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Using Information Technology Chapter 5 Hardware--Input & Output.

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Presentation on theme: "Using Information Technology Chapter 5 Hardware--Input & Output."— Presentation transcript:

1 Using Information Technology Chapter 5 Hardware--Input & Output

2 Hardware--Input & Output Taking Charge of Computing & Communications 5.1Input & Output 5.2Input Hardware 5.3Output Hardware

3 5.1 Input & Output Input hardware - devices that translate data into a form the computer can process Output hardware - devices that translate information processed by the computer into a form that humans can understand

4 5.2 Input Hardware Keyboard - a device that converts letters, numbers, and other characters into electrical signals that can be read by the computers processor Traditional keyboards… Braille keyboard One-handed keyboard

5 Keyboards Specialty keyboards and terminals: Dumb terminal, VDT, display & keyboard, but no processing Intelligent terminal Internet terminal Dumb terminal

6 Keyboards Examples of intelligent terminals: Automatic teller machine (ATM) Point-of-sale (POS) terminal Specialty keyboards and terminals: Dumb terminal Intelligent terminal Has own memory & processor Internet terminal

7 Keyboards Specialty keyboards and terminals: Dumb terminal Intelligent terminal Internet terminal: –Web terminalWeb terminal –Network computer –Online game player –PC/TV –PDA PDA (Internet terminal)

8 Pointing Devices Pointing devices - control the position of the cursor or pointer on the screen Mouse Trackball Pointing stick Touchpad Mouse for right-handed user

9 Pointing Devices The mouse and its variants: –Mouse –Trackball –Pointing stick –Touchpad Ergonomic trackball Pointing stick Touch pad

10 Pointing Devices Touch screen - a video display screen that has been sensitized to receive input from the touch of a finger Touch screen

11 Pointing Devices Pen input: Pen-based computer system - allows users to enter handwriting and marks onto a computer screen by means of a penlike stylus rather than by typing on a keyboard Light pen - a light-sensitive penlike device connected by a wire to the computer terminal

12 Pointing Devices Pen input: Digitizer - converts drawings and photos to digital data using a mouselike device called a puckDigitizer Digitizing tablet - electronic plastic board on which each specific location corresponds to a location on the screen Digitizing tablet

13 Source Data-Entry Devices Scanning devices - imaging systems: Scanners - devices that use light-sensing equipment to translate images of text, drawings, photos, and the like into digital form

14 Source Data-Entry Devices Scanning devices – bar-code readers: Bar codes - vertical zebra- striped marks you see on most manufactured retail products Bar-code readers - optical scanners that translate the symbols in the bar code into digital code

15 Source Data-Entry Devices Scanning devices - mark- & character-recognition: MICR - Magnetic-ink character recognition. Reads the strange-looking numbers printed at the bottom of checksMICR OMR OCR

16 Source Data-Entry Devices Scanning devices - mark- & character-recognition: MICR OMR - Optical mark recognition. Uses a device that reads pencil marks and converts them into computer-usable formOMR OCR

17 Source Data-Entry Devices Scanning devices:mark- & character-recognition: MICR OMR OCR - Optical character recognition. Uses a device that reads preprinted characters in a particular font and converts them to digital code

18 Source Data-Entry Devices Scanning devices - fax machines… Types of fax machines: Dedicated fax machine Fax modem Dedicated fax machine Fax modem

19 Other Source Data-Entry Devices Audio-input devices Webcams and video- input cards Digital cameras Voice-recognition systems

20 Other Source Data-Entry Devices Audio-input devices Webcams and video-input cards Digital cameras Voice-recognition systems Human-biology input devices (biometrics)biometrics

21 5.3 Output Hardware Softcopy - data that is shown on a display screen or is in audio or voice form Hardcopy - printed output

22 Softcopy Output: Display Screens Display screens - output devices that show programming instructions and data as they are being input and information after it is processed

23 Softcopy Output: Display Screens Screen clarity… Pixel (picture element) - the smallest unit on the screen that can be turned on and off or made different shades

24 Softcopy Output: Display Screens Screen clarity… Dot pitch (dp) - the amount of space between the centers of adjacent pixels; the closer the dots, the crisper the image

25 Softcopy Output: Display Screens Screen clarity… Resolution - the image sharpness of a display screen; the more pixels there are per square inch, the finer the level of detail dpi = dots per inch Standard resolutions (horizontal x vertical) 640 x x x x x x 1440

26 Softcopy Output: Display Screens Screen clarity… Refresh rate - the number of times per second that the pixels are recharged so that their glow remains bright The higher the refresh rate, the more solid the image looks (less flicker).

27 Softcopy Output: Display Screens Two types of monitors: CRT - a vacuum tube used as a display screen in a computer or video display terminal Flat-panel display - made up of two plates of glass separated by a layer of a substance in which light is manipulated

28 Softcopy Output: Display Screens Active-matrix versus passive-matrix flat-panel displays: –Active-matrix - each pixel on the screen is controlled by its own transistor (brighter & sharper, but more expensive) –Passive-matrix - a transistor controls a whole row or column of pixels (provides sharper image for single color screens but more subdued for color)

29 Softcopy Output: Display Screens Color & resolution standards: SVGA – Super video graphics array (most common w/ 15 monitors) XGA – Extended graphics array (17-19 monitors) SXGA – Super extended graphics array (19-21 monitors) UXGA - Ultra extended graphics array (popular w/ design & graphic artists

30 Hardcopy Output: Printers Printer - an output device that prints characters, symbols, and perhaps graphics on paper or another hardcopy medium Dpi (dots per inch) - resolution measure for printers. Specifies the number of dots that are printed in a linear inch

31 Hardcopy Output: Printers Impact printer - forms characters or images by striking a mechanism such as a print hammer or wheel against an inked ribbon, leaving an image on paper (dot matrix printer)Impact printer Non-impact printer - forms characters and images without direct physical contact between the printing mechanism and paper –Laser printer - creates images on a drum which are treated with a magnetically charged toner, & then transferred from drum to paper –Ink-jet printers - spray small, electrically charged droplets of ink from four nozzles through holes in a matrix at high speed onto paper –Thermal printers - use colored waxes and heat to produce high quality images by burning dots onto special paper

32 Hardcopy Output: Printers Multifunction printer - output device that combines several capabilities, such as printing, scanning, copying, and faxing

33 Other Output Sound output - devices which produce digitized sounds, ranging from beeps and chirps to music Voice output - devices which convert digital data into speech-like sounds Video output - photographic images which are played at frames per second to give the appearance of full motion

34 Concept Check Which type of scanning technology reads the special characters printed at the bottom of checks? Magnetic-ink character recognition (MICR)

35 Concept Check What is the smallest unit on the screen that can be turned on and off or made different shades? Pixel (short for picture element)

36 Concept Check What is the measure specifying the number of times per second that screen pixels are recharged? Refresh rate

37 Concept Check How is screen resolution specified--vertical x horizontal, or horizontal x vertical? Horizontal x vertical

38 Concept Check What is the measure of resolution for printers? Dots per inch (dpi)

39 Concept Check What is the amount of space between the centers of adjacent pixels? Dot pitch (dp)

40 Concept Check What type of scanning technology is used to read pencil marks, such as those made by students on examination forms? OMR (Optical mark recognition)

41 Concept Check What is an example of an impact printer? Dot-matrix printer

42 Concept Check Which type of printer produces the very highest-quality color output? Thermal printer

43 Concept Check What type of input device consists of a small, flat surface over which you slide your finger, using the same movements as you would with a mouse? Touchpad

44 Concept Check What is the term for printed output? Hardcopy

45 Concept Check Does a very crisp image require a small dot pitch or a large dot pitch? A small dot pitch (the closer the dots, the crisper the image)


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