where to start

Here is a selection of excellent websites to offer you the hotest products in the high tech field. The field is so fast moving that Buy.com has a video webcast to keep you up to date. Look for Buy.tv.

LCD v. Plasma

Currently, flat TVs are created using two different technologies: plasma and Liquid Crystal Display (LCD). The foundation of the plasma TV is over a million tiny glass cells that are charged with a mixture of neon and xenon. Behind these cells are colored phosphors, which are chemical compounds that emit light when energized. Each cell has three phosphors; one red, one blue, and one green. When activated by an electrode, the plasma cells emit invisible UV light. The UV light strikes the red, green and blue phosphors on the back of the display and thus creates the pixels that form the image you see on the screen. LCD (Liquid Crystal Display) technology works differently. Liquid is suspended between two transparent panels. Within the liquid are crystals that, when activated by voltage, re-position themselves so that they either allow the light to pass through the panel and or block the light. This process is similar to turning on and off a million light bulbs. Fluorescent tubes behind the panels supply the light source. Both the lit and unlit crystals create visible pixels that cumulatively compose the image on the screen.

Pros and Cons of Each

Brightness
Brightness in LCD and plasma screens is typically expressed as candelas per square meter (cd/m2). Typically, plasmas are listed at 500-700 cd/m2, but independent reviewers say that that the brightness of plasma is closer to 100 cd/m2. Conversely, LCD TVs typically get a brightness rating of 450 cd/m2, again when measured independently.

Contrast Ratio
Contrast ratio is the measurement of the brightest white against the blackest black that the TV can create. The higher the contrast ratio, the easier it is to discern details on the screen. Current plasmas measure contrast ratios of up to 3000:1. However, independent reviewers believe that measured in real world viewing situations, contrast ratios for plasma TVs drop to approximately 200:1. Conversely, LCD TV contrast ratios range from 350-450:1 when measured using the same realistic standards.

Color Saturation
Color saturation describes the amount of grey in a color. The more grey, the lower the saturation. Plasma has the advantage over LCD in the area of color saturation because of it's method to light blocking. Plasma is able to completely turn off pixels when not in use, so that no stray light dilutes the colors. The way LCD technology works means that there is some stray light and therefore obtaining true color is difficult.

Screen Size
Right now, the plasma market offers TVs as big as 60 inches, and no plasma TV is available smaller than 32 inches. LCD screen sizes range from 13 inches to 46 inches, and because of manufacturing innovations, larger models are becoming available every year. Look for LCDs to catch up in this area soon.

Viewing Angle
Historically, plasma TVs have had a larger viewing angle, at about 160º, when measured against older LCD TVs. However, the newer model LCD TVs have viewing angles up to 175º degrees.

Burn In
Burn in is what happens when an image stays on a plasma screen for an extended period of time. LCD's are not at all susceptible to burn in. While Plasma TVs are vulnerable, some newer plasma TVs have added features that combat it.

Lifespan
Typical plasma TVs have a life span of 20,000 to 30,000 hours, which equates to at about 20 years of usage if you have the set on for 4 hours a day. The lifespan of an LCD TV is typically 50,000 to 60,000 hours, or about 40 years running 4 hours daily.

Response Time
Response time is the amount of time, measured in milliseconds (ms), that it takes for a pixel to go from active to inactive and back to active again. Lower numbers mean faster transitions and fewer visible image artifacts. Plasma TVs were made to handle rapid movement on the screen more effectively. They can have response times as low as 15 ms. LCD TVs started as PC displays, and so the need to show fast movement wasn't critical; somewhere around 25 ms. LCD manufacturers have been steadily improving their response times as the demand for fast moving, full motion video has increased. Newer model LCD TVs can have response times as fast as 16 ms.

Power Conservation
Because the crystals in LCD TV do not produce light, the technology is labeled as "non-emissive," which means it does not give off radiation like the CRT. Cold cathode light sources, like fluorescent tubes, which use only a little power, are used to illuminate the image. LCDs also use less power than plasma televisions, because plasma requires powering hundreds of electrodes to stimulate the phosphors.

Conclusion
Knowing that flat TV is not going away, there is no time like the present to start enjoying all the advantages that these new technologies. Check out Philips line of Plasma and Flat TVs online today.

Aspect Ratio and Widescreen TVs

It seems like everyone is excited about widescreen TV. Really, who wouldn't be-especially if you are someone who loves movies? But things get complicated when you start to hear talk of anamorphic formats and aspect ratios. What if you just want a great big picture?

What is Aspect Ratio? Aspect ratio refers to the relationship between the width and height of the viewing screen. A standard TV is 4:3, which means that it is four units wide by 3 units high. This breaks down into 1.33 inches of width for every inch of height, calculated by dividing 4 by 3. (You may see standard TV referred to as 4:3 or 1.33:1. Widescreen TV has an aspect ratio of 16:9, or 1.76 inches wide for every inch high (referred to as 1.76:1).

How Aspect Ratio Affects the Movies. If you are a film buff and want to watch movies at home that are in the same format that was shown on the big screen, consider this: movies made for cinema screens are filmed with an aspect ratio of between 1.85:1 and 2.4:1, and the director consciously uses the entire screen to tell you the story. So when a movie is re-packaged for television broadcast, various editing methods are used to try and make everything on the large movie screen fit onto a 1.33:1 TV. That means that 40-50% of the movie is affected.

Letterbox Format. Another way to get cinema-sized films onto a TV is using the Letterbox format. Most people have heard of this. Letterbox means that no editing was done to the film, but rather the way that the TV screen is manipulated to match the aspect ratio of the film. By adding a black area along the top and bottom of the screen, often referred to as "black bars," the TV screen is able to mimic the aspect ratio of the movie screen. While you don't necessarily miss out on any action, this is not always an ideal solution because on smaller TV sets, the narrow strip where the movie appears is even smaller, making it hard to see all the details. The bigger the TV screen, the less problematic the letterbox will be.

Widescreen to the Rescue. Perhaps the greatest thing about widescreen TVs is that they mean an end to the need for action-eliminating edits. Since the aspect ratio is of widescreen is closer to that found in movie theaters, there is plenty of room for the whole picture. However, because the aspect ratios do not match exactly, there may still be black bars around the movie (making it either letterboxed or sideboxed or both), but they will be narrower and therefore won't affect the image area as greatly.

And since more and more people are buying widescreen TV's producers are filming specifically for widescreen formats. That means that there is more widescreen content available than ever before. Since more and more TV stations are expected to be broadcasting digitally and the top digital format, HDTV, can supply an aspect ratio of 16:9, widescreen will soon be everywhere. It is likely we will see the ubiquitous 4:3 TV slowly replaced by widescreens. Philips has a large selection of widescreen tvs available online. View them now.

All that new HDTV widescreen content will be nirvana to widescreen owners. But there still be 4:3 content. What does 4:3 content look like on a widescreen TV? Anything you watch can be presented in multiple ways on widescreen because almost all sets feature different viewing modes that you can choose from. People develop their preferences. The modes generally include:
· Normal: When watching 4:3, you will see black bars on the sides to match the 4:3 aspect ratio.
· Zoom/Enlarge: This mode magnifies a 4:3 image, crops the top and bottom of the image, and removes the sidebox.
· Wide or Full: The mode most preferred for native 16:9 content, like DVDs, but when selected while watching 4:3 content, stretches the image horizontally, making people look shorter and fatter.
· Panorama (a.k.a. Theater or Natural): A combination of stretching and zooming to fill the screen. Manufacturers use different approaches to present this mode. Some TVs stretch the sides of the image more than the middle, so most people look normal, and some might crop just a little off the sides and not stretch as much.

Again, after experiencing all the modes, most people develop a preference depending on what content they are watching.

No matter what, having some understanding of aspect ratio and widescreen TVs can help you make the most of whatever type of TV you have and allow you have the best at-home movie watching experience possible. Philips has a large selection of widescreen tvs available online. View them now.

Electronics, security, automation & Internet

where to start