Input and output devices

3. • Input device captures information and translates it into a form
that can be processed and used by other parts of your computer.
Keyboards
Pointing devices
Game controllers
Scanners
Styluses
Microphones
Digital cameras
Web cams

5. The keyboard is the most common input
device. Types of keyboards include:
• Wireless
• Multimedia and one-touch access
• Portable keyboards for PDAs

7. Pointing devices are mainly used to choose and enter
commands
Pointing devices tend to have PS/2 connectors or
USB connectors
• PS/2 connector fits into a PS/2 port, which a small round
socket with small holes that fit the pins on the connector
• USB connectors fit into USB ports, and these are small
rectangular openings on the back or front of your computer,
or even on your keyboard or monitor

8.  Various pointing devices are available
 Types of pointing devices:
• Mouse
Mechanical mouse
Optical mouse
Wireless mouse
• Trackball
• Touchpad
• Pointing stick

9. Game controllers are used mainly to play games
Types of gaming devices
• Gamepads
• Joysticks
• Gaming wheels
• Force feed

10. Other types of input devices include:
• Scanners
• Styluses
• Microphones
• Digital cameras
• Web cams

11. •Scanner is a light sensitive device that helps you
copy or capture images, photos, and artwork
that exist on paper. Types of scanners include:
Flatbed

12. • 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

13. • Microphones are used to input
audio
• Three main types of
microphones are:
Desktop microphones
Headsets
Directional microphones
• Speech recognition is
increasingly being included in
application software

15. Output devices take information
within your computer and present
it to you in a form that you can
understand
Main output devices:
Monitors
Printers
Speakers

17. Devices with flat-panel displays
• Tablet PCs
• PDAs
• Cellular phones
• Desktop computers

18. CRTs
Flat-panel displays
Gas plasma
LCD (liquid crystal display)
Passive matrix
Active matrix
Called TFT (thin film transistor)
Separate transistor for every pixel

19. Screen size measured as a diagonal line across the
screen – from corner to opposite corner
Resolution the number of pixels displayed on the
screen (the higher the resolution, the closer together
the dots)
Pixels (or picture element) dots that make up the
image on your screen
Dot pitch is the distance between the centers of a
pair of like-colored pixels
Refresh rate the speed with which a monitor redraws
the image of the screen, and is measured in hertz

20. Inkjet – most popular
Makes images by forcing droplets through
nozzles
Top speed is 20 pages per minute
Laser
Forms images using an electrostatic
process
Prints between 3 and 30 pages per minute

21. Resolution of a printer is the number of
dots per inch (dpi) it produces.
Higher the resolution, better the image,
and usually the more costly the printer

22. Multifunction printer:
• Scan, copy, fax, and print
• Can be either inkjet or laser
• Cost less than buying individual
units
• Take up less desk space

23. A speaker is a device that
produces computer output as
sound
Speakers are common devices
in computer systems
Examples include:
• Built-in speaker
• Two-device set speakers
• Surround sound speakers