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Q.
What is a Plasma Television?
A. Plasma television technology is similar
to the technology used in a fluorescent light bulb. The display
itself consists of cells. Within each cell two glass panels
are separated by a narrow gap in which neon-xenon gas is injected
and sealed in plasma form during the manufacturing process.
The gas is electrically charged at specific intervals when
the Plasma set is in use. The charged gas then strikes red,
green, and blue phosphors, thus creating a television image.
Each group of red, green, and blue phosphors is called a pixel
(picture element).
This technology is different from
that of a traditional television. A traditional television
has a Cathode Ray Tube, or CRT. A CRT is basically a large
vacuum tube in which an electronic beam, emanating from a
single point in the neck of the tube, scans the face of the
tube very rapidly, which, in turn lights up red, green, or
blue phosphors on the tube's surface in order to create an
image.
The main advantage of Plasma over
CRT technology is that, by utilizing a sealed cell with charged
plasma for each pixel, the need for a scanning electron beam
in eliminated, which, in turn, eliminates the need for a large
Cathode Ray Tube to produce video images. This is why traditional
televisions are shaped more like boxes and Plasma televisions
are thin and flat.
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Q.
How Long Do Plasma Televisions Last?
A. Even is a plasma television has half-life
of about 30,000 hours (most newer units have 60,000 hours).
This means that it will lose approximately 50% of its brightness
during that time. Based on a 30,000 hours rating, if your
Plasma television is on for 8 hours a day, its half-life would
be about 9 years - or, if on 4 hours a day, the half-life
would be about 18 years (Double these figures for a 60,000
hour half-life). In addition, Panasonic has announced (with
others sure to follow) that it has attained a 100,000 hour
half-life capability for some of its Plasma sets. This means
that if you watch TV 6 hours a day, you will have an acceptable
viewing experience for about 40 years. Even at 24 hours a
day, a 100,000 hour half life is still about 10 years. In
any of the above cases, a Plasma Television can provide many
years of satisfying viewing.
Keep in mind that a standard television
loses about 30% of its brightness after about 20,000 hours.
Since this process is very gradual,
the consumer isn't aware of this effect, except for the need
to periodically adjust the brightness and contrast controls
to compensate. Although the performance of individual Plasma
televisions can vary, overall, as a product class, a Plasma
television can deliver many years of acceptable viewing.
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Q.
Do Plasma Televisions Leak?
A: For optimum viewing, your eyes should be about level with
the middle of the screen when you're seated in your normal
viewing position. This is especially important for "big-screen"
rear-projection TVs since their pictures will look most vivid
at this level. We carry a wide selection of TV stands to support
flat-panel and tabletop rear-projection TVs, and to raise
them to the correct viewing height.
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Q.
Can a Plasma Television Work at High Altitudes?
A. Decreasing external air pressure present
at higher altitudes can be a problem with plasma Televisions.
Since the pixel elements on a plasma television are actually
glass housings containing rare gases, thinner air causes greater
stress on the gases inside the housing. Most Plasma Televisions
are calibrated for optimum operation at, or near, sea level
conditions.
As altitude increases, the Plasma
Television needs to work harder in order to compensate for
the difference in external air pressure. As a result, the
set will generate more heat and its cooling fans (if it has
them) will work harder. This may cause the consumer to hear
a "buzzing sound". In addition, the previously mentioned
30,000 hour half-life of the Plasma screen will be reduced
somewhat.
One way to check this out, if you
live in a high altitude area, is to check out Plasma Televisions
at your local dealer. While you are there, put your hand on
the unit and compare the warmth from the extra heat generation
and listen for the tell-tale buzzing sound. If it turns out
that a Plasma Television is not acceptable in your geographical
area, you might consider an LCD flat panel or a thin DLP projection
set instead. On the positive side of this issue, as more and
more consumers from all geographical areas demand access to
Plasma Televisions, units specifically calibrated for higher
altitude use will become more common.
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Q.
Are All Plasma Televisions HDTVs?
A. The short answer to this question is "NO".
Here is why:
In order for a Television to be classified
as an HDTV or HDTV-ready the television must be able to display
a vertical resolution of at least 720 lines. Some of those
"budget" Plasma televisions that are "selling
like hotcakes" only display a vertical resolution of
480 lines. These sets are referred to as EDTVs (Extended or
Enhanced Definition televisions).
EDTVs typically have a native pixel
resolution of 852x480. 852x480 represents 852 pixels across
(left to right) and 480 pixels down (top to bottom) on the
screen surface. The 480 pixels down also represent the number
of lines from the top to the bottom of the screen. This is
higher than standard television, but not HDTV resolution.
The images on these sets look great, especially for DVDs and
standard digital cable, but it is not HDTV.
Plasmas that are capable of displaying
HDTV signals have a native pixel resolution of 1024x768 (where
768 also represents the number of lines from the top to bottom
of the screen) or higher.
Since Plasma televisions have a finite
number of pixels (referred to as a fixed-pixel display), signal
inputs that have higher resolutions must be scaled to fit
the pixel field count of the particular Plasma display. For
example, a typical HDTV input format of 1080i needs a native
display of 1920x1080 pixels for a one-to-one point display
of the HDTV image. However, if your Plasma television only
has a pixel field of 1024x768, the original HDTV signal must
be scaled to fit the 1024x768 pixel count on the Plasma screen
surface. So, even if your Plasma television is classified
as an HDTV because it displays 1024x768 pixels, some HDTV
signal inputs will still have to be scaled down to fit the
Plasma Televisions pixel field. By the same token, if you
have an EDTV, any HDTV signals will have to be scaled down
to fit an 852x480 pixel field. In essence, the resolution
of the image actually viewed on the screen does not always
correspond to the resolution of the original input signal.
In conclusion, when selecting a Plasma
Television, make sure you check to see if it is an EDTV or
HDTV-ready unit.
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Q.
How Come Plasma Televisions Are Shaped Differently Than Analog
Televisions?
A. Plasma televisions are made in the 16x9
screen aspect ratio in order to accommodate widescreen DVD
and digital television broadcasts. Standard television 4x3
broadcasts will we shown with black or gray bars on the left
and right sides of the 4x3 image. Some units may have a 4x3
to 16x9 image expansion circuit, but this may introduce a
slight shape distortion to a 4x3 image when expanded all the
way to the sides of the 16x9 Plasma display.
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Q:
Do Plasma Televisions Generate Heat?
A. Yes, since one of major components of
a Plasma television is charged gas, the set will be warm to
the touch after being in operation for a while. Since most
Plasma televisions are wall or stand mounted, with plenty
of air circulation, heat generation, under normal circumstances,
is not an issue (refer to previous question on high-altitude
use). However, along with heat generation, Plasma TVs do use
more energy than a standard CRT set.
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Q.
Will a Plasma Television Work With My Old VCR?
A. A plasma television made for consumer
use will work with any existing video component with standard
AV, S-Video, or component video outputs. The only cautionary
note about using it with a VCR is that since VHS is of such
low resolution and has poor color consistency, it may not
look as good on a large Plasma screen as it does on a smaller
27-inch television.
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