Graphics Displays (CRT and LCD) &

Display Adapters(Video Cards)

Components of VDU(Visual Display Unit )

Cathode-Ray Tubes(CRT)

CRT(Color)

CRT Explained 1. Three Electron guns (for red, green, and blue

phosphor dots) 2. Electron beams 3. Focusing coils 4. Deflection coils 5. Anode connection 6. Mask for separating beams for red, green, and blue part of displayed image 7. Phosphor layer with red, green, and blue zones 8. Close-up of the phosphor-coated inner side of the

screen

Shadow Masking in Color CRT

Liquid Crystal Displays(LCD)

LCD

Video Display Adapter(Video Card)Continue…A video card is a special printed circuit

board that plugs into motherboard.A video card is responsible for

displaying graphics on monitor.Display adapter consists: * VDU memory.

* Circuitry which transfers the contents of VDU memory on the screen.

Display AdaptersDisplay Adapters refreshes the screen

50 to 70 times a second so that image persists on the screen.

Low refresh rates causes the screen to flicker or snowing effect.

Types of Display Adapters

Monochrome Adapter(MA)

Color Graphics Adapter(CGA)

Enhanced Graphics Adapter(EGA)

Multicolor Graphics Adapter(MCGA)

Video Graphics Adapter(VGA)