Chapter 2 - Peripheral devices
megapixel
1 million pixels
digital camera
a device that captures still or moving images by recording them on a chip-based image sensor
photosites
a grid of tiny light-sensitive diodes
dot pitch (pixel pitch)
a measure of image clarity
Luminance
a measure of screen brightness usually expressed in candelas per square meter (cd/m2) with higher numbers indicating a brighter display
stylus
a pen shaped object with a tapered end that can be used for precise input and manipulation of small objects on screen
touch/trackpad
a touch-sensitive surface which you can tap and slide your fingers to manipulate the pointer, menus and other objects on the screen
integrated graphics
a type of graphics circuitry that's built into a computer's motherboard and uses system RAM for graphics processing
speech recognition
allows you to dictate commands and data using a microphone
pointing device
allows you to manipulate an on-screen pointer and other screen-based graphical controls
Esc (escape key)
an all purpose "go back" or undo key that hides menus and gets you out of various task modes
expansion bus
an electronic pathway that moves information between the microprocessor and RAM, and stretches to various ports and slots where data can be transferred to other electronic circuitry devices
CCD (charge coupled device)
an object onto a small image sensor that the lens in digital cameras focuses light from
peripheral device
any input, output, or storage equipment that might be added to a computer system to increase its functionality
keypad
arrow keys that move the screen-based insertion point
numeric keypad
calculator-styled keys
windows key
calls up the start screen used to select software applications and files
speech synthesizer
converts digital text into audio output
DLP (digital light processing)
creates an image by bouncing light off of microscopically small mirrors arranged on a semiconductor chip
duty cycle
determines how many pages a printer is able to churn out
keyboard
enters data and issues commands; the most important input device on desktop and laptops
graphics processing unit (GPU)
executes graphics commands, leaving the main processor free for other tasks
graphics tablet
features a pressure-sensitive surface and stylus for free-hand drawing
ink jet printer
has a nozzle-like print head that sprays ink onto paper to form characters and graphics
LCD (liquid crystal display)
produces on-screen images by manipulating light within a layer of liquid crystal cells
game controller
provides input to on-screen objects such as a pointer or character in a computer game
video memory
stores screen images as they are processed but before they are displayed
gestures
swipes, taps and other movements on a touchpad
duplex printing
the ability of a printer to print on both sides of the paper
response time
the length of time required for a pixel to change color to keep pace with the image being displayed on the screen
screen size
the measurement in inches from one corner of the screen diagonally across the opposite corner
color depth (bit depth)
the number of colors a device can display
screen resolution
the number of horizontal and vertical pixels that a device displays on a screen
aspect ratio
the relationship between the width and height of a displayed image
graphics card (graphics board/video card)
typically contains a graphics processing unit and special video memory
function keys
used for computer-specific tasks such as putting the computer into sleep mode, adjusting screen brightness, and using a second display screen
virtual keyboard
used to enter words and numbers on computers with touchscreens
mouse
used to move an on screen pointer, select various screen elements by clicking them, and move screen elements by dragging them
laser printer
uses the same technology as a photocopier to paint dots of light on a light sensitive drum
Ctrl (control key) and Atl (alternate key)
work in conjunction with other keys to invoke keyboard shortcuts
