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Input devicesSome input devices are :•Keyboards•Track point•Mouse•Barcode reader•Touch screens
keyboardsIn computing, a keyboard uses an arrangement of buttonsor keys, to act as mechanical levers or electronic switches. Thekeyboards became the main input device for computer.Advantages:•Most computers come with a keyboard.•People are used to using keyboards to enter data.•A skilled typist can enter data very quickly.Disadvantages:•It is easy to make mistakes when typing in data.•If you can’t touch type, it can take time to enter data.•Keyboards are not suitable for creating diagrams.
Track PointA Track Point, is a cursor control device found in IBMthink pad, notebook, computers.Advantages :•It requires no extra space, since it is inbuilt withinthe keyboard. Thus , it is ideal were little or no spaceis available.Disadvantages:•It takes a practice in order to learn how tocoordinate the correct amount of pressure on thetrack point.
MouseA mouse controls a pointer on the monitor. It enables you to controlwhat happens on the screen by moving the mouse on your desktopand pointing, clicking and selecting items on the screen.Advantages :•Ideal for use with desktop computers.•Works well in conjunction with a keyboard for data entry.•Using a mouse to select items on the screen is faster than using akeyboard.Disadvantages:•It is not easy to input text while using a mouse.•They need a flat space close to the computer.•Overuse can lead to repetitive strain injurey.
Barcode ReaderBarcode readers are like scanners which use laser beams in order toread barcodes. A barcode reader is used to read the barcode byusing a visible red light.Advantages :•The process of data entry is fast and accurate.•Barcodes can be printed by normal printing methods.•No need to write down the name of the item and its price- allare retrieved automatically.Disadvantages:•If there is dirt or any marks on the barcode, then the barcodereader may be unable to read it.•Only numbers can be coded.
Touch ScreensA touch screen is an input device because it allows the user touse his/her finger in order to touch the preferred option. Advantages: •No training is required. •No extra peripherals such as mouse are needed. Disadvantages: •Not ideal to put in large amounts of data. •Not very accurate. •Only the items already on the screen can be selected. •Not robust-can soon become faulty if misused
Output devicesAn example of an output Is a printer but there are different types ofprinters:•Character printer : prints one character at a time.•Page printer: prints one page at a time•Line printer: prints one line at a time.
Character printerIn character printers there are different groups such asimpact and non-impact. Also there are different types ofeach groups. Impact non-impact dot matrix thermal Daisy wheel inkjet Golf ball
Impact printers Golf ball printer : a golf ball printer uses a rotating ball as a head. On the surface of this ball, there are letters and when this ball strikes the ribbon, the character is imprinter on the paper Daisy wheel printer : the daisy wheel printer uses a wheel as its print head. These are character shapes formed on each spoke of the wheel. The wheel is rotated until the required character is found, and then a hammer strikes the spoke onto the ribbon against the paperAdvantages : Diasdvantages:You can change fonts you have to change wheel to change fonts.Relatively good quality slow noisy no graphics
Impact printers Dot matrix printer : the dot matrix printer has a number of pins in its head. These pins are configured in such a way so as to form a shape. These pins hit the ribbon into the paper. Thus, all character are made up of a pattern of dots. The more pins the better the resolutionAdvantages : disadvantages:Cheap simple graphicsEasy maintenance low qualityCan print graphics slow noisy
Non- impact printersThermal printer: thermal printers work by heating certain areasof the thermal paper. When this paper passes over the thermalprint head, the paper turns black at heated areas, thusproducing a printed image.Inkjet printer : inkjet printers work by placing extremely smalldroplets of ink onto the paper, thus creating an image/character Advantages : disadvantages : Quiet good quality paper needed Fast ink may be smudged Cheap Good quality
Page printerIn page printers there is only one group and that is non-impact. In the non-impact group there Is one printer andthat is laser printer.Laser printer : A laser printer is a common typeof computer printer that rapidly produces high qualitytext and graphics on plain paper.Advantages: disadvantages:High quality of printouts colour laser printers are expensiveFast: they print 1 page at time expensive maintenanceQuiet : no impact
Line printerA line printer has one group : impact printer . The impact printer isdivided into two the drum printer and the chain printer. Drum printer : drum printers use a rotating drum with character shaped on it. This printer also consists of a hammer set, where there Is a hammer for each character position on the line. these hammers hit the paper onto the ribbon and presses it against the drum. This type of printer is used for checking printing.
Line printerChain printer : chain printers use a chain with character shapedon it. This chain rotates and the hammer strikes the paper ontothat character as it passes. This type of printer is commonly usedfor payroll listing. Advantages : disadvantages: Fast can’t print graphics Reliable Can handle large volumes of printouts