• Input device captures information and translates it into a form that can be processed and used by other parts of your computer. KeyboardsPointing devicesGame controllersScannersStylusesMicrophonesDigital camerasWeb cams

The keyboard is the most common input device. Types of keyboards include:• Wireless

• Multimedia and one-touch access

• Portable keyboards for PDAs

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

Various pointing devices are available

Types of pointing devices:• Mouse

Mechanical mouse

Optical mouse

Wireless mouse

• Trackball

• Touchpad

• Pointing stick

Game controllers are used mainly to play games

Types of gaming devices• Gamepads

• Joysticks

• Gaming wheels

• Force feed

Other types of input devices include:

• Scanners

• Styluses

• Microphones

• Digital cameras

• Web cams

•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

• 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 PCsGraphics tablets

• Microphones are used to input audio

• Three main types of microphones are:

Desktop microphonesHeadsetsDirectional microphones

• Speech recognition is increasingly being included in application software

Output devices take information within your computer and present it to you in a form that you can understand

Main output devices:MonitorsPrintersSpeakers

Devices with flat-panel displays

• Tablet PCs

• PDAs

• Cellular phones

• Desktop computers

CRTsFlat-panel displays

Gas plasmaLCD (liquid crystal display)

Passive matrixActive matrix

Called TFT (thin film transistor)Separate transistor for every pixel

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

Inkjet – most popularMakes images by forcing droplets through

nozzlesTop speed is 20 pages per minute

Laser Forms images using an electrostatic

processPrints between 3 and 30 pages per minute

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

Multifunction printer:

• Scan, copy, fax, and print

• Can be either inkjet or laser

• Cost less than buying individual units

• Take up less desk space

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