MONITORS
The monitor is the computer's primary output device--its tool for displaying information, soliciting information, and responding to your's requests. It's also likely to be the center of your attention for most of the time you are using the computer. As a result, it is hard to underestimate the importance of a good monitor, meaning one that's clear, easy to read, and free of glare and flicker. A good monitor can make staring at the screen for eight hours bearable. A bad one can cause headaches, fatigue, and eye strain.
TYPES OF MONITORS
Desktop Computer monitors today exist in three main types : Gray scale, Color and LCD screens.
Gray scale monitors
are monitors capable of displaying various shades of gray as well as black
and white, while color and LCD monitors can display color in a range of colors.
Both color and Gray Scale Monitors come in two many separate types, in which
they differ in refresh rate, amount of colors, screen protection and such,
and work by using a Cathode ray tube (CRT), which, by the way, is the same
machine that is used in a normal TV. CRTs work by firing many electronic dots
of light from the back of the monitor to the screen. When the electrons hit
phosphors on the inside of the screen, the phosphors glow, creating patterns
of dots on your screen, and create the image.
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Up next in the line of monitor types is the LCD (Liquid Crystal Display). LCD screens work by using Liquid crystals (a fluid that reflects light) that are sandwiched between two polarized pieces of glass or plastic. These polarized sheets shut out all light waves except for those that are parallel to their particular plane. Inside the display, tiny electrodes pass current through the crystals, causing them to form spirals that bend the light to a greater or lesser degrees. The amount of current determines the amount of spiraling. This in turn determines how much of the light actually makes it through the front of the screen. The light is then passed through a color filer to give its color. LCD screens are often characterized as either passive or active matrix displays. In passive matrix displays, groups of pixels (screen dots) share the same electrodes. In active matrix displays, which are considerably more expensive, each pixel gets a transistor of its own. The resulting images are much clearer and easier to read. |
Of course, LCD
screens cost the most, followed by color and then the soon to be obsolete
grayscale monitor.
Notebook screens differ from desktops, as they need
to be small and sleek. A common screen used in notebooks is the LCD screen
mentioned earlier. Another screen type used for notebooks is the Gas Plasma
display. Gas plasma screens consists of tiny neon-like bulbs, which glow orange.
On the positive side, gas plasma displays have a much faster refresh rate
than LCD screen, which also leads to clearer images. On the negative side,
there's the orange colour which most people find unattractive, and the fact
that they're quite abit heavier than LCD displays.
The monitor
itself is only one of the pieces of equipment involved in displaying images
on your screen. The other is something known as a video adapter, a set of
circuitry that translates instructions from your computer into a form your
monitor can use.
In most personal computers,
the video adapter is an expansion board that fits into a slot on the computer's
motherboard. On some Macintosh computers, however, video circuitry is built
into the motherboard itself. Some PCs may even come with a hardware graphics
accelerator.
VIDEO STANDARDS
AND SCREEN RESOLUTIONS
Some monitors and video adapters
are capable of displaying images at various resolutions by using different
numbers of dots per inch. When you use a lower resolution, the image expands:
you see less on the screen but everything you do see is larger, as if you
were looking through a magnifying glass. When you use a higher resolution,
everything on the screen shrinks, allowing you to see more information at
once. Using a higher resolution may therefore make it possible for you to
compose your annual report in one window while viewing a spreadsheet with
this year's income statement in another window, for example, or to view a
dozen more columns and/or rows of spreadsheet data at one time. The only reason
to switch to a lower than normal resolution is if you have trouble seeing
and want to display larger characters or images on the screen. Resolution
depends on two things: your monitor, and your video adaptre. It also sets
the upper limit of the screen resolution---that is, how many dots per inch
you can display on screen. Some monitors are designed to display images at
only one resolution. Other common ones, known as multisync monitors, can display
images at various resolutions. Resolution is described in terms of number
of pixels. A pixel, which is short for picture element, means a dot used to
construct screen images. Resolution is usually described in terms of the number
of pixels displayed horizontally by the number of pixels displayed vertically
across the entire screen. The most common resolution in graphics mode us 1024
by 768 (1024 pixels horizontally and 768 pixels vertically).
Refresh rate is the speed of which
your monitor generates images. The higher the refresh rate, the less the jerkiness
and flickering. Higher refresh rates are also known to cause less headaches.
Refresh rates, too, depend on the quality of your video card and monitor.
Refresh rate is measured in hertz(hz). The most common refresh rates of today
range from 60 hz to 80 hz.
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In order to achieve higher standards of resolution and refresh rate, it may be needed to get a video accelerator. A video accerator is a seperate component card from the video adapter. Popular video accelerator cards of today are those such as the GEFORCE and Voodoo3, wich do not only inprove resolution and refresh rate but also add special effects and are about to show 3-dimensional graphics better - thus making the machine suited for games and multimedia. |
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