Why would I need it?
Obviously, we all need monitors to see what we're doing on our computers. But why upgrade? Whether you're upgrading from an older monitor to a newer one, or picking out a monitor for a brand new system, a larger viewing space is always better. It's well worth spending a little extra for a larger and higher quality monitor, because your monitor is the link between you and your entire computer system. You look at it every day and often for extended periods of time. It affects the look of everything you do on your computer. It makes sense to get a monitor with the largest viewing area that your budget permits because your monitor is in it for the long haul. 

How do I go about buying one?
There are two basic kinds of computer monitors: CRT (cathode-ray tube) monitors and LCD (liquid crystal display) monitors. CRT is the technology used in television sets, and it is by far the most widely used technology for computer monitors as well. LCD technology, which is also called "TFT" or "flat-panel display," is seen most often in notebook computers, but it is also becoming more popular in desktop monitors. There are many differences between the two technologies, but we'll break them down into a handful of points for each one. 

CRT Monitors:

• Analog signal, compatible with most VGA graphics cards 
• Lower cost 
• Wider viewing angle 
• Better scaling to different screen resolutions 
• Excellent color quality, gamma quality, and contrast 

LCD Monitors:

• Digital or analog signal; graphics card with a digital port required for digital models 
• Thin and lightweight, fitting easily in any work environment 
• Less than half the power consumption of CRT monitors 
• Images do not flicker 
• Superior focus and screen brightness 

As LCD technology develops, it will more closely match the viewing angle, resolution, and low price of CRT technology, and the popularity of LCD monitors is expected to increase over time. 

The specifications that you should focus on when shopping for a CRT monitor are different from those you'll look for in an LCD monitor, so we'll cover the both types. 

For CRT monitors, pay attention to the following specs: flicker-free resolution, dot pitch, CRT type, and Viewable Image Size. 

Flicker-free Resolution:Resolution is a measurement of the number of pixels used to form an image on the computer screen. For example, a screen resolution of 1024 x 768 has 1024 pixels in each horizontal row and 768 pixels in each vertical column, for a total of 786,432 tiny pixels on the screen. The more pixels, the sharper the image. However, it takes a monitor longer to display the extra pixels in a higher resolution screen, so at higher resolutions the "refresh rate" of the screen image slows down. Maybe the monitor can redraw an 800 x 600 screen image 120 times every second, but at a higher resolution like 1280 x 1024 it can only redraw the image 60 times every second. At refresh rates below 75, the human eye notices the screen image flickering, and this causes eyestrain over extending viewing periods. For that reason, you normally won't use the highest screen resolution that a CRT monitor supports. Instead, you'll want to use a resolution that is high enough to give you sharp detail, but low enough that the monitor can redraw the screen quickly, so that no flickering is noticeable. The "flicker-free" resolution is the highest resolution with a refresh rate of 75 or above, which is fast enough to avoid tiring out your eyes. 

Dot Pitch:Dot pitch is the diagonal distance between two dots (phosphors) of the same color. The closer these dots are together, the sharper the picture can be, and the higher the screen resolution can be. Aperture grill pitch, or "slot pitch," is a similar measurement used by monitors which arrange phosphors into stripes instead of dots. A .25mm slot pitch is roughly equal to a .27mm dot pitch. For today's monitors, a .27mm or finer dot pitch (or a .25mm or smaller aperture grill pitch) is recommended, unless the monitor is a 14-inch or 15-inch model. Among smaller monitors, a .28mm dot pitch is still the most common standard. 

CRT Type:This describes the type of mask or grill used to define the dots or phosphors in the CRT screen. The various "shadow mask" types render a finer, more detailed image, since the light passes through precise holes in the mask. This makes them good choices for text-heavy applications and those involving fine lines, such as CAD/CAM applications. "Aperture-grille" models, on the other hand, allow more light through to the screen, resulting in sharper contrast, brighter images and richer colors. Such monitors have the edge for pre-press, desktop publishing and graphics-oriented applications involving color and images. The difference between the two types is small, but noticeable. Aperture grill CRT's boast the added advantage of a flat screen, which reduces reflections and distortions at the edges of the screen. However, by following a FST (Flat Square Tube) design, some shadow mask CRT's also offer a virtually flat screen. 

Viewable Image Size: This specification can be confusing. The nominal size of your monitor does not indicate precisely how much of the screen displays a picture. A 17-inch monitor, for example, does not give you 17 inches of viewable screen; it gives a little less, around 16 inches. Different models provide slightly different relative viewable image sizes. For instance, one 17-inch monitor may have a 16.1-inch viewable image area, while another may offer only 15.9 inches. Bigger is better, but other specifications are important, too. 

When shopping for an LCD monitor or LCD panel, you'll want to pay attention to specs such as the maximum screen resolution, the screen size, and the type of interface. 

Maximum Screen Resolution:The ideas behind "flicker-free" resolution do not apply to LCD monitors because LCD technology does not have to refresh a pixel for it to stay lit. This means that you can use the highest resolution available for the monitor without worrying about eyestrain due to screen flicker. Pick a monitor that offers a high screen resolution for the best sharpness and detail. 

Screen Size:This is the size of the LCD monitor's flat-panel screen, measured diagonally from one corner to the opposite corner. A 15-inch LCD screen provides almost as much viewable screen space that a 17-inch CRT monitor does. As with CRT monitors, the larger the screen size, the higher the resolution can be, and the more pleasant the image is to your eye. However, unlike a CRT monitor, an LCD monitor's screen size corresponds with its viewable image size. Therefore, a 15-inch LCD monitor provides a full 15-inches of viewable image size and not an inch less. 

Interface: The interface is simply the type of port that the monitor uses to connect to your computer. Unlike CRT monitors, almost all of which use a standard VGA port; LCD monitors may use a VGA port, a digital port, or USB port. Check the specifications of the LCD monitor carefully to see whether it requires a special graphics card that has a digital port for LCD monitors. Some digital LCD models include the necessary graphics card; some don't. If the monitor uses a USB connection, make sure that your computer is equipped with a USB port and is running Windows 98 or another USB-capable operating system. 

What products are most recommended?
Economy:For basic word processing, email, and secondary home computers, a low end 15" to17" monitor can be sufficient. 

Value: For only a little more money, you can buy a good 19".  With a bigger screen, you can do more with the Internet, multiple windows, and graphics, and eyestrain will be less of a problem. 

Performance: For high-end graphics, desktop publishing, CAD/CAM use, and Web design, you need the larger screen and higher resolutions of a 19" or 21" monitor. Gaming and Internet surfing also improves.