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Unit 5: Computer Hardware

tiny dots, called pixels, that are arranged in a rectangular form. The sharpness of the image (screen
resolution) depends upon the number of the pixels. Notes
Types of Monitors. There are different kinds of monitors depending upon the number of pixels.
Depending upon the resolution, monitors can be classified as follows:
1. CGA (Color Graphics Adapter)
2. MDA (Monochrome Display Adapter)
3. HGA (Hercules Graphics Adapter)
4. EGA (Enhanced Graphics Adapter)
5. VGA (Video Graphics Adapter)
6. SVGA (Super VGA)
The differences between these monitors are outlined in Table 5.1. Depending upon colour of display,
monitors can be classified as Monochrome (with single color black/white display) and Color (with
all colours display) Monitors. The pictures of two different models of color monitors are shown in
Figure 5.17.

Table 5.1: Comparison Among Different Types of Monitors
Type of Monitor Display Type Text Resolution Graphics Resolution
(Pixels)
CGA Text & Graphics Fair quality 320 × 200
MDA Text only Good quality —
HGA Text & Mono Graphics Fair quality 320 × 200
EGA Text & Enhanced Good quality 640 × 350
Graphics
VGA Text & Video Graphics Much better than 640 × 480
all the above
SVGA Text & Video Graphics Best quality 1600 × 1280

Figure 5.17 Two Models of Color Monitors

15" Multimedia Color Monitor 20" Color Monitor

Printer
Printer is the basic output device, which is used to print information on papers. Printers are essential
for getting output of any computer-based application. There are many types of printers, which are
classified on various criteria as illustrated in Figure 5.18. Printers are broadly categorised into two
types—Impact and Non-impact printers. Let us discuss these in detail.

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