A plasma screen is made up of thousands of pixels containing gas that’s converted into “plasma” by an electrical charge. The plasma causes phosphors to glow red, green, or blue, as dictated by a video signal. The result: a colorful display with high brightness and a wider viewing angle than most rear-projection sets and LCD (liquid-crystal display) TVs. Thanks to steady improvements in plasma technology, the best of these sets have excellent or very good picture quality. Some picture-tube TVs still do slightly better with fine detail, color accuracy, and subtle gradations of black and gray, but plasma TVs are coming closer.

However, the picture isn’t all rosy. Like projection TVs using CRT (cathode-ray tube) technology, plasma sets are vulnerable to screen burn-in. Also, plasma sets run hotter and consume more power than any other type of TV. Because plasma sets are relatively new, their long-term reliability is still a question.

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When buying a plasma TV, you’ll face a choice between HD (high definition) and ED (enhanced definition) sets, which cost less. The two types differ in native resolution, meaning the fixed number of pixels on the screen. In a spec like 852x480, note the second number. If it’s 480, the set is ED; 720 or higher, it’s HD. Both types of sets should be capable of up- or down-converting signals to match their native resolution. ED sets can display the full detail of 480p signals such as those output by a progressive-scan DVD player. When connected to an HD tuner, many can down-convert HD signals (which are 720p or 1080i) to suit their lower-resolution screens. While you won’t see true HD, the picture quality can be very good. If you sit too close to an ED set, though, images may appear coarser than on an HDTV, as if you were looking through a screen door.

There’s another major choice. Within the HD category, there are three types of TV sets: HD-ready sets. Also called HDTV monitors, these sets can display standard-definition analog programs (which still account for most non-prime-time TV broadcasts) on their own. To display digital programs, they require a digital tuner to decode those broadcasts. If you’re getting your HD programming from cable or satellite, your digital cable box or satellite receiver has the appropriate digital decoder built in. All you have to do is connect your HD-ready TV to the box and you’re all set. Cable companies charge a small rental fee for digital or HD-capable boxes. To receive HD via satellite, you need an HD receiver and special dish antenna(e). Together, these cost about $300, but you may be able to get them from the satellite company at little or no charge as part of a promotion.

You can also get digital broadcasts, including HD, over the air, via an antenna. To do so, you’ll have to buy a digital tuner called an ATSC (Advanced Television Systems Committee) tuner—the external box costs a few hundred dollars. However, there’s no charge for service as there is with cable or satellite. Some satellite receivers also offer a built-in ATSC digital tuner. To receive digital programming via antenna, you must be fairly close to a transmitter, with an unobstructed view. With digital signals, you’ll either have a clear, strong signal or none at all.

Integrated HDTV sets. These have the ATSC digital tuner built in, which enables them to decode any digital signals, including HD with no additional equipment when used with a roof antenna. You may be able to receive the major networks’ HD offerings transmitted over the air in your area, but not the premium channels available on satellite and cable. To get HD via cable or satellite, integrated sets require an HD-capable cable box, CableCard, or satellite receiver—the built-in digital tuner only works for off-air digital broadcasts. As of July 2005, all new TVs 36 inches and larger--a category covering most plasma TVs—were required to have a built-in digital tuner to comply with a government ruling. Although integrated HDTVs have a digital tuner for off-air programs, most of these sets still require an HD-capable cable box or satellite receiver to get cable or satellite.

Digital-Cable-Ready (DCR) sets. Some new integrated models, called digital-cable-ready (DCR) or plug-and-play sets, can receive digital-cable programming without using a set-top box. For HD and premium cable programming--and possibly for any digital programming--you must insert a CableCard into a slot on the set. You usually have to pay a few dollars a month to rent the card from the cable company. Current DCR TVs are not interactive, so even with a CableCard in the slot they can’t provide features such as an interactive program guide, video on demand, or pay-per-view ordering via remote. Second-generation DCR TVs and CableCards should be here soon, and they’re expected to have two-way capability, allowing for interactive features. Integrated sets typically cost more than HD-ready sets, with digital-cable-ready models costing the most.

Among the brands in the plasma TV category are Hitachi, Panasonic, Philips, Pioneer, Samsung, Sharp, Sony, and Toshiba. Prices have dropped sharply over the past year or two. At publication time, HD-ready models with 40- to 44-inch screens, the best-selling size, were going for $3,000 to $5,000 or more. TVs with 50-inch or larger screens were selling for $4,500 and up. Look for prices to fall further, now that companies such as Dell and ViewSonic have expanded from the computer arena into TVs with aggressive pricing.