Wednesday, October 12, 2011
MONITORS - The display unit
After all the technical know how of CPU, I move along to one of the most important part of a Computer that is, the display unit - MONITOR. Often referred to as a display screen, a video display terminal (VDT) or visual display unit (VDU), monitor is the component of your computer system that displays the messages and data being processes and utilized by CPU.
There are two types of monitors available in the market. CRT and LCD monitors.
Lets look at them in detail and decide which one would be a better choice for your computing needs.
CRT Monitors: Short for Cathode-ray tubes, these were the only choice consumers had for monitors for many years. CRT has been in use for more than 100 years and is found in most televisions and computer monitors. A CRT works by moving an electron beam back and forth across teh back of screen, each time the beam makes a pass across the screen, it lights up phosphor dots on inside of glass tube, thereby illuminating the active portions of the screen. By drawing many such lines all over the screen it creates an entire screen of images.
LCD Monitors: Short for Liquid Crystal Display, LCD can be found in digital watches and computer monitors. These have sheets of polarizing material with a liquid crystal solution between them. An electric current pass through the liquid causes the crystals to align so that light cannot pass through them. Each crystal is like Shutter, either allowing or blocking light. Color LCD uses two basic techniques for producing color: Passive Matrix - a less expensive technology of two and Thin Film Transistor or Active Matrix that produces color images that are as sharp as CRTs but are expensive.
Let us compare CRT and LCD with respect to the necessary features of a monitor.
Resolution and Viewing Quality: Resolution on CRT is flexible and supports resolution up to 1600 X 1200 and higher, while on LCD it is fixed. The resolution of LCD can be changed but if you change it to other than native resolution you will notice a drop in image quality.
Both type of monitors provide bright and vibrant color display, however LCDs cannot display the maximum color range that a CRT can. In term of image sharpness, when running at native resolution, LCD's picture quality is very sharp while on CRT ,it can be blemished by soft edges or a flawed focus.
A CRT monitor can be viewed from any angle while LCD have a bit of problem. With different angles and distance your view changes in LCD and you may notice picture fade and possibly look as if it will disappear from view. Though recent LCD's provide viewing angle of 179 degrees which is at par with CRTs.
Refresh Rate: This an important feature to look for. CRT call this their Refresh Rate while LCD have this what is called Response time. This simply means the screen will refresh at a given interval. For instance CRT monitor's refresh rate is ~ 75 MHz while a LCD have a response time of 20 to 8 milliseconds. Again faster the refresh rate, better it will be for your eyes.
Gamers and people who watch a lot of movies on LCD screens would be better opting for something with a fast response time, around 8 ms as this reduces the ghosting effect of fast motion.
Brightness: Because LCDs require their own back light to create colour, brightness is an important factor. It's measured in candelas per metre squared or cd/m2, where one candle produces a brightness of 1 candela. The higher this number, the brighter the screen.
Contrast Ratio: This is the degree of difference between the extremes of light and dark colors. The higher the contrast ratio, the more detailed the image will be. Blacks will be blacker, whites will be whiter, and particularly text on the image will be more vivid. It will usually be written as 2000:1 or 1000:1
Screen (Viewable) Size: Most people tend to look at a 17 inch CRT or bigger. When you purchase a 17 inch CRT you usually get 16 inches or a bit more actual viewing area. This is due to bulky frame of CRT. If you purchase a 17 inch LCD monitor you get actual viewing area which is 17 inch or a little less.
Physical Size: There is no denying that LCD wins in terms of physical size and the space it needs. CRT are big, bulky and heavy.
Physical Size of LCD and CRT
Video Card compatibility: It goes without saying that when you are looking at new monitors you should also look at your video card. Make sure that your video card can support the recommended refresh rate and resolution of your monitor. This will help extend the life of both your monitor and your eyes.
Warranty: The manufacturer's warranty is also something to consider when purchasing a new monitor. CRT monitors have a tendency to fail after 3 years and LCD monitors are usually rated from 10 to 50 thousand hours of operation. The longer the warranty the better chance you will have at getting it replaced if and when it does fail.
Price: As an individual one time purchase LCD will be a bit more expensive but throughout lifetime they are cheaper has they have longer lifespan and lower power consumption. The cost of both technologies have come down over the past few years and expect even more sliding. You may pay more for LCD but considering the actual size you get, the money to size advantage is still with LCD.
To sum it up, Here are PROS and CONS of CRT and LCD
PROS: Great value for money, Mature technology, Good for graphical detail, Can accommodate many different resolutions.
CONS: Big, Take up a lot of space, Cost more to run than an LCD
PROS: Less desk space needed, Require less power to run, more environmentally friendly, Increased Viewable area, Faster response time aids in image sharpness.
I hope this information was useful to you and will help you deciding which monitor to buy. In my opinion LCD are preferable over CRT. Though it varies from user to user.
Please feel free to comment on anything to everything. Your valuable advice will help me improve better.