patent for this device was filed in September 1969 by John David Edwards, Leonard Perkins, John Henry Donald, Peter Lee Chappell, Sean Benjamin Newcombe, Malcom David Roe. Both the DACS and MD2 accepted only a single-use token or voucher, retained by the machine, while the Speytec worked with a card with a magnetic stripe at the back, they used principles including Carbon-14 and low-coercivity magnetism in order to make fraud more difficult. The idea of a PIN stored on the card was developed by a group of engineers working at Smiths Group on the Chubb MD2 in 1965 and, credited to James Goodfellow; the essence of this system was that it enable
A prison known as a correctional facility, gaol, detention center, remand center, or internment facility, is a facility in which inmates are forcibly confined and denied a variety of freedoms under the authority of the state. Prisons are most used within a criminal justice system: people charged with crimes may be imprisoned until their trial. In simplest terms, a prison can be described as a building in which people are held as a punishment for a crime they have committed. Prisons can be used as a tool of political repression by authoritarian regimes, their perceived opponents may be imprisoned for political crimes without trial or other legal due process. In times of war, prisoners of war or detainees may be detained in military prisons or prisoner of war camps, large groups of civilians might be imprisoned in internment camps. In American English and jail are treated as having separate definitions; the term prison or penitentiary tends to describe institutions that incarcerate people for longer periods of time, such as many years, are operated by the state or federal governments.
The term jail tends to describe institutions for confining people for shorter periods of time and are operated by local governments. Outside of North America and jail have the same meaning. Common slang terms for a prison include: "the pokey", "the slammer", "the can", "the clink", "the joint", "the calaboose", "the hoosegow" and "the big house". Slang terms for imprisonment include: "behind bars", "in stir" and "up the river"; the use of prisons can be traced back to the rise of the state as a form of social organization. Corresponding with the advent of the state was the development of written language, which enabled the creation of formalized legal codes as official guidelines for society; the best known of these early legal codes is the Code of Hammurabi, written in Babylon around 1750 BC. The penalties for violations of the laws in Hammurabi's Code were exclusively centered on the concept of lex talionis, whereby people were punished as a form of vengeance by the victims themselves; this notion of punishment as vengeance or retaliation can be found in many other legal codes from early civilizations, including the ancient Sumerian codes, the Indian Manusmriti, the Hermes Trismegistus of Egypt, the Israelite Mosaic Law.
Some Ancient Greek philosophers, such as Plato, began to develop ideas of using punishment to reform offenders instead of using it as retribution. Imprisonment as a penalty was used for those who could not afford to pay their fines. Since impoverished Athenians could not pay their fines, leading to indefinite periods of imprisonment, time limits were set instead; the prison in Ancient Athens was known as the desmoterion. The Romans were among the first to use prisons as a form of punishment, rather than for detention. A variety of existing structures were used to house prisoners, such as metal cages, basements of public buildings, quarries. One of the most notable Roman prisons was the Mamertine Prison, established around 640 B. C. by Ancus Marcius. The Mamertine Prison was located within a sewer system beneath ancient Rome and contained a large network of dungeons where prisoners were held in squalid conditions, contaminated with human waste. Forced labor on public works projects was a common form of punishment.
In many cases, citizens were sentenced to slavery in ergastula. During the Middle Ages in Europe, castles and the basements of public buildings were used as makeshift prisons; the possession of the right and the capability to imprison citizens, granted an air of legitimacy to officials at all levels of government, from kings to regional courts to city councils. Another common punishment was sentencing people to galley slavery, which involved chaining prisoners together in the bottoms of ships and forcing them to row on naval or merchant vessels. From the late 17th century and during the 18th century, popular resistance to public execution and torture became more widespread both in Europe and in the United States. Under the Bloody Code, with few sentencing alternatives, imposition of the death penalty for petty crimes, such as theft, was proving unpopular with the public. Rulers began looking for means to punish and control their subjects in a way that did not cause people to associate them with spectacles of tyrannical and sadistic violence.
They developed systems of mass incarceration with hard labor, as a solution. The prison reform movement that arose at this time was influenced by two somewhat contradictory philosophies; the first was based in Enlightenment ideas of utilitarianism and rationalism, suggested that prisons should be used as a more effective substitute for public corporal punishments such as whipping, etc. This theory, referred to as deterrence, claims tha
Thomson Reuters Corporation is a Canadian multinational mass media and information firm. The firm was founded in Toronto, Canada, where it is headquartered at 333 Bay Street in Downtown Toronto. Thomson Reuters shares are cross listed on the Toronto Stock Exchange and the New York Stock Exchange. Thomson Reuters was created by the Thomson Corporation's purchase of the British company Reuters Group in April 2008, is majority owned by The Woodbridge Company, a holding company for the Thomson family. Thomson Reuters was ranked as Canada's "leading corporate brand" in the 2010 Interbrand Best Canadian Brands ranking. Thomson Reuters operates in more than 100 countries, has more than 45,000 employees; the company was founded by Roy Thomson in 1934 in Ontario as the publisher of The Timmins Daily Press. In 1953, Thomson moved to Scotland the following year, he consolidated his media position in Scotland in 1957 when he won the franchise for Scottish Television. In 1959, he bought the Kemsley Group, a purchase that gave him control of the Sunday Times.
He separately acquired the Times in 1967. He moved into the airline business in 1965, when he acquired Britannia Airways and into oil and gas exploration in 1971 when he participated in a consortium to exploit reserves in the North Sea. In the 1970s, following the death of Thomson, the company withdrew from national newspapers and broadcast media, selling the Times, the Sunday Times and Scottish Television and instead moved into publishing, buying Sweet & Maxwell in 1988; the company at this time was known as the International Thomson Organisation Ltd. In 1989, ITOL merged with Thomson Newspapers. In 1996, The Thomson Corporation acquired West Publishing, a purveyor of legal research and solutions including Westlaw; the Company was founded by Paul Julius Reuter in 1851 in London as a business transmitting stock market quotations. Reuter set up his "Submarine Telegraph" office in October 1851 and negotiated a contract with the London Stock Exchange to provide stock prices from the continental exchanges in return for access to London prices, which he supplied to stockbrokers in Paris, France.
In 1865, Reuters in London was the first organization to report the assassination of Abraham Lincoln. The company was involved in developing the use of radio in 1923, it was acquired by the British National & Provincial Press in 1941 and first listed on the London Stock Exchange in 1984. Reuters began to grow in the 1980s, widening the range of its business products and expanding its global reporting network for media and economic services: key product launches included Equities 2000, Dealing 2000-2, Business Briefing, Reuters Television for the financial markets, 3000 Series and the Reuters 3000 Xtra service; the Thomson Corporation acquired Reuters Group PLC to form Thomson Reuters on April 17, 2008. Thomson Reuters operated under a dual-listed company structure and had two parent companies, both of which were publicly listed — Thomson Reuters Corporation and Thomson Reuters PLC. In 2009, it unified its dual listed company structure and stopped its listing on the London Stock Exchange and NASDAQ.
It is now listed only as Thomson Reuters Corporation on the New York Stock Exchange and Toronto Stock Exchange. On February 13, 2013, Thomson Reuters announced it would cut 2,500 jobs to cut cost in its Legal and Risk division. On October 29, 2013, Thomson Reuters announced it would cut another 3,000 jobs in those same three divisions; the Thomson-Reuters merger transaction was reviewed by the U. S. Department of Justice and by the European Commission. On February 19, 2008, both the Department of Justice and the Commission cleared the transaction subject to minor divestments; the Department of Justice required the parties to sell copies of the data contained in the following products: Thomson's WorldScope, a global fundamentals product. The proposed settlement further requires the licensing of related intellectual property, access to personnel, transitional support to ensure that the buyer of each set of data can continue to update its database so as to continue to offer users a viable and competitive product.
The European Commission imposed similar divestments: according to the Commission's press release, "the parties committed to divest the databases containing the content sets of such financial information products, together with relevant assets and customer base as appropriate to allow purchasers of the databases and assets to establish themselves as a credible competitive force in the marketplace in competition with the merged entity, re-establishing the pre-merger rivalry in the respective fields."These remedies were viewed as minor given the scope of the transaction. According to the Financial Times, "the remedy proposed by the competition authorities will affect no more than $25m of the new Thomson Reuters group’s $13bn-plus combined revenues."The transaction was cleared by the Canadian Competition Bureau. In November 2009, The European Commission opened formal anti-trust proceedings against Thomson Reuters concerning a potential infringement of the EC Treaty's rules on abuse of a dominant market position.
The Commission investigated Thomson Reuters' practices in the area of real-time market datafeeds, in particular whether customers or competitors were prevented from translating Reuters Instrument Codes to alternative identification codes of other datafeed suppliers to the detriment of competition. In Dec
The yen is the official currency of Japan. It is the third most traded currency in the foreign exchange market after the United States dollar and the euro, it is widely used as a reserve currency after the U. S. dollar, the euro, the pound sterling. The concept of the yen was a component of the Meiji government's modernization program of Japan's economy. Before the Meiji Restoration, Japan's feudal fiefs all issued their own money, hansatsu, in an array of incompatible denominations; the New Currency Act of 1871 did away with these and established the yen, defined as 1.5 g of gold, or 24.26 g of silver, as the new decimal currency. The former han became prefectures and their mints private chartered banks, which retained the right to print money. To bring an end to this situation the Bank of Japan was founded in 1882 and given a monopoly on controlling the money supply. Following World War II the yen lost much of its prewar value. To stabilize the Japanese economy the exchange rate of the yen was fixed at ¥360 per $1 as part of the Bretton Woods system.
When that system was abandoned in 1971, the yen was allowed to float. The yen had appreciated to a peak of ¥271 per $1 in 1973 underwent periods of depreciation and appreciation due to the 1973 oil crisis, arriving at a value of ¥227 per $1 by 1980. Since 1973, the Japanese government has maintained a policy of currency intervention, the yen is therefore under a "dirty float" regime; this intervention continues to this day. The Japanese government focuses on a competitive export market, tries to ensure a low yen value through a trade surplus; the Plaza Accord of 1985 temporarily changed this situation from its average of ¥239 per US$1 in 1985 to ¥128 in 1988 and led to a peak value of ¥80 against the U. S. dollar in 1995 increasing the value of Japan’s GDP to that of the United States. Since that time, the yen has decreased in value; the Bank of Japan maintains a policy of zero to near-zero interest rates and the Japanese government has had a strict anti-inflation policy. Yen derives from the Japanese word 圓, which borrows its phonetic reading from Chinese yuan, similar to North Korean won and South Korean won.
The Chinese had traded silver in mass called sycees and when Spanish and Mexican silver coins arrived, the Chinese called them "silver rounds" for their circular shapes. The coins and the name appeared in Japan. While the Chinese replaced 圓 with 元, the Japanese continued to use the same word, given the shinjitai form 円 in reforms at the end of World War II; the spelling and pronunciation "yen" is standard in English. This is because when Japan was first encountered by Europeans around the 16th century, Japanese /e/ and /we/ both had been pronounced and Portuguese missionaries had spelled them "ye"; some time thereafter, by the middle of the 18th century, /e/ and /we/ came to be pronounced as in modern Japanese, although some regions retain the pronunciation. Walter Henry Medhurst, who had neither been to Japan nor met any Japanese, having consulted a Japanese-Dutch dictionary, spelled some "e"s as "ye" in his An English and Japanese, Japanese and English Vocabulary. In the early Meiji era, James Curtis Hepburn, following Medhurst, spelled all "e"s as "ye" in his A Japanese and English dictionary.
That was the first full-scale Japanese-English/English-Japanese dictionary, which had a strong influence on Westerners in Japan and prompted the spelling "yen". Hepburn revised most "ye"s to "e" in the 3rd edition in order to mirror the contemporary pronunciation, except "yen"; this was already fixed and has remained so since. In the 19th century, silver Spanish dollar coins were common throughout Southeast Asia, the China coast, Japan; these coins had been introduced through Manila over a period of two hundred and fifty years, arriving on ships from Acapulco in Mexico. These ships were known as the Manila galleons; until the 19th century, these silver dollar coins were actual Spanish dollars minted in the new world at Mexico City. But from the 1840s, they were replaced by silver dollars of the new Latin American republics. In the half of the 19th century, some local coins in the region were made in the resemblance of the Mexican peso; the first of these local silver coins was the Hong Kong silver dollar coin, minted in Hong Kong between the years 1866 and 1869.
The Chinese were slow to accept unfamiliar coinage and preferred the familiar Mexican dollars, so the Hong Kong government ceased minting these coins and sold the mint machinery to Japan. The Japanese decided to adopt a silver dollar coinage under the name of'yen', meaning'a round object'; the yen was adopted by the Meiji government in an Act signed on June 27, 1871. The new currency was introduced beginning from July of that year; the yen was therefore a dollar unit, like all dollars, descended from the Spanish Pieces of eight, up until the year 1873, all the dollars in the world had more or less the same value. The yen replaced a complex monetary system of the Edo period based on the mon.. The New Currency Act of 1871, stipulated the adoption of the decimal accounting system of yen and rin, with the coins being round and manufactured using Western machinery; the yen
In electrical engineering, a switch is an electrical component that can "make" or "break" an electrical circuit, interrupting the current or diverting it from one conductor to another. The mechanism of a switch restores the conducting path in a circuit when it is operated, it may be operated manually, for example, a light switch or a keyboard button, may be operated by a moving object such as a door, or may be operated by some sensing element for pressure, temperature or flow. A switch will have one or more sets of contacts, which may operate sequentially, or alternately. Switches in high-powered circuits must operate to prevent destructive arcing, may include special features to assist in interrupting a heavy current. Multiple forms of actuators are used for operation by hand or to sense position, temperature or flow. Special types are used, for example, for control of machinery, to reverse electric motors, or to sense liquid level. Many specialized forms exist. A common use is control of lighting, where multiple switches may be wired into one circuit to allow convenient control of light fixtures.
By analogy with the devices that select one or more possible paths for electric currents, devices that route information in a computer network are called "switches" - these are more complicated than simple electromechanical toggles or pushbutton devices, operate without direct human interaction. The most familiar form of switch is a manually operated electromechanical device with one or more sets of electrical contacts, which are connected to external circuits; each set of contacts can be in one of two states: either "closed" meaning the contacts are touching and electricity can flow between them, or "open", meaning the contacts are separated and the switch is nonconducting. The mechanism actuating the transition between these two states are either an "alternate action" or "momentary" type. A switch may be directly manipulated by a human as a control signal to a system, such as a computer keyboard button, or to control power flow in a circuit, such as a light switch. Automatically operated switches can be used to control the motions of machines, for example, to indicate that a garage door has reached its full open position or that a machine tool is in a position to accept another workpiece.
Switches may be operated by process variables such as pressure, flow, current and force, acting as sensors in a process and used to automatically control a system. For example, a thermostat is a temperature-operated switch used to control a heating process. A switch, operated by another electrical circuit is called a relay. Large switches may be remotely operated by a motor drive mechanism; some switches are used to isolate electric power from a system, providing a visible point of isolation that can be padlocked if necessary to prevent accidental operation of a machine during maintenance, or to prevent electric shock. An ideal switch would have no voltage drop when closed, would have no limits on voltage or current rating, it would have zero rise time and fall time during state changes, would change state without "bouncing" between on and off positions. Practical switches fall short of this ideal; the ideal switch is used in circuit analysis as it simplifies the system of equations to be solved, but this can lead to a less accurate solution.
Theoretical treatment of the effects of non-ideal properties is required in the design of large networks of switches, as for example used in telephone exchanges. In the simplest case, a switch has two conductive pieces metal, called contacts, connected to an external circuit, that touch to complete the circuit, separate to open the circuit; the contact material is chosen for its resistance to corrosion, because most metals form insulating oxides that would prevent the switch from working. Contact materials are chosen on the basis of electrical conductivity, mechanical strength, low cost and low toxicity. Sometimes the contacts are plated with noble metals, for their excellent conductivity and resistance to corrosion, they may be designed to wipe against each other to clean off any contamination. Nonmetallic conductors, such as conductive plastic, are sometimes used. To prevent the formation of insulating oxides, a minimum wetting current may be specified for a given switch design. In electronics, switches are classified according to the arrangement of their contacts.
A pair of contacts is said to be "closed". When the contacts are separated by an insulating air gap, they are said to be "open", no current can flow between them at normal voltages; the terms "make" for closure of contacts and "break" for opening of contacts are widely used. The terms pole and throw are used to describe switch contact variations; the number of "poles" is the number of electrically separate switches which are controlled by a single physical actuator. For example, a "2-pole" switch has two separate, parallel sets of contacts that open and close in unison via the same mechanism; the number of "throws" is the number of separate wiring path choices other than "open" that the switch can adopt for each pole. A single-throw switch has one pair of contacts that can either be open. A double-throw switch has a contact that can be connected to either of two other contacts, a triple-throw has a contact which can be connected to one of three other contacts, etc. In a switch where the contacts remain i
Kyoto Kyoto City, is the capital city of Kyoto Prefecture, located in the Kansai region of Japan. It is best known in Japanese history for being the former Imperial capital of Japan for more than one thousand years, as well as a major part of the Kyoto-Osaka-Kobe metropolitan area. In Japanese, Kyoto was called Kyō, Miyako, or Kyō no Miyako. In the 11th century, the city was renamed Kyoto, from the Chinese calligraphic, jingdu. After the city of Edo was renamed Tokyo in 1868, the seat of the Emperor was moved there, Kyoto was for a short time known as Saikyō. Kyoto is sometimes called the thousand-year capital; the National Diet never passed any law designating a capital. Foreign spellings for the city's name have included Kioto and Meaco, utilised by Dutch cartographers. Another term used to refer to the city in the pre-modern period was Keishi, meaning "urba" or "capital". Ample archaeological evidence suggests human settlement in Kyoto began as early as the Paleolithic period, although not much published material is retained about human activity in the area before the 6th century, around which time the Shimogamo Shrine is believed to have been established.
During the 8th century, when powerful Buddhist clergy became involved in the affairs of the Imperial government, Emperor Kanmu chose to relocate the capital in order to distance it from the clerical establishment in Nara. His last choice for the site was the village of Uda, in the Kadono district of Yamashiro Province; the new city, Heian-kyō, a scaled replica of the Tang capital Chang'an, became the seat of Japan's imperial court in 794, beginning the Heian period of Japanese history. Although military rulers established their governments either in Kyoto or in other cities such as Kamakura and Edo, Kyoto remained Japan's capital until the transfer of the imperial court to Tokyo in 1869 at the time of the Imperial Restoration; the city suffered extensive destruction in the Ōnin War of 1467–1477, did not recover until the mid-16th century. During the Ōnin War, the shugo collapsed, power was divided among the military families. Battles between samurai factions spilled into the streets, came to involve the court nobility and religious factions as well.
Nobles' mansions were transformed into fortresses, deep trenches dug throughout the city for defense and as firebreaks, numerous buildings burned. The city has not seen such widespread destruction since. In the late 16th century, Toyotomi Hideyoshi reconstructed the city by building new streets to double the number of north-south streets in central Kyoto, creating rectangle blocks superseding ancient square blocks. Hideyoshi built earthwork walls called odoi encircling the city. Teramachi Street in central Kyoto is a Buddhist temple quarter where Hideyoshi gathered temples in the city. Throughout the Edo period, the economy of the city flourished as one of three major cities in Japan, the others being Osaka and Edo; the Hamaguri rebellion of 1864 burnt down 28,000 houses in the city which showed the rebels' dissatisfaction towards the Tokugawa Shogunate. The subsequent move of the Emperor to Tokyo in 1869 weakened the economy; the modern city of Kyoto was formed on April 1, 1889. The construction of Lake Biwa Canal in 1890 was one measure taken to revive the city.
The population of the city exceeded one million in 1932. There was some consideration by the United States of targeting Kyoto with an atomic bomb at the end of World War II because, as an intellectual center of Japan, it had a population large enough to persuade the emperor to surrender. In the end, at the insistence of Henry L. Stimson, Secretary of War in the Roosevelt and Truman administrations, the city was removed from the list of targets and replaced by Nagasaki; the city was spared from conventional bombing as well, although small-scale air raids did result in casualties. As a result, the Imperial City of Kyoto is one of the few Japanese cities that still have an abundance of prewar buildings, such as the traditional townhouses known as machiya. However, modernization is continually breaking down the traditional Kyoto in favor of newer architecture, such as the Kyōto Station complex. Kyoto became a city designated by government ordinance on September 1, 1956. In 1997, Kyoto hosted the conference.
Kyoto is located in a valley, part of the Yamashiro Basin, in the eastern part of the mountainous region known as the Tamba highlands. The Yamashiro Basin is surrounded on three sides by mountains known as Higashiyama and Nishiyama, with a height just above 1,000 metres above sea level; this interior positioning results in cold winters. There are three rivers in the basin, the Ujigawa to the south, the Katsuragawa to the west, the Kamogawa to the east. Kyoto City takes up 17.9% of the land in the prefecture with an area of 827.9 square kilometres. The original city was arranged in accordance with traditional Chinese feng shui following the model of the ancient Chinese capital of Chang'an; the Imperial Palace faced south. The streets in the modern-day wards of Nakagyō, Shimogyō, Kamigyō-ku still follow a grid pattern. Today, the main business district is located to the south of the old Imperial Palace, with the less-populated northern area retaining a fa
In the broadest definition, a sensor is a device, module, or subsystem whose purpose is to detect events or changes in its environment and send the information to other electronics a computer processor. A sensor is always used with other electronics. Sensors are used in everyday objects such as touch-sensitive elevator buttons and lamps which dim or brighten by touching the base, besides innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms, the uses of sensors have expanded beyond the traditional fields of temperature, pressure or flow measurement, for example into MARG sensors. Moreover, analog sensors such as potentiometers and force-sensing resistors are still used. Applications include manufacturing and machinery and aerospace, medicine and many other aspects of our day-to-day life. A sensor's sensitivity indicates how much the sensor's output changes when the input quantity being measured changes. For instance, if the mercury in a thermometer moves 1 cm when the temperature changes by 1 °C, the sensitivity is 1 cm/°C.
Some sensors can affect what they measure. Sensors are designed to have a small effect on what is measured. Technological progress allows more and more sensors to be manufactured on a microscopic scale as microsensors using MEMS technology. In most cases, a microsensor reaches a higher speed and sensitivity compared with macroscopic approaches. A good sensor obeys the following rules:: it is sensitive to the measured property it is insensitive to any other property to be encountered in its application, it does not influence the measured property. Most sensors have a linear transfer function; the sensitivity is defined as the ratio between the output signal and measured property. For example, if a sensor measures temperature and has a voltage output, the sensitivity is a constant with the units; the sensitivity is the slope of the transfer function. Converting the sensor's electrical output to the measured units requires dividing the electrical output by the slope. In addition, an offset is added or subtracted.
For example, -40 must be added to the output. For an analog sensor signal to be processed, or used in digital equipment, it needs to be converted to a digital signal, using an analog-to-digital converter. Since sensors cannot replicate an ideal transfer function, several types of deviations can occur which limit sensor accuracy: Since the range of the output signal is always limited, the output signal will reach a minimum or maximum when the measured property exceeds the limits; the full scale range defines the minimum values of the measured property. The sensitivity may in practice differ from the value specified; this is called a sensitivity error. This is an error in the slope of a linear transfer function. If the output signal differs from the correct value by a constant, the sensor has an offset error or bias; this is an error in the y-intercept of a linear transfer function. Nonlinearity is deviation of a sensor's transfer function from a straight line transfer function; this is defined by the amount the output differs from ideal behavior over the full range of the sensor noted as a percentage of the full range.
Deviation caused by rapid changes of the measured property over time is a dynamic error. This behavior is described with a bode plot showing sensitivity error and phase shift as a function of the frequency of a periodic input signal. If the output signal changes independent of the measured property, this is defined as drift. Long term drift over months or years is caused by physical changes in the sensor. Noise is a random deviation of the signal. A hysteresis error causes the output value to vary depending on the previous input values. If a sensor's output is different depending on whether a specific input value was reached by increasing vs. decreasing the input the sensor has a hysteresis error. If the sensor has a digital output, the output is an approximation of the measured property; this error is called quantization error. If the signal is monitored digitally, the sampling frequency can cause a dynamic error, or if the input variable or added noise changes periodically at a frequency near a multiple of the sampling rate, aliasing errors may occur.
The sensor may to some extent be sensitive to properties other than the property being measured. For example, most sensors are influenced by the temperature of their environment. A hysteresis error causes the output value to vary depending on the previous input values. If a sensor's output is different depending on whether a specific input value was reached by increasing vs. decreasing the input the sensor has a hysteresis error. All these deviations can be classified as random errors. Systematic errors can sometimes be compensated for by means of some kind of calibration strategy. Noise is a random error that can be reduced by signal processing, such as filtering at the expense of the dynamic behavior of the sensor; the resolution of a sensor is the smallest change it can detect in the quantity that it is measuring. The resolution of a sensor with a digital output is the resolution of the digital output; the resolution is related to the precision with which the mea