The Americas comprise the totality of the continents of North and South America. Together, they comprise the New World. Along with their associated islands, they cover 8% of Earth's total surface area and 28.4% of its land area. The topography is dominated by the American Cordillera, a long chain of mountains that runs the length of the west coast; the flatter eastern side of the Americas is dominated by large river basins, such as the Amazon, St. Lawrence River / Great Lakes basin, La Plata. Since the Americas extend 14,000 km from north to south, the climate and ecology vary from the arctic tundra of Northern Canada and Alaska, to the tropical rain forests in Central America and South America. Humans first settled the Americas from Asia between 17,000 years ago. A second migration of Na-Dene speakers followed from Asia; the subsequent migration of the Inuit into the neoarctic around 3500 BCE completed what is regarded as the settlement by the indigenous peoples of the Americas. The first known European settlement in the Americas was by the Norse explorer Leif Erikson.
However, the colonization never became permanent and was abandoned. The Spanish voyages of Christopher Columbus from 1492 to 1502 resulted in permanent contact with European powers, which led to the Columbian exchange and inaugurated a period of exploration and colonization whose effects and consequences persist to the present. Diseases introduced from Europe and West Africa devastated the indigenous peoples, the European powers colonized the Americas. Mass emigration from Europe, including large numbers of indentured servants, importation of African slaves replaced the indigenous peoples. Decolonization of the Americas began with the American Revolution in the 1770s and ended with the Spanish–American War in the late 1890s. All of the population of the Americas resides in independent countries; the Americas are home to over a billion inhabitants, two-thirds of which reside in the United States, Brazil, or Mexico. It is home to eight megacities: New York City, Mexico City, São Paulo, Los Angeles, Buenos Aires, Rio de Janeiro, Bogotá, Lima.
The name America was first recorded in 1507. Christie's auction house says a two-dimensional globe created by Martin Waldseemüller was the earliest recorded use of the term; the name was used in the Cosmographiae Introductio written by Matthias Ringmann, in reference to South America. It was applied to both North and South America by Gerardus Mercator in 1538. America derives from the Latin version of Italian explorer Amerigo Vespucci's first name; the feminine form America accorded with the feminine names of Asia and Europa. In modern English and South America are considered separate continents, taken together are called America or the Americas in the plural; when conceived as a unitary continent, the form is the continent of America in the singular. However, without a clarifying context, singular America in English refers to the United States of America. In the English-speaking world, the term America used to refer to a single continent until the 1950s: According to historians Kären Wigen and Martin W. Lewis, While it might seem surprising to find North and South America still joined into a single continent in a book published in the United States in 1937, such a notion remained common until World War II.
By the 1950s, however all American geographers had come to insist that the visually distinct landmasses of North and South America deserved separate designations. This shift did not seem to happen in Romance-speaking countries, where America is still considered a continent encompassing the North America and South America subcontinents, as well as Central America; the first inhabitants migrated into the Americas from Asia. Habitation sites are known in Alaska and the Yukon from at least 20,000 years ago, with suggested ages of up to 40,000 years. Beyond that, the specifics of the Paleo-Indian migration to and throughout the Americas, including the dates and routes traveled, are subject to ongoing research and discussion. Widespread habitation of the Americas occurred during the late glacial maximum, from 16,000 to 13,000 years ago; the traditional theory has been that these early migrants moved into the Beringia land bridge between eastern Siberia and present-day Alaska around 40,000–17,000 years ago, when sea levels were lowered during the Quaternary glaciation.
These people are believed to have followed herds of now-extinct pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran ice sheets. Another route proposed is that, either on foot or using primitive boats, they migrated down the Pacific coast to South America. Evidence of the latter would since have been covered by a sea level rise of hundreds of meters following the last ice age. Both routes may have
The phonograph is a device for the mechanical recording and reproduction of sound. In its forms, it is called a gramophone or, since the 1940s, a record player; the sound vibration waveforms are recorded as corresponding physical deviations of a spiral groove engraved, incised, or impressed into the surface of a rotating cylinder or disc, called a "record". To recreate the sound, the surface is rotated while a playback stylus traces the groove and is therefore vibrated by it faintly reproducing the recorded sound. In early acoustic phonographs, the stylus vibrated a diaphragm which produced sound waves which were coupled to the open air through a flaring horn, or directly to the listener's ears through stethoscope-type earphones; the phonograph was invented in 1877 by Thomas Edison. While other inventors had produced devices that could record sounds, Edison's phonograph was the first to be able to reproduce the recorded sound, his phonograph recorded sound onto a tinfoil sheet wrapped around a rotating cylinder.
A stylus responding to sound vibrations produced an down or hill-and-dale groove in the foil. Alexander Graham Bell's Volta Laboratory made several improvements in the 1880s and introduced the graphophone, including the use of wax-coated cardboard cylinders and a cutting stylus that moved from side to side in a zigzag groove around the record. In the 1890s, Emile Berliner initiated the transition from phonograph cylinders to flat discs with a spiral groove running from the periphery to near the center, coining the term gramophone for disc record players, predominantly used in many languages. Improvements through the years included modifications to the turntable and its drive system, the stylus or needle, the sound and equalization systems; the disc phonograph record was the dominant audio recording format throughout most of the 20th century. In the 1980s, phonograph use on a standard record player declined due to the rise of the cassette tape, compact disc, other digital recording formats. However, records are still a favorite format for some audiophiles, DJs and turntablists, have undergone a revival in the 2010s.
The original recordings of musicians, which may have been recorded on tape or digital methods, are sometimes re-issued on vinyl. Usage of terminology is not uniform across the English-speaking world. In more modern usage, the playback device is called a "turntable", "record player", or "record changer"; when used in conjunction with a mixer as part of a DJ setup, turntables are colloquially called "decks". In electric phonographs, the motions of the stylus are converted into an analogous electrical signal by a transducer converted back into sound by a loudspeaker; the term phonograph was derived from the Greek words φωνή and γραφή. The similar related terms gramophone and graphophone have similar root meanings; the roots were familiar from existing 19th-century words such as photograph and telephone. The new term may have been influenced by the existing words phonographic and phonography, which referred to a system of phonetic shorthand. Arguably, any device used to record sound or reproduce recorded sound could be called a type of "phonograph", but in common practice the word has come to mean historic technologies of sound recording, involving audio-frequency modulations of a physical trace or groove.
In the late-19th and early-20th centuries, "Phonograph", "Gramophone", "Graphophone", "Zonophone", the like were still brand names specific to various makers of sometimes different machines. "Talking machine" had earlier been used to refer to complicated devices which produced a crude imitation of speech, by simulating the workings of the vocal cords and lips – a potential source of confusion both and now. In British English, "gramophone" may refer to any sound-reproducing machine using disc records, which were introduced and popularized in the UK by the Gramophone Company. "gramophone" was a proprietary trademark of that company and any use of the name by competing makers of disc records was vigorously prosecuted in the courts, but in 1910 an English court decision decreed that it had become a generic term. The term "phonograph" was restricted to machines that used cylinder records. "Gramophone" referred to a wind-up machine. After the introduction of the softer vinyl records, 33 1⁄3-rpm LPs and 45-rpm "single" or two-song records, EPs, the common name became "record player" or "turntable".
The home record player was part of a system that included a radio and might play audiotape cassettes. From about 1960, such a system began to be described as a "hi-fi" or a "stereo". In American English, "phonograph", properly specific to machines made by Edison, was sometimes used in a generic sense as early as the 1890s to include cylinder
The Compact Cassette, Compact Audio Cassette or Musicassette commonly called the cassette tape or tape or cassette, is an analog magnetic tape recording format for audio recording and playback. It was developed by Philips in Hasselt and released in 1962. Compact cassettes come in two forms, either containing content as a prerecorded cassette, or as a recordable "blank" cassette. Both forms are reversible by the user; the compact cassette technology was designed for dictation machines, but improvements in fidelity led the Compact Cassette to supplant the Stereo 8-track cartridge and Reel-to-reel tape recording in most non-professional applications. Its uses ranged from portable audio to home recording to data storage for early microcomputers; the first cassette player designed for use in car dashboards was introduced in 1968. Between the early 1970s and the early 2000s, the cassette was one of the two most common formats for prerecorded music, first alongside the LP record and the compact disc.
Compact Cassettes contain two miniature spools, between which the magnetically coated, polyester-type plastic film is passed and wound. These spools and their attendant parts are held inside a protective plastic shell, 4 by 2.5 by 0.5 inches at its largest dimensions. The tape itself was referred to as "eighth-inch" tape 1⁄8 inches wide, but it was larger: 0.15 inches. Two stereo pairs of tracks or two monaural audio tracks are available on the tape; this reversal is achieved either by flipping the cassette, or by the reversal of tape movement when the mechanism detects that the tape has come to an end. In 1935, decades before the introduction of the Compact Cassette, AEG released the first reel-to-reel tape recorder, with the commercial name "Magnetophon", it was based on the invention of the magnetic tape by Fritz Pfleumer, which used similar technology but with open reels. These instruments were expensive and difficult to use and were therefore used by professionals in radio stations and recording studios.
In 1958, following four years of development, RCA Victor introduced the stereo, quarter-inch, reel-to-reel RCA tape cartridge. However, it was a large cassette, offered few pre-recorded tapes. Despite the multiple versions, it failed. Consumer use of magnetic tape machines took off in the early 1960s, after playback machines reached a comfortable, user-friendly design; this was aided by the introduction of transistors which replaced the bulky and costly vacuum tubes of earlier designs. Reel-to-reel tape became more suitable to household use, but still remained an esoteric product. WIRAG, the Vienna division of Philips developed a cartridge, described as single-hole cassette, adapted from its German described name Einloch-Kassette. Tape and tape speed were identical with the Compact Cassette. Grundig came up with the DC-International derived from blue prints of the Compact Cassette in 1965, but failed on the demand of distributing companies. In 1962, Philips invented the Compact Cassette medium for audio storage, introducing it in Europe on 30 August 1963 at the Berlin Radio Show, in the United States in November 1964, with the trademark name Compact Cassette.
The team at Philips was led by Lou Ottens in Hasselt, Belgium."Philips was competing with Telefunken and Grundig in a race to establish its cassette tape as the worldwide standard, it wanted support from Japanese electronics manufacturers." However, the Philips' Compact Cassette became dominant as a result of Philips' decision to license the format free of charge. Philips released the Norelco Carry-Corder 150 recorder/player in the US in November 1964. By 1966 over 250,000 recorders had been sold in the US alone and Japan soon became the major source of recorders. By 1968, 85 manufacturers had sold over 2.4 million players. By the end of the 1960s, the cassette business was worth an estimated 150 million dollars. In the early years sound quality was mediocre, but it improved by the early 1970s when it caught up with the quality of 8-track tape and kept improving; the Compact Cassette went on to become a popular alternative to the 12-inch vinyl LP during the late 1970s. The mass production of "blank" Compact Cassettes began in 1964 in Germany.
Prerecorded music cassettes were launched in Europe in late 1965. The Mercury Record Company, a US affiliate of Philips, introduced M. C. to the US in July 1966. The initial offering consisted of 49 titles. However, the system had been designed for dictation and portable use, with the audio quality of early players not well suited for music; some early models had an unreliable mechanical design. In 1971, the Advent Corporation introduced their Model 201 tape deck that combined Dolby type B noise reduction and chromium oxide tape, with a commercial-grade tape transport mechanism supplied by the Wollensak camera division of 3M Corporation; this resulted in the format being taken more for musical use, started the era of high fidelity cassettes and players. Although the birth and growth of the cassette began in the 1960s, its cultural moment took place during the 1970s and 1980s; the cassette's popularity grew
A videocassette recorder, VCR, or video recorder is an electromechanical device that records analog audio and analog video from broadcast television or other source on a removable, magnetic tape videocassette, can play back the recording. Use of a VCR to record a television program to play back at a more convenient time is referred to as timeshifting. VCRs can play back prerecorded tapes. In the 1980s and 1990s, prerecorded videotapes were available for purchase and rental, blank tapes were sold to make recordings. Most domestic VCRs are equipped with a television broadcast receiver for TV reception, a programmable clock for unattended recording of a television channel from a start time to an end time specified by the user; these features began as simple mechanical counter-based single-event timers, but were replaced by more flexible multiple-event digital clock timers. In models the multiple timer events could be programmed through a menu interface displayed on the playback TV screen; this feature allowed several programs to be recorded at different times without further user intervention, became a major selling point.
The history of the videocassette recorder follows the history of videotape recording in general. In 1953, Dr. Norikazu Sawazaki developed a prototype helical scan video tape recorder. Ampex introduced the Quadruplex videotape professional broadcast standard format with its Ampex VRX-1000 in 1956, it became the world's first commercially successful videotape recorder using two-inch wide tape. Due to its high price of US$50,000, the Ampex VRX-1000 could be afforded only by the television networks and the largest individual stations. In 1959, Toshiba introduced a "new" method of recording known as helical scan, releasing the first commercial helical scan video tape recorder that year, it was first implemented in reel-to-reel videotape recorders, used with cassette tapes. In 1963 Philips introduced their EL3400 1-inch helical scan recorder, aimed at the business and domestic user, Sony marketed the 2" PV-100, their first reel-to-reel VTR, intended for business, medical and educational use; the Telcan, produced by the UK Nottingham Electronic Valve Company in 1963, was the first home video recorder.
It could be bought as a unit or in kit form for £60, equivalent to £1,100 in 2014 currency. However, there were several drawbacks: it was expensive, was not easy to assemble, could only record 20 minutes at a time, it recorded in the only format available in the UK at the time. The half-inch tape Sony model CV-2000, first marketed in 1965, was their first VTR intended for home use. Ampex and RCA followed in 1965 with their own reel-to-reel monochrome VTRs priced under US$1,000 for the home consumer market; the EIAJ format was a standard half-inch format used by various manufacturers. EIAJ-1 was an open-reel format. EIAJ-2 used a cartridge; the development of the videocassette followed the replacement by cassette of other open reel systems in consumer items: the Stereo-Pak four-track audio cartridge in 1962, the compact audio cassette and Instamatic film cartridge in 1963, the 8-track cartridge in 1965, the Super 8 home movie cartridge in 1966. In 1972, videocassettes of movies became available for home use.
Sony demonstrated a videocassette prototype in October 1969 set it aside to work out an industry standard by March 1970 with seven fellow manufacturers. The result, the Sony U-matic system, introduced in Tokyo in September 1971, was the world's first commercial videocassette format, its cartridges, resembling larger versions of the VHS cassettes, used 3/4-inch tape and had a maximum playing time of 60 minutes extended to 80 minutes. Sony introduced two machines to use the new tapes. U-matic, with its ease of use made other consumer videotape systems obsolete in Japan and North America, where U-matic VCRs were used by television newsrooms schools and businesses, but the high cost - US$1,395 in 1971 for a combination TV/VCR, equivalent to over $8000 in 2014 dollars – kept it out of most homes. In 1970, Philips developed a home video cassette format specially made for a TV station in 1970 and available on the consumer market in 1972. Philips named this format "Video Cassette Recording"; the format was supported by Grundig and Loewe.
It used square cassettes and half-inch tape, mounted on coaxial reels, giving a recording time of one hour. The first model, available in the United Kingdom in 1972, was equipped with a simple timer that used rotary dials. At nearly £600, it was expensive and the format was unsuccessful in the home market; this was followed by a digital timer version in 1975, the N1502. In 1977 a new, long-play version or N1700, which could use the same blank tapes, sold quite well to schools and colleges; the Avco Cartrivision system, a combination television set and VCR from Cartridge Television Inc. that sold for US$1,350, was the first videocassette recorder to have pre-recorded tapes of popular movies available for rent. Like the Philips VCR format, the square Cartrivision cassette had the two reels of half-inch tape mounted on top of each other, but it could record up to 114 minutes, using an early form of video format that recorded every other video field and played it back three times. Cassett
Germany the Federal Republic of Germany, is a country in Central and Western Europe, lying between the Baltic and North Seas to the north, the Alps to the south. It borders Denmark to the north and the Czech Republic to the east and Switzerland to the south, France to the southwest, Luxembourg and the Netherlands to the west. Germany includes 16 constituent states, covers an area of 357,386 square kilometres, has a temperate seasonal climate. With 83 million inhabitants, it is the second most populous state of Europe after Russia, the most populous state lying in Europe, as well as the most populous member state of the European Union. Germany is a decentralized country, its capital and largest metropolis is Berlin, while Frankfurt serves as its financial capital and has the country's busiest airport. Germany's largest urban area is the Ruhr, with its main centres of Essen; the country's other major cities are Hamburg, Cologne, Stuttgart, Düsseldorf, Dresden, Bremen and Nuremberg. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity.
A region named Germania was documented before 100 AD. During the Migration Period, the Germanic tribes expanded southward. Beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation. After the collapse of the Holy Roman Empire, the German Confederation was formed in 1815; the German revolutions of 1848–49 resulted in the Frankfurt Parliament establishing major democratic rights. In 1871, Germany became a nation state when most of the German states unified into the Prussian-dominated German Empire. After World War I and the revolution of 1918–19, the Empire was replaced by the parliamentary Weimar Republic; the Nazi seizure of power in 1933 led to the establishment of a dictatorship, the annexation of Austria, World War II, the Holocaust. After the end of World War II in Europe and a period of Allied occupation, Austria was re-established as an independent country and two new German states were founded: West Germany, formed from the American and French occupation zones, East Germany, formed from the Soviet occupation zone.
Following the Revolutions of 1989 that ended communist rule in Central and Eastern Europe, the country was reunified on 3 October 1990. Today, the sovereign state of Germany is a federal parliamentary republic led by a chancellor, it is a great power with a strong economy. As a global leader in several industrial and technological sectors, it is both the world's third-largest exporter and importer of goods; as a developed country with a high standard of living, it upholds a social security and universal health care system, environmental protection, a tuition-free university education. The Federal Republic of Germany was a founding member of the European Economic Community in 1957 and the European Union in 1993, it is part of the Schengen Area and became a co-founder of the Eurozone in 1999. Germany is a member of the United Nations, NATO, the G7, the G20, the OECD. Known for its rich cultural history, Germany has been continuously the home of influential and successful artists, musicians, film people, entrepreneurs, scientists and inventors.
Germany has a large number of World Heritage sites and is among the top tourism destinations in the world. The English word Germany derives from the Latin Germania, which came into use after Julius Caesar adopted it for the peoples east of the Rhine; the German term Deutschland diutisciu land is derived from deutsch, descended from Old High German diutisc "popular" used to distinguish the language of the common people from Latin and its Romance descendants. This in turn descends from Proto-Germanic *þiudiskaz "popular", derived from *þeudō, descended from Proto-Indo-European *tewtéh₂- "people", from which the word Teutons originates; the discovery of the Mauer 1 mandible shows that ancient humans were present in Germany at least 600,000 years ago. The oldest complete hunting weapons found anywhere in the world were discovered in a coal mine in Schöningen between 1994 and 1998 where eight 380,000-year-old wooden javelins of 1.82 to 2.25 m length were unearthed. The Neander Valley was the location where the first non-modern human fossil was discovered.
The Neanderthal 1 fossils are known to be 40,000 years old. Evidence of modern humans dated, has been found in caves in the Swabian Jura near Ulm; the finds included 42,000-year-old bird bone and mammoth ivory flutes which are the oldest musical instruments found, the 40,000-year-old Ice Age Lion Man, the oldest uncontested figurative art discovered, the 35,000-year-old Venus of Hohle Fels, the oldest uncontested human figurative art discovered. The Nebra sky disk is a bronze artefact created during the European Bronze Age attributed to a site near Nebra, Saxony-Anhalt, it is part of UNESCO's Memory of the World Programme. The Germanic tribes are thought to date from the Pre-Roman Iron Age. From southern Scandinavia and north Germany, they expanded south and west from the 1st century BC, coming into contact with the Celtic tribes of Gaul as well
Electronics comprises the physics, engineering and applications that deal with the emission and control of electrons in vacuum and matter. The identification of the electron in 1897, along with the invention of the vacuum tube, which could amplify and rectify small electrical signals, inaugurated the field of electronics and the electron age. Electronics deals with electrical circuits that involve active electrical components such as vacuum tubes, diodes, integrated circuits and sensors, associated passive electrical components, interconnection technologies. Electronic devices contain circuitry consisting or of active semiconductors supplemented with passive elements; the nonlinear behaviour of active components and their ability to control electron flows makes amplification of weak signals possible. Electronics is used in information processing, telecommunication, signal processing; the ability of electronic devices to act as switches makes digital information-processing possible. Interconnection technologies such as circuit boards, electronics packaging technology, other varied forms of communication infrastructure complete circuit functionality and transform the mixed electronic components into a regular working system, called an electronic system.
An electronic system may be a component of a standalone device. Electrical and electromechanical science and technology deals with the generation, switching and conversion of electrical energy to and from other energy forms; this distinction started around 1906 with the invention by Lee De Forest of the triode, which made electrical amplification of weak radio signals and audio signals possible with a non-mechanical device. Until 1950 this field was called "radio technology" because its principal application was the design and theory of radio transmitters and vacuum tubes; as of 2018 most electronic devices use semiconductor components to perform electron control. The study of semiconductor devices and related technology is considered a branch of solid-state physics, whereas the design and construction of electronic circuits to solve practical problems come under electronics engineering; this article focuses on engineering aspects of electronics. Digital electronics Analogue electronics Microelectronics Circuit design Integrated circuits Power electronics Optoelectronics Semiconductor devices Embedded systems An electronic component is any physical entity in an electronic system used to affect the electrons or their associated fields in a manner consistent with the intended function of the electronic system.
Components are intended to be connected together by being soldered to a printed circuit board, to create an electronic circuit with a particular function. Components may be packaged singly, or in more complex groups as integrated circuits; some common electronic components are capacitors, resistors, transistors, etc. Components are categorized as active or passive. Vacuum tubes were among the earliest electronic components, they were solely responsible for the electronics revolution of the first half of the twentieth century. They allowed for vastly more complicated systems and gave us radio, phonographs, long-distance telephony and much more, they played a leading role in the field of microwave and high power transmission as well as television receivers until the middle of the 1980s. Since that time, solid-state devices have all but taken over. Vacuum tubes are still used in some specialist applications such as high power RF amplifiers, cathode ray tubes, specialist audio equipment, guitar amplifiers and some microwave devices.
In April 1955, the IBM 608 was the first IBM product to use transistor circuits without any vacuum tubes and is believed to be the first all-transistorized calculator to be manufactured for the commercial market. The 608 contained more than 3,000 germanium transistors. Thomas J. Watson Jr. ordered all future IBM products to use transistors in their design. From that time on transistors were exclusively used for computer logic and peripherals. Circuits and components can be divided into two groups: digital. A particular device may consist of circuitry that has a mix of the two types. Most analog electronic appliances, such as radio receivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a continuous range of voltage or current as opposed to discrete levels as in digital circuits; the number of different analog circuits so far devised is huge because a'circuit' can be defined as anything from a single component, to systems containing thousands of components.
Analog circuits are sometimes called linear circuits although many non-linear effects are used in analog circuits such as mixers, etc. Good examples of analog circuits include vacuum tube and transistor amplifiers, operational amplifiers and oscillators. One finds modern circuits that are analog; these days analog circuitry may use digital or microprocessor techniques to improve performance. This type of circuit is called "mixed signal" rather than analog or digital. Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non-linear