Datasheet

54
Chapter 1
Hardware
Display resolutions include the following, which you must know for the A+
Essentials exam:
XGA Extended graphics array has been around since 1990. It’s a 1024
×768 resolution
that offers fixed-function hardware acceleration for 2D tasks.
SXGA+ Super extended graphics array is a 1400
×1050 resolution commonly used on 14-
or 15-inch laptops. Its typically considered the maximum resolution that video projectors
will work with.
UXGA Ultra extended graphics array is a 1600
×1200 resolution and is the next step in
the monitor-resolution evolution.
WUXGA Widescreen ultra extended graphics array is a resolution of 1920
×1200 with a
16:10 screen aspect ratio. It’s also a standard for use with television sets, at a slightly differ-
ent ratio.
Contrast ratio is a measurement of the brightness of the LCD panels. A general rule
of thumb is the greater the contrast ratio, the brighter the display can be, and thus a
rating of 3000:1 is preferred over 800:1. The native resolution of an LCD monitor is its
ideal resolution setting without needing to stretch the image (which causes the image
quality to degrade).
CRT Displays
In a CRT (cathode ray tube), a device called an electron gun shoots electrons toward the
back of the monitor screen (see Figure 1.20). The back of the screen is coated with special
chemicals (called phosphors) that glow when electrons strike them. This beam of electrons
scans the monitor from left to right and top to bottom to create the image.
FIGURE 1.20 How a CRT monitor works
Scan magnets
Electron gun
Electron beam
Monitor
case
Monitor
screen
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