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Hardware & Input/Output (I/O) Devices

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Hardware & Input/Output (I/O) Devices

  1. 1. Hardware Input/Output (I/O) Devices Instructor : Muhammad Hammad Waseem Email: m.hammad.wasim@gmail.com Course : Introduction to Computer 1
  2. 2. Hardware  Hardware is a comprehensive term for all of the physical parts of a computer.  All the input and output devices of the computer lies in hardware. 2 M.Hammad Waseem
  3. 3. Input Devices  Input device captures information and translates it into a form that can be processed and used by other parts of your computer.  In computing, an input device is any peripheral (piece of computer hardware) used to provide data and control signals to a computer or other Systems.(Wikipedia)  The computer follows the instructions given to it by an input device.  A variety of input devices are used with the computer depending on the type and purpose of input information.  For example, a keyboard is commonly used to transfer data or information from human readable form to machine readable form. 3 M.Hammad Waseem
  4. 4. Examples of Input Devices  Keyboards  Pointing devices  Scanners  Game controllers  Microphones  Digital cameras  Webcams  Styluses  Barcode reader etc 4 M.Hammad Waseem
  5. 5. Keyboard  A keyboard is the most commonly used input device which helps us in simply keying in required information in a computer.  A keyboard can be used effectively to communicate with the computer but considered to be relatively slow as compared to other input devices.  The keyboard is divided into following divisions:  ALPHABETIC KEYPAD  These keys are similar to a standard typewriter and is used to type general information. 5 M.Hammad Waseem
  6. 6. Keyboard (cont.…)  NUMBERIC KEYPAD  These keys are used to input numeric data only. These are very useful in case of large numeric data input because all numeric keys can be accessed by one hand only. These keys can also be used as an alternative to the screen navigation and editing keys.  FUNCTION KEYS  These are keys marked as F1 - F12, located normally at the top of the keyboard.  Each of these function keys are given some special function in different packages.  SCREEN NAVIGATION AND EDITING KEYS  These keys are provided to move around in the screen. May programs use these keys to let the user move around the screen display. In some keyboards these keys are also provided inside the numeric keypad as alternate keys. 6 M.Hammad Waseem
  7. 7. Parts of Keyboard 7 M.Hammad Waseem
  8. 8. Mouse  The mouse is an input device that usually contains one or two buttons.  The mouse is used to control the on-screen pointer by pointing and clicking, double-clicking, or dragging objects on the screen.  As a user moves the mouse on a flat surface, the mouse controls the cursor movement on the screen.  When the user presses one of the buttons, the mouse either marks a place on the screen or makes selection from data or menu on the screen.  A mouse can be used for many application, ranging from games to drawing and designing products with computer graphics. 8 M.Hammad Waseem
  9. 9. Scanner  Scanner is an input device. It is also called Optical Reader or Digital Scanner.  Scanner scans or reads text and picture printed on a paper and enters them directly into the computer memory.  The advantage of a scanner is that the user needs not type the input data in.  The scanner takes electronic images, of text or pictures from the paper and stores them into the computer.  Optical Character Recognition (OCR) software translates the scanned document into text that can be edited. 9 M.Hammad Waseem
  10. 10. Game Controllers  Game controllers are used mainly to play games  Types of gaming devices  Gamepads  Joysticks  Gaming wheels 10 M.Hammad Waseem
  11. 11. Microphone  Microphone allows the user to record sounds as input to their computer.  Speech recognition is increasingly being included in application software therefore the use of microphone is also increased.  Microphone can be used individually and also used with the headphone. 11 M.Hammad Waseem
  12. 12. Digital Cameras  Digital cameras are used to:  Download images to a computer  Post pictures to the Web  Produce videos  Resolution is measured in megapixels/  Higher the resolution, better the image quality, but the more expensive the camera. 12 M.Hammad Waseem
  13. 13. Web Cam  Web cam is a video camera that can be used to take images for uploading to the Web.  A webcam is a video camera that feeds its images in real time to a computer. (Wikipedia) 13 M.Hammad Waseem
  14. 14. Stylus  A Stylus is an input device consisting of a thin stick that uses pressure to enter information or to click and point.  Styluses are used with:  PDAs  Tablet PCs  Graphics tablets 14 M.Hammad Waseem
  15. 15. Barcode Reader  An input device that converts a pattern of printed bars into a number that a computer can read.  They are often used by businesses to quickly input price and product information. 15 M.Hammad Waseem
  16. 16. Question Answer Session…. 1. Most commonly used input device is___? 2. The keyboard is divided into ___ divisions? 3. Pointing device which we have studied so far? 4. Scanner is an ___device. It is also called___? 5. Which software translates the scanned document into text? 6. Types of gaming devices? 7. Resolution is measured in ___? 8. Web cam is used for? 9. What is stylus? 10. What is barcode? 16 M.Hammad Waseem
  17. 17. Output Devices  Output Devices take information within your computer and present it to you in a form that you can understand. OR  The devices which are used to display the data to the user either in the form of hard copy or soft copy are called Output Devices. OR  An Output Device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) (Wikipedia)  The output devices gives us output in two form  Hardcopy  Softcopy 17 M.Hammad Waseem
  18. 18. Output Devices (Cont.…) Hard Copy:  Hard Copy is a permanent copy, in the form of a physical object.  Like print out on the paper. Soft Copy:  A Soft Copy is an electronic copy of some type of data, such as a file viewed on a computer's display (Screen).  Examples of Output Devices are:  Monitors  Printers  Speakers  Plotters 18 M.Hammad Waseem
  19. 19. Monitors (Computer Display)  To display result or output from computer, a T.V like device is used which is called monitor.  The monitors are also referred as C.R.T (Cathode Ray Tube), V.D.U (Visual Display Unit).  The monitor assist during input from the keyboard, this display is called a soft copy.  The monitor can be of various kinds, depending on the type of application.  Monitors are categorized into two groups:  Monochrome monitors  Color monitors 19 M.Hammad Waseem
  20. 20. Monitors (Cont.…) Monochrome Monitor  A monochrome monitor has two colors, one for foreground and the other for background. The colors can be white, amber or green on a dark (black) background.  The monochrome monitors display both text and graphics modes. Color Monitors  Color monitors implement the RGB color model by using three different phosphors that appear Red, Green, and Blue when activated.  A color monitor displays more than two colors. Color monitors have been developed through the following paths.  Enhance Graphic Array (EGA),  Colour Graphic Array (CGA),  Video Graphics Array (VGA),  Super Video Graphics Array (SVGA). 20 M.Hammad Waseem
  21. 21. Forms of Monitor  There are two forms of monitor:  Cathode-Ray Tubes (CRTs)  Flat-panel Display. Cathode Ray Tubes (CRT)  The CRT monitors are a lot like television set, using the same CRT or Cathode Ray Tube technology.  The CRT monitor has two major parts;  the screen and  the cathode ray tube (CRT).  The screen is the front of the monitor and CRT is fitted inside the monitor. 21 M.Hammad Waseem
  22. 22. Forms of Monitor (Cont.…) Flat Panel Displays  Portable computers such as a laptop use flat panel displays, because they are more compact and consume less power than CRTs.  Portable computers use several kinds of flat panel screens:  Liquid-Crystal Displays (LCDs)  Electroluminescent (EL) Displays  Gas Plasma Displays 22 M.Hammad Waseem
  23. 23. Forms of Monitor (Cont.…) Liquid-Crystal Displays (LCDs)  A display technology that creates characters by means of reflected light and is commonly used in digital watches and laptop computers.  LCDs replaced LEDs (light emitting diodes) because LCDs are difficult to read in a strong light, because they do not emit their own light. 23 M.Hammad Waseem
  24. 24. Forms of Monitor (Cont.…) Electroluminescent (EL) Displays  A flat panel display technology that actively emits light at each pixel when it is electronic charged.  This provides a sharp, clear image and wide viewing angle.  The EL display type of flat panel is better than LCD. Gas Plasma Displays  This is also called a gas panel or a plasma panel and is another flat screen technology.  A plasma panel contains a grid of electrodes in a flat, gas filled panel.  The image can persist for a long time without refreshing in this panel.  The disadvantages of the gas plasma displays are that they must use AC power and cannot show sharp contrast. 24 M.Hammad Waseem
  25. 25. Printers  A printer is an output device that produces a hard copy of data. The resolution of printer output is expressed as DPI.  Printer can be categorized in several ways the most common distinction is  Impact and  Non-Impact. 25 M.Hammad Waseem
  26. 26. IMPACT PRINTING NON – IMPACT PRINTING 26 Printers  Is the method used by the conventional type writers.  In some type of impact printing a metal “hammer” embossed with a character strikes a print ribbon, which presses the characters image into paper.  No physical contact at all occurs between the printing mechanism and the paper. The most popular non- impact methods today utilize thermal transfer, ink- jet. M.Hammad Waseem
  27. 27. Types of Printers Dot Matrix Printer  Dot-matrix printers are printers that write characters and form graphic images using one or two columns of tiny dots on a print head.  The dot hammer moving serially across the paper strikes an inked-ribbon and creates images on paper.  The quality of output from a dot matrix printer depends largely on the number of dots in the matrix.  Dot matrix printers are often categorized by the number of pins in the printer head typically, 9 or 24. Several kinds of dot matrix printers are available with print heads that have 7, 9, 18, or 24 pins. 27 M.Hammad Waseem
  28. 28. Types of Printers (Cont.…) Daisy-Wheel Printer  Daisy wheel printer are some times called letter quality printer because they are often used to produce attractive correspondence.  The D.W.P is a flat circular device made of metal with character embossed on it. As this wheel spins at a very high speed the hammer hits the specific character against the ribbon which presses against the paper. 28 M.Hammad Waseem
  29. 29. Types of Printers (Cont.…) Line Printers  Any printer that prints one line at one time, as opposed to one character at a time or one page at a time.  They are high speed devices and are often used with mainframes, minicomputers, or networked machines rather than with single user system.  Types of line printers include  chain printers.  band printer.  Line printers are very reliable and can speed up to 3000 lines per minute (LPM). 29 M.Hammad Waseem
  30. 30. Types of Printers (Cont.…) Ink-Jet Printer  Ink-jet is a printer mechanism that sprays one or more color of ink at high speed onto the paper and produces high-quality printing.  This printer also produces color printing as well as high- quality image.  Ink-jet printers can be used for variety of color printing at a relatively low cost.  Ink-jet printing has two methods:  Continuous stream method  Drop-on- demand method. 30 M.Hammad Waseem
  31. 31. Types of Printers (Cont.…) Laser Printers  An electrophotographic printer that is based on the technology used by photocopiers.  Laser printer resolution is typically from 300 to 1200 dpi, but specialty printers can reach imagesetter resolution of 2400 dpi.  Low-end laser printers print in the 4 to 8 ppm range, while typical office workgroup units print 17 to 32 ppm.  Midrange units print in the 40-60 ppm range.  High-end printers that print from 150 to more than 1,000 ppm. 31 Working of Laser Printer M.Hammad Waseem
  32. 32. Speakers  A device containing a transducer that converts electrical signals (electric current) into sound waves (acoustic energy) for the production of sound.  This device produces a human speech like sound, but actually is prerecorded vocalized sounds. 32 M.Hammad Waseem
  33. 33. Plotter  Plotter is a special output device, which is used to produce high quality, perfectly proportional hard copy output.  Plotters are designed to produce large drawings or images such as construction plans for buildings or blue prints for mechanical devices.  A plotter is composed of a pen, a move-able carriage, a drum and a holder for chart paper.  Both the pen and the paper can move up and down and back and forth. This permits very detailed drawings.  There are two types of plotters, which are as follows:  Drum Plotter  Flatbed Plotter 33 M.Hammad Waseem
  34. 34. Plotter (Cont.…) DRUM PLOTTER  On the drum plotter, the pens, and the drum move concurrently in different axes to produce the image.  Drum plotters are used to produce continuous output, such as plotting earthquake activity, or for long graphic output, such as structural view of a skyscraper. FLATBED PLOTTER  On some flatbed plotters, the pen moves in both axes while the paper remains stationary.  However, on most desktop plotters, both paper and pen move concurrently in much the same way as on drum plotters. 34 M.Hammad Waseem
  35. 35. 35 Plotter (Cont.…) Drum Plotter Flatbed Plotter M.Hammad Waseem
  36. 36. Question Answer Session…. 1. Define output devices. 2. What is diff. b/w hard and softcopy? 3. Name Forms of monitor? 4. RGB stands for? 5. Define monochrome monitor. 6. CRT & LCD stands for? 7. Printers are categories into__ divisions? 8. How many no. of pins are used in Dot matrix printers? 9. What is the Speed of Line printers in (LPM)? 10. There are two types of plotters, which are? 11. Diff. b/w drum & flatbed plotters. 36 M.Hammad Waseem

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