Computer Lecture 2


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Computer Lecture 2

  1. 1. INPUT DEVICES <ul><li>Input devices accept data and instructions from the user or from another computer system. The keyboard and mouse are examples of input devices. </li></ul>
  2. 3. TYPES OF INPUT DEVICES <ul><li>Keyboard </li></ul><ul><li>Mouse </li></ul><ul><li>Punched cards </li></ul><ul><li>Optical Character Readers (OCR) </li></ul><ul><li>Barcode Reader </li></ul><ul><li>Pens </li></ul><ul><li>Touch Screen </li></ul>
  3. 4. KEYBOARD <ul><li>The Standard Keyboard Layout. </li></ul><ul><li>How a Keyboard Works. </li></ul>
  4. 5. STANDARD KEYBOARD LAYOUT <ul><li>A standard computer keyboard has about 100 keys. </li></ul><ul><li>Most keyboards use the QWERTY layout, named for the first six keys in the top row of letters. </li></ul>
  5. 7. HOW A KEYBOARD WORKS <ul><li>When you press a key: </li></ul><ul><li>The keyboard controller detects the keystroke. </li></ul><ul><li>The controller places a scan code in the keyboard buffer, indicating which key was pressed. </li></ul><ul><li>The keyboard sends the computer an interrupt request, telling the CPU to accept the keystroke. </li></ul>
  6. 9. WHAT IS A MOUSE? <ul><li>The mouse is a pointing device. You use it to move a graphical pointer on the screen. </li></ul><ul><li>The mouse can be used to issue commands, draw, and perform other types of input tasks. </li></ul>
  7. 10. MOUSE TECHNIQUES <ul><li>Using the mouse involves five techniques: </li></ul><ul><ul><li>Pointing; Move the mouse to move the on-screen pointer. </li></ul></ul><ul><ul><li>Clicking; Press and release the left mouse button once. </li></ul></ul><ul><ul><li>Double-clicking; Press and release the left mouse button twice. </li></ul></ul><ul><ul><li>Dragging; Hold down the left mouse button as you move the pointer. </li></ul></ul><ul><ul><li>Right-clicking; Press and release the right mouse button. </li></ul></ul>
  8. 11. VARIANTS OF THE MOUSE <ul><li>Trackballs </li></ul><ul><li>Trackpads </li></ul><ul><li>Integrated Pointed Devices </li></ul>
  9. 12. TRACKBALLS <ul><li>A trackball is like a mouse turned upside-down. </li></ul><ul><li>Use your thumb to move the exposed ball and your fingers to press the buttons. </li></ul>Many styles of trackball are available.
  10. 13. TRACKPADS <ul><li>A trackpad is a touch-sensitive pad that provides the same functionality as a mouse. </li></ul><ul><li>To use a trackpad, you glide your finger across its surface. </li></ul><ul><li>Trackpads provide a set of buttons that function like mouse buttons. </li></ul>
  11. 15. DEVICES FOR THE HAND <ul><li>Pens </li></ul><ul><li>Touch Screens </li></ul><ul><li>Game Controllers </li></ul>
  12. 16. The user can point, tap, draw and write on the computer’s screen with a pen.
  13. 17. TOUCH SCREEN
  14. 18. Bar code readers commonly track sales in retail stores
  15. 19. OUTPUT DEVICES <ul><li>Types of output devices </li></ul><ul><ul><li>Monitors </li></ul></ul><ul><ul><li>PC Projectors </li></ul></ul><ul><ul><li>The most commonly used types of printers </li></ul></ul><ul><ul><li>Speakers </li></ul></ul>
  16. 20. MONITORS <ul><li>CRT Monitors </li></ul><ul><li>Flat-Panel Monitors </li></ul><ul><li>Comparing Monitors </li></ul><ul><li>Video Controllers </li></ul>
  17. 21. PC PROJECTORS <ul><li>A PC projector connects to a PC and is used to project images on a large screen. </li></ul><ul><li>Many PC projectors provide the same resolutions and color levels as high-quality monitors. </li></ul><ul><li>Digital light processing (DLP) projectors use a microchip containing tiny mirrors to produce very sharp, bright images. </li></ul>
  18. 22. Projected Screen
  19. 23. SOUND SYSTEMS <ul><li>Multimedia PCs come with a sound card, speakers, and a CD-ROM or DVD drive. </li></ul><ul><li>A sound card translates digital signals into analog ones that drive the speakers. </li></ul><ul><li>With the right software, you can use your PC to edit sounds and create special sound effects. </li></ul>
  20. 25. TYPES OF PRINTERS <ul><li>Dot matrix </li></ul><ul><li>Ink jet </li></ul><ul><li>Laser </li></ul>
  21. 26. DOT MATRIX <ul><li>The paper is pressed against a drum (a rubber-coated cylinder) and is intermittently pulled forward as printing progresses. </li></ul><ul><li>The electromagnetically-driven print head moves across the paper and strikes the printer ribbon situated between the paper and print head pin. </li></ul><ul><li>The impact of the print head against the printer ribbon imprints ink dots on the paper which form human-readable characters. </li></ul><ul><li>It is ideal for environments that frequently print on carbon copy. </li></ul>
  22. 28. INKJET PRINTERS <ul><li>The relative low cost of the printers and multi-purpose printing abilities make it a good choice. </li></ul><ul><li>Inkjets use quick-drying, water-based inks and a print head with a series of small nozzles that spray ink on the surface of the paper. </li></ul><ul><li>The print head assembly is driven by a belt-fed motor that moves the print head across the paper. </li></ul>
  23. 31. LASER PRINTERS <ul><li>Laser printers are known for their high volume output and low cost-per-page. </li></ul><ul><li>Laser printers share much of the same (or similar) technologies as photocopiers. </li></ul><ul><li>Mechanized rollers and gears pull a sheet of paper from a paper tray and through a charge roller, which infuses the paper with an electrostatic charge. The paper then passes through a printing drum, which is itself inversely charged and scanned by a laser that emits the print contents across the drum, discharging the drum at points corresponding to text and image points. </li></ul>
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