Saturday, August 26, 2006

What is a Plasma TV?


Plasma TV is the high definition, commonly known as HDTV alternative to the standard cathode ray box like TVs. The primary driver behind a plasma TV is its sharp images and life-like colors. Anyone who has seen a plasma TV must have noticed the difference in shape as compared to the standard TV. Plasma TVs are wider than the standard TV since they are designed in the ratio of 16:9 rather than 4:3 ratio design of standard TVs. The goal of the wide TV screen is to accommodate for wider screen formats which are normally hidden in the standard TV or the screen height is reduced to accommodate the complete image, which in the process further reduces the size of the screen.

The plasma TV also relies on obtaining high quality inputs from broadcasts or DVDs. A plasma TV might need exactly be a cheap or cost-effective device. It may cost in the range of USD 4000 to USD 15000, although prices are falling every day.

Plasma TVs provide another great benefit for people who are running short of living space. The beauty is the plasma TV can be wall mounted. Generally people also like to combine Plasma TVs with a high-end home-theatre system with surround sound effects to create a theatre-like experience at home.

'Plasma' is a scientific term referring to gases like neon and xenon which glow when exposed to an electrical field. Plasma is sometimes called the fourth state of matter, after liquids, solids and gases. Think of a neon sign or fluorescent light bulb to understand plasma as it applies here.

TVs display color images based on thousands of pixels. Pixels are the small elements of pictures. Think of as a picture broken down into multiple pieces. Like any other color display technology, the pixels are made up of 3 basic colors, that is red, green and yellow. The mixture of these colors can create any color in the entire spectrum. Since the viewer is generally far enough from the screen, he cannot make out the individual pixels on the screen and the individual pixels fuse into one to create an illusion of motion as displayed to the viewer. This is true for all display technologies including, TV, computer monitor, the LCD display on the camcorder etc.

In a plasma TV, the individual pixels are made from three tiny containers of an inert gas such as neon or xenon. There are literally hundreds of thousands of these tiny tubes on an average plasma TV screen. All of these individual pixels are sandwiched between two electrically-charged plates. Remember that plasma glows when exposed to an electrical current. A computer processing unit receives signals from a cable or broadcast antenna which tells it how to reassemble the entire picture hundreds of times per second.

The computer controls the electrical field down to individual pixels, allowing different combinations of colors to glow. The viewer is usually not aware of all the changes, because his or her brain is processing all of the information as a continuously moving image. Because a plasma TV screen contains quite a few more pixels than a standard television, the image is noticeably sharper. Each pixel combination can reproduce an exact hue, not a quick approximation. This means the colors are usually deeper and richer.

The main drawback of a plasma TV system is vulnerability to damage. If a hard object strikes the screen, hundreds of individual gas-filled tubes instantly lose their ability to glow. Replacing all of those elements is a time-consuming and expensive process, if it can be done at all. Owners of plasma TV systems should always consider purchasing insurance and extended warranties, since the most common fix appears to be total replacement of the screen. Because the gas forming the plasma can leak or become less reactive to electrical charges, plasma TV systems do have a limited shelf life. It may take several years before a noticeable change in picture quality, but the cumulative effects are similar to what happens in neon and fluorescent lighting-eventually the gas inside the tube will begin to flicker instead of burning steadily.

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