Sim-Ex™ Tutorial for A+ Essentials

2.0 Laptop and Portable Devices

2.1 Identify the fundamental principles of using laptops and portable devices

LCD technologies (e.g. active and passive matrix, resolution such as XGA, SXGA+, UXGA, WUXGA, contrast ratio, native resolution)

LCD (short for Liquid Crystal Display) is the technology used for displays in notebook and other smaller computers. LCDs consume much less power than conventional CRT (Cathode Ray Tube) displays, and at the same time much thinner, making it ideal for use in portable devices.

There are two types commonly used in LCD displays. These are

Passive Matrix Displays, and
Active Matrix Displays.

The active matrix LCD is also known as a Thin Film Transistor (TFT) display.

The passive matrix LCD consists of a grid of conductors with pixels located evenly at each intersection in the grid. Current is sent across two conductors on the grid to control the light emitted through a given pixel element.

An active matrix has a transistor located at each pixel intersection, and the switching times are very fast. For this reason, the active matrix display provides better interactivity, and smooth scrolling of text/images. Active matrix technology is superior to passive matrix, and TFT is used widely for notebook computers for this reason.

Laptop Displays: Different display resolutions widely used in notebook or portable computers is as given below:

Standard 4:3 Aspect Ratio

SVGA (Super Video Graphics Array): 800 x 600
XGA (Extended Graphics Array): 1024 x 768
SXGA (Super Extended Graphics Array): 1280 x 1024
SXGA+ (Super Extended Graphics Array+): 1400 x 1050
UXGA (Ultra Extended Graphics Array): 1600 x 1200
WUXGA (Wide Ultra Extended Graphics Array) 1920 x 1200

Resolutions higher than 1024 x 768 are used for display sizes of 14 inches or above.

WUXGA 1920X1200 is best suited for HDTV. This is a wide screen display with aspect ratio of 16:9.

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