An electrical connector, is an electro-mechanical device used to join electrical terminations and create an electrical circuit. Electrical connectors consist of plugs and jacks, the connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or devices. An adapter can be used to bring together dissimilar connectors. There are hundreds of types of electrical connectors, connectors may join two lengths of flexible copper wire or cable, or connect a wire or cable to an electrical terminal. In computing, a connector can be known as a physical interface. Cable glands, known as cable connectors in the US, connect wires to devices rather than electrically and are distinct from quick-disconnects performing the latter. It is usually desirable for a connector to be easy to visually, rapid to assemble, require only simple tooling. In some cases an equipment manufacturer might choose a connector specifically because it is not compatible with those other sources.
No single connector has all the properties, the proliferation of types is a reflection of differing requirements. Fretting is a failure mode in electrical connectors that have not been specifically designed to prevent it. Many connectors are keyed, with some mechanical component which prevents mating except with a correctly oriented matching connector, some connector housings are designed with locking mechanisms to prevent inadvertent disconnection or poor environmental sealing. Locking mechanism designs include locking levers of various sorts, screw locking, a terminal is a simple type of electrical connector that connects two or more wires to a single connection point. Wire nuts are another type of single point connector, terminal blocks provide a convenient means of connecting individual electrical wires without a splice or physically joining the ends. They are usually used to connect wiring among various items of equipment within an enclosure or to make connections among individually enclosed items.
Since terminal blocks are available for a wide range of wire sizes and terminal quantity. One type of terminal block accepts wires that are prepared only by removing a short length of insulation from the end, another type accepts wires that have ring or spade terminal lugs crimped onto the wires. Printed circuit board mounted terminal blocks allow individual wires to be connected to the circuit board, a general type of connector that simply screws or clamps bare wire to a post, such connectors are frequently used in electronic test equipment and audio. Many, but not all binding posts will accept a banana connector plug, since stripping the insulation from wires is time-consuming, many connectors intended for rapid assembly use insulation-displacement connectors so that insulation need not be removed from the wire
A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, known as the column, is the principal control device in the cockpit of many civilian and military aircraft. It often has supplementary switches to control aspects of the aircrafts flight. Joysticks are often used to video games, and usually have one or more push-buttons whose state can be read by the computer. A popular variation of the used on modern video game consoles is the analog stick. Joysticks are used for controlling machines such as cranes, underwater unmanned vehicles, surveillance cameras, miniature finger-operated joysticks have been adopted as input devices for smaller electronic equipment such as mobile phones. The name joystick is thought to originate with early 20th century French pilot Robert Esnault-Pelterie, there are competing claims on behalf of fellow pilots Robert Loraine, James Henry Joyce, and A. E. George. Loraine is cited by the Oxford English Dictionary for using the joystick in his diary in 1909 when he went to Pau to learn to fly at Bleriots school.
George was an aviator who with his colleague Jobling built. He is alleged to have invented the George Stick which became popularly known as the joystick. The George and Jobling aircraft control column is in the collection of the Discovery Museum in Newcastle upon Tyne, Joysticks were present in early planes, though their mechanical origins are uncertain. The coining of the term joystick may actually be credited to Loraine, as his is the earliest known usage of the term, the electrical two-axis joystick was invented by C. B. Mirick at the United States Naval Research Laboratory and patented in 1926, NRL was actively developing remote controlled aircraft at the time and the joystick was possibly used to support this effort. In the awarded patent, Mirick writes, My control system is applicable in maneuvering aircraft without a pilot. The Germans developed an electrical two-axis joystick around 1944, the joystick of the Kehl transmitter was used by an operator to steer the missile towards its target.
This joystick had on-off switches rather than analogue sensors, both the Hs 293 and Fritz-X used FuG230 Straßburg radio receivers in them to send the Kehls control signals to the ordnances control surfaces. A comparable joystick unit was used for the contemporary American Azon steerable munition and this German invention was picked up by someone in the team of scientists assembled at the Heeresversuchsanstalt in Peenemünde. Here a part of the team on the German rocket program was developing the Wasserfall missile, a variant of the V-2 rocket, the Wasserfall steering equipment converted the electrical signal to radio signals and transmitted these to the missile
Home computers were a class of microcomputers entering the market in 1977, and becoming common during the 1980s. They were marketed to consumers as affordable and accessible computers that, however, a home computer often had better graphics and sound than contemporaneous business computers. Their most common uses were playing games, but they were regularly used for word processing, doing homework. Home computers were usually not electronic kits, home computers were already manufactured in stylish metal or plastic enclosures. There were, commercial kits like the Sinclair ZX80 which were home and home-built computers since the purchaser could assemble the unit from a kit. For example, using a typical 1980s home computer as a home automation appliance would require the computer to be powered on at all times. Personal finance and database use required tedious data entry, by contrast, advertisements in the specialty computer press often simply listed specifications. Since most systems shipped with the BASIC programming language included on the system ROM, many users found programming to be a fun and rewarding experience, and an excellent introduction to the world of digital technology.
Often the only difference may be the outlet through which they are purchased. Another change from the computer era is that the once-common endeavour of writing ones own software programs has almost vanished from home computer use. As early as 1965, some projects such as Jim Sutherlands ECHO IV explored the possible utility of a computer in the home. In 1969, the Honeywell Kitchen Computer was marketed as a gift item, and would have inaugurated the era of home computing. Computers became affordable for the public in the 1970s due to the mass production of the microprocessor starting in 1971. Early microcomputers such as the Altair 8800 had front-mounted switches and diagnostic lights to control and indicate internal system status, while two early home computers could be bought either in kit form or assembled, most home computers were only sold pre-assembled. The keyboard - a feature lacking on the Altair - was usually built into the case as the motherboard. Ports for plug-in peripheral devices such as a display, cassette tape recorders, joysticks.
Usually the manufacturer would sell peripheral devices designed to be compatible with their computers as extra cost accessories, peripherals were not often interchangeable between different brands of home computer, or even between successive models of the same brand. To save the cost of a monitor, the home computer would often connect through an RF modulator to the family TV set
Centronics Data Computer Corporation was an American manufacturer of computer printers, now remembered primarily for the parallel interface that bears its name. Centronics began as a division of Wang Laboratories and initially operated by Robert Howard and Samuel Lang, the group produced remote terminals and systems for the casino industry. Printers were developed to print receipts and transaction reports, Wang spun off the business in 1971 and Centronics was formed as a corporation in Hudson, New Hampshire with Howard as president and chairman. The Centronics Model 101 was introduced at the 1970 National Computer Conference, the print head used an innovative seven-wire solenoid impact system. Based on this design, Centronics made the claim to have developed the first dot matrix impact printer, a business relationship developed when Centronics needed reliable manufacturing of the printer mechanisms—a relationship that would help propel Brother into the printer industry. Hugel would become vice president of Centronics.
Print heads and electronics were built in Centronics plants in New Hampshire and Ireland, mechanisms were built in Japan by Brother, in the 1970s, Centronics formed a relationship with Canon to develop non-impact printers. No products were produced, but Canon continued to work on laser printers. In 1977, Centronics sued competitor Mannesmann AG in a patent dispute regarding the spring used in the print actuator. In 1975, Centronics formed an OEM agreement with Tandy and produced DMP, the 6000 series band printers were introduced in 1978. By 1979 company revenues were over $100 million, in 1980, the Mini-Printer Model 770 was introduced—a small, low-cost desktop serial matrix printer. This was the first printer built completely in-house, and there were problems, flaws in the microprocessor led to a recall and a stoppage of manufacturing for a year. During this period, Epson and others began to market share. 1980 saw the introduction of the E Series 900 and 1200 LPM band printers, in 1982, Control Data Corporation merged their current printer business unit, CPI, into Centronics and at the same time invested $25 million in the company, effectively taking control from Howard.
Control Data controlled the company until 1986 when CDCs interest was acquired by a group of investors affiliated with Drexel Burnham Lambert, the Drexel interest was acquired by Centronics in 1987. The LineWriter 400 band printer was introduced in 1983, closely followed by the faster LineWriter 800 band printer in 1984, the LineWriter series would continue through 1995. The GLP was a series of low-end serial matrix printers introduced in 1984, the relationship with Brother continued with several of the PrintStation models being produced from rebadged Brother products. Exclusive rights to market Trilog color matrix printers was acquired in 1984, advanced Terminals and BDS Computer Australia Pty Ltd were purchased in 1986
Sinclair Research Ltd is a British consumer electronics company founded by Clive Sinclair in Cambridge. In 1980, Clive Sinclair entered the computer market with the ZX80 at £99.95. In 1982 the ZX Spectrum was released, becoming the UKs best selling computer, Sinclair Research Ltd still exists as a one-man company, continuing to market Clive Sinclairs inventions. On 25 July 1961, Clive Sinclair founded his first company, the company developed hi-fi products, radios and scientific instruments. When it became clear that Radionics was failing, Sinclair took steps to ensure that he would be able to continue to pursue his commercial goals, in February 1975, he changed the name of Ablesdeal Ltd to Westminster Mail Order Ltd. The name was changed to Sinclair Instrument Ltd in August 1975, the companys first product was a watch-like Wrist Calculator. In July 1977, Sinclair Instrument Ltd was renamed Science of Cambridge Ltd, around the same time, Ian Williamson showed Chris Curry a prototype microcomputer based on a National Semiconductor SC/MP microprocessor and parts from a Sinclair calculator.
Curry was impressed and encouraged Sinclair to adopt it as a product, in June 1978, Science of Cambridge launched its MK14 microcomputer in kit form. In May 1979, Jim Westwood, Sinclairs chief engineer, designed a new microcomputer based on the Zilog Z80 microprocessor, Sinclair Instrument Ltd introduced the computer as the ZX80 in February 1980, as both a kit and ready-built. In November 1979, Science of Cambridge Ltd was renamed Sinclair Computers Ltd, in March 1981, Sinclair Computers was renamed Sinclair Research Ltd and the Sinclair ZX81 was launched. In February 1982, Timex Corporation obtained a license to manufacture, in April the ZX Spectrum was launched. In July Timex launched the TS1000 in the United States, in March 1982 Sinclair Research Ltd made an £8. 55m profit on turnover of £27. 17m, including a £383,000 government grant to develop a flat screen. In 1982 Clive Sinclair converted the Barker & Wadsworth mineral water bottling factory at 25 Willis Road, Cambridge, in January 1983 the ZX Spectrum personal computer was presented at the Las Vegas Consumer Electronics Show.
In September the Sinclair TV80 pocket television was launched, but was a commercial failure, in 1983 the company bought Milton Hall in the village of Milton, for £2m, establishing its MetaLab research and development facility there. In late 1983 Timex decided to out of the Timex Sinclair venture which. However, Timex computers continued to be produced for years in other countries. Timex Portugal launched improved versions, the TS2048 and 2068, that developed and launched the FDD3000. The Sinclair QL was announced on 12 January 1984, shortly before the Apple Macintosh went on sale, the QL was nowhere near as successful as Sinclairs earlier computers
A computer network or data network is a telecommunications network which allows nodes to share resources. In computer networks, networked computing devices exchange data with other using a data link. The connections between nodes are established using either cable media or wireless media, the best-known computer network is the Internet. Network computer devices that originate and terminate the data are called network nodes, nodes can include hosts such as personal computers, servers as well as networking hardware. Two such devices can be said to be networked together when one device is able to exchange information with the other device, Computer networks differ in the transmission medium used to carry their signals, communications protocols to organize network traffic, the networks size and organizational intent. In most cases, application-specific communications protocols are layered over other more general communications protocols and this formidable collection of information technology requires skilled network management to keep it all running reliably.
The chronology of significant computer-network developments includes, In the late 1950s, in 1960, the commercial airline reservation system semi-automatic business research environment went online with two connected mainframes. Licklider developed a group he called the Intergalactic Computer Network. In 1964, researchers at Dartmouth College developed the Dartmouth Time Sharing System for distributed users of computer systems. The same year, at Massachusetts Institute of Technology, a group supported by General Electric and Bell Labs used a computer to route. Throughout the 1960s, Leonard Kleinrock, Paul Baran, and Donald Davies independently developed network systems that used packets to transfer information between computers over a network, in 1965, Thomas Marill and Lawrence G. Roberts created the first wide area network. This was an precursor to the ARPANET, of which Roberts became program manager. Also in 1965, Western Electric introduced the first widely used telephone switch that implemented true computer control, in 1972, commercial services using X.25 were deployed, and used as an underlying infrastructure for expanding TCP/IP networks.
In July 1976, Robert Metcalfe and David Boggs published their paper Ethernet, Distributed Packet Switching for Local Computer Networks, in 1979, Robert Metcalfe pursued making Ethernet an open standard. In 1976, John Murphy of Datapoint Corporation created ARCNET, a network first used to share storage devices. In 1995, the transmission speed capacity for Ethernet increased from 10 Mbit/s to 100 Mbit/s, by 1998, Ethernet supported transmission speeds of a Gigabit. Subsequently, higher speeds of up to 100 Gbit/s were added, the ability of Ethernet to scale easily is a contributing factor to its continued use. Providing access to information on shared storage devices is an important feature of many networks, a network allows sharing of files and other types of information giving authorized users the ability to access information stored on other computers on the network
Floppy disks are read and written by a floppy disk drive. Floppy disks, initially as 8-inch media and in 5¼-inch and 3½-inch sizes, were a form of data storage and exchange from the mid-1970s into the mid-2000s. These formats are usually handled by older equipment and these disks and associated drives were produced and improved upon by IBM and other companies such as Memorex, Shugart Associates, and Burroughs Corporation. The term floppy disk appeared in print as early as 1970, in 1976, Shugart Associates introduced the first 5¼-inch FDD. By 1978 there were more than 10 manufacturers producing such FDDs, there were competing floppy disk formats, with hard- and soft-sector versions and encoding schemes such as FM, MFM and GCR. The 5¼-inch format displaced the 8-inch one for most applications, the most common capacity of the 5¼-inch format in DOS-based PCs was 360 kB and in 1984 IBM introduced the 1.2 MB dual-sided floppy disk along with its PC-AT model. IBM started using the 720 kB double-density 3½-inch microfloppy disk on its Convertible laptop computer in 1986 and these disk drives could be added to older PC models.
In 1988 IBM introduced a drive for 2.88 MB DSED diskettes in its top-of-the-line PS/2 models, throughout the early 1980s, limitations of the 5¼-inch format became clear. Originally designed to be practical than the 8-inch format, it was itself too large, as the quality of recording media grew. A number of solutions were developed, with drives at 2-, 2½-, 3-, 3½-, the large market share of the 5¼-inch format made it difficult for these new formats to gain significant market share. A variant on the Sony design, introduced in 1982 by a number of manufacturers, was rapidly adopted. By the end of the 1980s, 5¼-inch disks had been superseded by 3½-inch disks, by the mid-1990s, 5¼-inch drives had virtually disappeared, as the 3½-inch disk became the predominant floppy disk. Floppy disks became ubiquitous during the 1980s and 1990s in their use with computers to distribute software, transfer data. Before hard disks became affordable to the population, floppy disks were often used to store a computers operating system.
Most home computers from that period have a primary OS and BASIC stored as ROM, by the early 1990s, the increasing software size meant large packages like Windows or Adobe Photoshop required a dozen disks or more. In 1996, there were a five billion standard floppy disks in use. Then, distribution of packages was gradually replaced by CD-ROMs, DVDs. External USB-based floppy disk drives are available, many modern systems provide firmware support for booting from such drives
In computing, a printer is a peripheral which makes a persistent human-readable representation of graphics or text on paper or similar physical media. The worlds first computer printer was a 19th-century mechanically driven apparatus invented by Charles Babbage for his difference engine, the plotter was used for those requiring high quality line art like blueprints. Laser printers using PostScript mixed text and graphics, like dot-matrix printers, by 1990, most simple printing tasks like fliers and brochures were now created on personal computers and laser printed, expensive offset printing systems were being dumped as scrap. The HP Deskjet of 1988 offered the same advantages as laser printer in terms of flexibility, inkjet systems rapidly displaced dot matrix and daisy wheel printers from the market. By the 2000s high-quality printers of this sort had fallen under the price point. Even the desire for printed output for offline reading while on mass transit or aircraft has been displaced by e-book readers, traditional printers are being used more for special purposes, like printing photographs or artwork, and are no longer a must-have peripheral.
Starting around 2010, 3D printing became an area of intense interest and these devices are in their earliest stages of development and have not yet become commonplace. Personal printers are designed to support individual users, and may be connected to only a single computer. These printers are designed for low-volume, short-turnaround print jobs, requiring minimal setup time to produce a copy of a given document. However, they are generally slow devices ranging from 6 to around 25 pages per minute, this is offset by the on-demand convenience. Some printers can print documents stored on cards or from digital cameras. Networked or shared printers are designed for high-volume, high-speed printing and they are usually shared by many users on a network and can print at speeds of 45 to around 100 ppm. The Xerox 9700 could achieve 120 ppm, a virtual printer is a piece of computer software whose user interface and API resembles that of a printer driver, but which is not connected with a physical computer printer.
It is called a printer by analogy with a printer which produces a two-dimensional document by a similar process of depositing a layer of ink on paper. The choice of print technology has an effect on the cost of the printer and cost of operation, speed and permanence of documents. Some printer technologies dont work with certain types of physical media, cheques can be printed with liquid ink or on special cheque paper with toner anchorage so that alterations may be detected. The machine-readable lower portion of a cheque must be printed using MICR toner or ink and other clearing houses employ automation equipment that relies on the magnetic flux from these specially printed characters to function properly. The following printing technologies are found in modern printers, A laser printer rapidly produces high quality text
The Netherlands, informally known as Holland is the main constituent country of the Kingdom of the Netherlands. It is a densely populated country located in Western Europe with three territories in the Caribbean. The European part of the Netherlands borders Germany to the east, Belgium to the south, and the North Sea to the northwest, sharing borders with Belgium, the United Kingdom. The three largest cities in the Netherlands are Amsterdam and The Hague, Amsterdam is the countrys capital, while The Hague holds the Dutch seat of parliament and government. The port of Rotterdam is the worlds largest port outside East-Asia, the name Holland is used informally to refer to the whole of the country of the Netherlands. Netherlands literally means lower countries, influenced by its low land and flat geography, most of the areas below sea level are artificial. Since the late 16th century, large areas have been reclaimed from the sea and lakes, with a population density of 412 people per km2 –507 if water is excluded – the Netherlands is classified as a very densely populated country.
Only Bangladesh, South Korea, and Taiwan have both a population and higher population density. Nevertheless, the Netherlands is the worlds second-largest exporter of food and agricultural products and this is partly due to the fertility of the soil and the mild climate. In 2001, it became the worlds first country to legalise same-sex marriage, the Netherlands is a founding member of the EU, Eurozone, G-10, NATO, OECD and WTO, as well as being a part of the Schengen Area and the trilateral Benelux Union. The first four are situated in The Hague, as is the EUs criminal intelligence agency Europol and this has led to the city being dubbed the worlds legal capital. The country ranks second highest in the worlds 2016 Press Freedom Index, the Netherlands has a market-based mixed economy, ranking 17th of 177 countries according to the Index of Economic Freedom. It had the thirteenth-highest per capita income in the world in 2013 according to the International Monetary Fund, in 2013, the United Nations World Happiness Report ranked the Netherlands as the seventh-happiest country in the world, reflecting its high quality of life.
The Netherlands ranks joint second highest in the Inequality-adjusted Human Development Index, the region called Low Countries and the country of the Netherlands have the same toponymy. Place names with Neder, Nieder and Nedre and Bas or Inferior are in use in all over Europe. They are sometimes used in a relation to a higher ground that consecutively is indicated as Upper, Oben. In the case of the Low Countries / the Netherlands the geographical location of the region has been more or less downstream. The geographical location of the region, changed over time tremendously
The ZX Spectrum is an 8-bit personal home computer released in the United Kingdom in 1982 by Sinclair Research Ltd. It was manufactured in Dundee, Scotland, in the now closed Timex factory, the Spectrum was among the first mainstream-audience home computers in the UK, similar in significance to the Commodore 64 in the USA. Licensing deals and clones followed, and earned Clive Sinclair a knighthood for services to British industry, the Commodore 64, Dragon 32, Oric-1 and Atmos, BBC Microcomputer and the Amstrad CPC range were rivals to the Spectrum in the UK market during the early 1980s. Over 24,000 software titles have been released since the Spectrums launch, in 2014, a Bluetooth keyboard modelled on the Spectrum was announced. The Spectrum is based on a Zilog Z80 A CPU running at 3.5 MHz, the original model has 16 KB of ROM and either 16 KB or 48 KB of RAM. Hardware design was by Richard Altwasser of Sinclair Research, and the appearance was designed by Sinclairs industrial designer Rick Dickinson.
Video output is through an RF modulator and was designed for use with contemporary portable television sets, the image resolution is 256×192 with the same colour limitations. To conserve memory, colour is stored separate from the bitmap in a low resolution, 32×24 grid overlay. In practice, this means that all pixels of an 8x8 character block share one foreground colour, Altwasser received a patent for this design. An attribute consists of a foreground and a colour, a brightness level and a flashing flag which. This scheme leads to what was dubbed colour clash or attribute clash and this became a distinctive feature of the Spectrum, meaning programs, particularly games, had to be designed around this limitation. Other machines available around the time, for example the Amstrad CPC or the Commodore 64. The Commodore 64 used colour attributes in a way, but a special multicolour mode, hardware sprites. Sound output is through a beeper on the machine itself, capable of producing one channel with 10 octaves, software was available that could play two channel sound.
The machine includes an expansion bus edge connector and 3.5 mm audio in/out ports for the connection of a recorder for loading and saving programs. The ear port can drive headphones and the mic port provides line level audio out which could be amplified, the machines Sinclair BASIC interpreter is stored in ROM and was written by Steve Vickers on contract from Nine Tiles Ltd. The Spectrums chiclet keyboard is marked with BASIC keywords, for example, pressing G when in programming mode would insert the BASIC command GO TO. The ZX Spectrum character set was expanded from that of the ZX81, Spectrum BASIC included extra keywords for the more advanced display and sound, and supported multi-statement lines