Section 3.1. Monitor Basics


3.1. Monitor Basics

Monitors, those screens you stare at all day, come in two basic types: the old-school, TV-shaped Cathode Ray Tube (CRT) monitors from yesteryear, and the newer , flat, and thin Liquid Crystal Display (LCD) monitors filling the store shelves today.

When dealing with either breed of monitor, the same confusing terms pop up on sales floors and Windows menus . These terms top the list:

  • Screen size . Borrowing some trickery from TV-land, the computer industry measures monitors diagonally to create the illusion of executive- sized desktops. However, a 17-inch monitor gives you only a 13.6-inch-wide Windows desktop. Even an expensive 21-inch monitor offers only about 16 inches of workspace.

  • Pixels . Like the Sunday funnies, a monitor displays pictures by using tiny colored dots. The industry refers to the dots as pixels . A monitor displays text by simply stacking dots in different configurations, shown in Figure 3-1.

  • Resolution . Resolution refers to the number of pixels your monitor can use when filling up the screen. For instance, a low resolution setting like 640 x 480 turns the screen into a grid of 640 lines of 480 pixels. A higher resolution of 1024 x 768 creates a grid of 1024 rows of 768 pixels. A higher resolution produces a larger grid, which means a larger desktopsomething everybody appreciates when trying to place two large windows next to each other.

  • Refresh rate . CRT monitors work much like movie projectors, constantly flashing new frames onto the screen. Even when you're viewing a static imagea Web page, for instanceyour monitor constantly refreshes the screen. If the monitor's not speedy enough, the screen flickers noticeably, like you're watching an old movie. Measured in hertz, the refresh rate refers to the speed with which the monitor updates the screen. CRT monitors work best at the highest refresh rate they offer, usually from 75100 Hz. LCD monitors display images differently than CRT monitors, so they don't have flicker problems. Keep their refresh rate set at 60 Hz. (See Section 3.8.2 for instructions on how to adjust the refresh rate.)

  • Contrast ratio . Found on a monitor's list of technical specifications, contrast ratio measures the ratio of the brightest color to the darkest color that a monitor can display. Higher numbers are best, as they let a monitor display very dark blacks along with very bright whites and colors. CRT monitors average a 700:1 contrast ratio; most LCD monitors now match or exceed that.

  • Response time . This rating, measured in milliseconds (ms), refers to the time required for an LCD monitor's pixels to turn from black to white, and then return to black. Lower numbers mean faster response times. A lower response time lets a character dash across the screen without leaving a trail of ghostly images following it.

  • Viewing angle . Another term applied only to LCD monitors. The viewing angle measures how wide an arc viewers can be positioned within and still see everything that's on a display. A wide viewing angle lets lots of people see the monitor, even if they're standing off to the side. A narrow viewing angle restricts the view to yourself, and perhaps the guy peering over your shoulder.

Figure 3-1. Everything displayed on your screen consists of pixelslittle dots like the ones shown here. Your computer turns pixels on or off in different colors to display text or images. To give your monitor more (or fewer) dots to play with, adjust its resolution. A resolution of 640 x 480, for instance, gives your monitor a grid that's 640 pixels wide and 480 pixels high. Switching your monitor to a higher resolution, like 1280 x 1024, gives it a larger grid, meaning you can pack even more information into the screen. The tradeoff ? The monitor shrinks everything to fit the screen.

3.1.1. LCD (Liquid Crystal Display)

Today, nearly everybody buys an LCD monitor (also called a digital monitor); these are the sleek, flat-screen models like the one shown in Figure 3-2. As is the case with most technological innovations, problems plagued early LCD monitors. The screens faded when viewed from the sides, for instancegreat for privacy when working on an airplane's seat tray, but not so good for presentations. Also, early LCD screens didn't update their displays quickly enough to satisfy hardcore gamers: fast-moving characters left unwanted "ghosts." Manufacturers earned their chops building LCD monitors for laptops, so they fine- tuned desktop LCD displays fairly quickly. Today, LCD monitors surpass CRT monitors in nearly every way: they provide clearer screens, consume less desk space, require much less energy, give off less heat, are easier on the eyes, and, well, they just plain look nicer.

Just like their predecessors, most LCD monitors connect to a PC's VGA port (Figure 1-13, top). The best LCD monitors come with a DVI (Digital Visual Interface) port (Figure 1-13, bottom)a newer port specifically designed to let these new digital monitors display their clearest images.

Figure 3-2. Top: With their sleek look, small footprint, and vivid displays, LCD monitors like this one have pretty much pushed CRT monitors out of the marketplace .
Bottom: Like many new LCD monitors, this one comes with two ports, letting it connect to a wider range of PCs. The monitor's DVI port (left) lets the monitor plug into the digital cards found on newer PCs and video cards. Next to it, an old-style VGA port (right) lets the monitor plug into the VGA ports found on nearly every PC, especially older ones.

To make things simple, some LCD monitors come with both a VGA and a DVI port, shown in Figure 3-2, bottom, so you can plug them into PCs bearing either one of those openings.


Tip: When shopping for an LCD monitor with a DVI port, give bonus points to ones that come with their own digital cable. Those cables aren't cheap; they cost anywhere from $15 to $50, depending on their quality and manufacturer.

Today, the biggest problem with LCD monitors comes from dead pixels pixels that don't light up correctly. Some dead pixels constantly display an annoying pinpoint of one color; others stay black. Dead pixels aren't very noticeable when you view digital photos; after all, one dead pixel blends in easily among 786,432 working ones. But when viewed on a background of one colora completely blue or white desktop, for instancedead pixels stand out like a pinhole in the window blinds shading an afternoon sleeper.

Manufacturers don't want to scrap an entire monitor because of one or two dead pixels, so they ship the monitors to stores anyway. Some people never notice the dead pixels or don't rank them high on their worry list. Others find the dead pixels bothersome, and want their monitors replaced .

Since dead pixels don't irritate everybody, manufacturers rarely publicize their replacement policies. Some limit replacements to monitors with a certain number of dead pixelsthree or more, for instance. Others hinge their replacement on the dead pixel's locationdead pixels near the corners or edges don't garner as much sympathy as those living near the center. Others replace monitors only for customers who protest loudly and make several phone calls. Before buying a monitor, ask the salesperson or vendor about the store's replacement policy.

FREQUENTLY ASKED QUESTION
The Analog-to-Digital Dilemma

The back of my flat-panel digital monitor has two portsVGA and digital. Since it's a digital monitor, why does it need a VGA port, which is analog? Should I use the VGA or digital port?

Since you already bought the monitor, use the port that fits the one on your video card. Your monitor works with either of them. But to understand which port truly works the best, you need to understand the difference between analog and digital .

When computers want to display something onscreen, they communicate with the monitor using their native, numerical language digital ones and zeroes. CRT monitors, however, don't work with numbers. Their technology depends on subtle changes in electric currenti.e., analog information.

To bridge that analog/digital communication barrier , a PC's VGA circuitry converts the digital information into analog information before sending it the monitor. That solution works great for CRT monitors. But the arrival of digital monitors meant computers could finally start sending their numbers directly to the monitor. VGA cards and ports were suddenly obsoletealmost.

Digital monitors were too expensive when first introduced, and they required expensive new digital video cards. Few people could afford both the monitor and the card, so manufacturers built VGA ports into many digital monitors, letting them work with the millions of VGA cards already living on computers worldwide. Then, they placed an Analog-to-Digital Converter (ADC) inside the digital monitor. That's right: your PC creates digital information, which the VGA card converts to analog before sending to the monitor. Then the digital monitor converts the analog information back to digital for displaying onscreen.

And that's why digital monitors don't look their best when plugged into a VGA port: Some of the quality disappears during the two translations. Many people don't notice the difference, since the converters work very well these days. But to use your digital monitor to its fullest capacity, plug it into a video card with a digital port.


3.1.2. CRT (Cathode Ray Tube) Monitors

CRT monitors are bulky and heavy, and they resemble TV sets (Figure 3-3), but they do bear one redeeming quality: they're relatively cheap, usually costing less than $150if you can still find any for sale.

Gamers and graphic artists held on firmly to CRT monitors, as they preferred CRT monitors' fast screens and vivid colors. But when LCD monitors finally caught up, those two camps packed up and moved along the technological trail toward LCD displays.

Figure 3-3. A computing mainstay for many years , CRT monitors no longer fill the shelves of computer stores. These bulky and heavy monitors lost popularity when higher-quality LCD monitors came down in price.

As CRT monitors slide toward the computer graveyard, they aren't finding a welcome funeral. The monitors contain toxins like cadmium, mercury , and large amounts of leadenough to define them as hazardous waste in California, Florida, Maine, Massachusetts, and Minnesota, with other states passing similar restrictions to keep them out of their landfills.

On the plus side, CRT monitors have been around so long that nearly every PC recognizes them on contact. Plug nearly any CRT monitor into your PC's VGA port (Section 1.8.1), and Windows jumps onto the screen.




PCs
PCs: The Missing Manual
ISBN: 0596100930
EAN: 2147483647
Year: 2005
Pages: 206
Authors: Andy Rathbone

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