Television and Radio |

For the past 75 years, the vast majority of televisions have been built around the same technology: the cathode ray tube (CRT). In a CRT television, a gun fires a beam of electrons (negatively-charged particles) inside a large glass tube. The electrons excite phosphor atoms along the wide end of the tube (the screen), which causes the phosphor atoms to light up. The television image is produced by lighting up different areas of the phosphor coating with different colors at different intensities

Cathode ray tubes produce crisp, vibrant images, but they do have a serious drawback: They are bulky. In order to increase the screen width in a CRT set, you also have to increase the length of the tube (to give the scanning electron gun room to reach all parts of the screen). Consequently, any big-screen CRT television is going to weigh a ton and take up a sizable chunk of a room.

A new alternative has popped up on store shelves: the plasma flat panel display. These televisions have wide screens, comparable to the largest CRT sets, but they are only about 6 inches (15 cm) thick. In this article, we’ll see how these sets do so much in such a small space.

If you’ve read How Television Works, then you understand the basic idea of a standard television or monitor. Based on the information in a video signal, the television lights up thousands of tiny dots (called pixels) with a high-energy beam of electrons. In most systems, there are three pixel colors — red, green and blue — which are evenly distributed on the screen. By combining these colors in different proportions, the television can produce the entire color spectrum.

The basic idea of a plasma display is to illuminate tiny, colored fluorescent lights to form an image. Each pixel is made up of three fluorescent lights — a red light, a green light and a blue light. Just like a CRT television, the plasma display varies the intensities of the different lights to produce a full range of colors.

Home audio and video systems have changed dramatically from their earliest incarnations. Television began as a mechanical device but didn’t really catch on until electronic TVs began to hit the market and more broadcasters began signing on.

It grew more popular as it changed from tiny black-and-white screens to large color sets. And now you can buy TVs that can take up the whole wall of your living room! In February 2009, television stations in the United States will switch from analog to digital signals, encouraging people to buy converter boxes or make the move and upgrade, which means plunking down big money for new high-definition sets.

Televison may be the cornerstone of home audio and video setups, but most people need more than just a good TV. We started recording TV shows on videocassette recorders, but fewer people use them anymore. They’re all switching to digital video recorders, DVDs and Blu-ray discs. And then there’s those sophisticated component sound systems and surround sound systems that add so much character and depth to our television and movie watching.

No doubt, home audio and video equipment is very popular, but deciding on the best equipment can be a challenge. Each person has his or her own preferences that lead to very different choices. We have a whole library of home audio and video articles that will help you learn more about different technologies. Find out what’s inside a remote control. Learn the differences between plasma and LCD televisions. See how speakers work. Find out how to bend your TV schedule to suit your viewing habits, with Internet TV, the TiVo and the Slingbox. We’ll even sneak a peek at the next wave of technologies, such as ultra-high definition TV. Explore our Home Audio and Video articles to find out more.