George FavourVISUAL DISPLAY UNIT (MONITOR)
The monitor is an output device that displays visual information generated by a computer.
It serves as the primary interface between the user and the computer system, presenting graphical and textual data in a human-readable form.
Types of monitors:
There are two primary types of computer monitors:
- Cathode Ray Tube (CRT) monitor
- Liquid Crystal Display (LCD) monitor
A Cathode Ray Tube monitor:
It is cheaper, more durable and able to withstand being damaged and remain functional, have superior response time has a superior contrast and there is no discernible flicker if the refresh rate is set to a sufficiently high value.
An LCD monitor:
It is lighter and more compact, requires less electricity to power, and tends to have better resolution and be built in considerably larger sizes. Liquid Crystal Display have been displacing CRTs for the last several years as prices fell.
LCD technology does not flicker, so it causes less eyestrain. LCDs screens are used in portable computer such as laptops, notebook and palmtop sized PCs.
Thin-Film-transistor (TLT-LCD) monitor is a variant of LCD monitor that used thin-film-transistor technology to improve on the existing LCD technology making a more brilliant display. This monitor is in most of our modern portable computer and it is replacing the LCD.
All monitors rely in a video card, which is located on the motherboard to display the information. It is the video card, which processes the data into images, which is eventually displayed on the monitor.
One of the major differences between LCD and CRT is that LCD is flat and CRT is massive and heavy.
The earlier Visual Display Units were able to show only two colors (monochrome) but nowadays, Visual Display Unit are capable of showing millions of colors.
Monochrome Monitors-
A monochrome monitor has two colors, one for foreground and the other for background. The colors can be white, amber or green on a dark (black) background. The monochrome monitors display both text and graphics modes.
Color Monitors-
A color monitor is a display peripheral that displays more than two colors. Color monitors have been developed through the following paths:
- CGA: This stands for Color Graphics Adapter. It is a circuit board introduced by IBM and the first graphics standard for the IBM PC. With a CGA monitor, it is harder to read than with a monochrome monitor, because the CGA (320 X 200) has much fewer pixels than the monochrome monitor (640 X 350). It supports 4 colors.
- EGA: It stands for Enhanced Graphics Adapter. It is a video display standard that has a resolution of 640 by 350 pixels and supports 16 colors. It supports previous display modes and requires a new monitor.
- VGA: VGA stands for Video Graphics Array. This is a video display standard that provides medium to high resolution. In a text mode, the resolution of this board is 720 by 400 pixels. It supports 16 colors with a higher resolution of 640 by 480 pixels and 256 colors with 320 X 200 pixels.
- Super VGA: This is a very high resolution standard that displays up to 65,536 colors. Super VGA can support a 16.8 million colors at 800 by 600 pixels and 256 colors at 1024 by 768 pixels. A high-priced super VGA allows 1280 by 1024 pixels. Larger monitors (17″ or 21″ and larger) with a high resolution of 1600 by 1280 pixels are available. VESA (Video Electronics Standards Association) has set a standard for super VGA.
Click here to read about Characteristics of Computer monitors.
George Favour
