Display Specifications - CompTIA A+ 220-801: 1.10

Refresh rates

• Number of times per second the screen is redrawn

 

• Measured in hertz (Hz)
• CRT displays
• Electron beam "paints" every line of the screen
• Slower refresh rates tend to flicker
• Larger displays need to be set at 72 Hz or higher

• LCD displays
• No electron beams
• Refreshes the entire screen at 60 Hz
• Really a frame rate

Display resolution

• Number of pixels on a display
• Width x Height
• Actually pixel dimensions

• XGA
• 1024x768

• SXGA
• 1280x1024

• UXGA
• 1600x1200

Native resolution 

• An LCD display is fixed
• The number of pixels doesn't change
• A display looks best when the video settings match a display's native resolution
• A mismatch can cause distortion
• If changing the display resolution, try using a multiple of the native resolution
• 1600x1200 is the same ratio as 800x600

Display brightness

• Luminance
• Candela per square meter (cd/m2)
• More is better

• Lumens
• An ANSI test
• 3,000 lumens works in a dim room
• 6,000 lumens works in a sunlit room

• Contrast ratio
• Ratio between black and white
• A wider range is better

Analog vs digital 

• Analog video
• Transmitted as a continuous signal
• VGA video/ DE-15 interface
• Digital video
• Transmitted as discrete values
• DVI (Digital Visual Interface)
• HDMI (High-Definition Multimedia Interface)

Display Filters

• Privacy 
• Fade the screen to black or gold when viewed at an angle
• Placed on the front of a display
• Anti-glare
• Reflective screens are common
• Reduce glare
• Improve viewing
• Useful in bright light

 Multiple displays

• Connect more than one display
• Flexible work environment
• Extend a desktop
• Each display is independent 
• Location is determined in the OS

• Mirror a desktop
• Each display shows identical information
• Useful for presentations