Plasma TV's are essentially charged gas cells (pixels) where the charged gas strikes Blue/Green/Red phosphors, similar to a regular CRT tube where charged electrons strike Blue/Green/Red phosphors on the CRT inner face. The technology is different, but the principle is the same. Since the Plasma TV does not involve scanning charged electrons over a relatively long distance to the screen, it can be made very thin relative to a CRT tube. Plasma TV's have some problems similar to CRT TV's in that you can get phosphor burns and static images on the screen if the phosphors are exposed to one pattern over a long time. Plasma TV's also consume more power and are hotter to the touch. They are also heavier. On the positive side, they tend to have better color depth, contrast ratio, blacker blacks, and more rapid response time (less motion smearing).
In general, LCD TV's have almost opposite the characteristics of the Plasma TV. Cooler, less power consumption, no burnin images, not as heavy, less contrast ratio, less color depth, longer response time, etc. LCD TV's require a backlight, generally a cold cathode tube or flourescent light. If it goes out, the entire picture is lost until it is replaced. But individual pixels can also fail, leaving a very tiny "hole" in the picture which cannot be fixed.
LCD TV's have advanced by offering faster image refresh rates - from 60Hz to 120Hz, and now 240Hz. The faster refresh rate helps reduce any motion smearing in the image.
Currently Plasma TV's cost less than LCD, and are available in larger screen sizes.
LED TV's currently are not Red/Green/Blue LED based pixels. Rather, the backlight of the pixel is a white LED. All the LED's are tightly controlled for the same color temperature and brightness, yielding a very uniform backlight which can also be intensity controlled. This innovation provides better contrast ratio, color depth, and blacker blacks than non-LED backlit TV's.
In general, advances in LCD TV's have resulted in much smaller pixels (translates into more pixels on the screen and higher resolution of the picture). Price differences have also been reduced.
So, if you can afford the price, the choice should be based on how you watch TV...e.g. a lot, or not, High Definition or not, movies vs. regular TV, do you hook a computer to it, etc.
My personal choice is LCD. Since I have an older one, it is 60Hz refresh and 37". My next LCD will be minimum 120Hz refresh rate, LED backlit, and probably 55". I personally do not see enough difference between the 240Hz and 120Hz refresh rate for how I watch TV. If you watch a lot of high speed action sports, go for the 240Hz refresh rate.
Hope this helps,
I liked your comprehensive response to the questions about LCD and Plasma HDTVs. I have a Lenovo laptop that only has a 9-pin VGA monitor output and my Sharp HDTV does not have this type of input. Have you used any of the laptop to HDTV "wireless" transmitters available today to view A/V material (e.g., YouTube, online TV shows) from the web on your HDTV? I have a Wi-Fi set-up at home that works well. In fact, streaming Netflix video via the Roku receiver I have looks great and has 720p resolution without interruptions. Any suggestions for a good laptop VGA or "USB 2.0" to HDTV wireless transceiver?
Many Thanks, Mel
I am sorry, but I have not tried any laptop to HDTV connections. It should be very similar to connecting a laptop to an outboard projector. A cable is run from the laptop to the projector, then at the computer you can use ALT-F7 (I forget which exactly) and choose the display mode for 2 monitors. One will be the laptop screen itself, and the other should then be the HDTV (provided it has an PC input mode). I am sure you know this already. However, I would have thought you could get a 9-pin to 15-pin adapter cable somewhere without having to go a "wireless" direction. I never ran into the problem before. I have no experience with any product for this purpose other than a cable interconnect.
If I get a chance, I may try this over the weekend as I need to take my laptop to a location where there is a small isolated HDTV that does have PC input. But if my memory is correct, everything is 15 pin interconnects.
Hi Ken, Many Thanks for your kind research and the info you provided.
Turns out that the VGA output from computers is analog in nature and not directly compatible with the digital HDMI input of HDTVs.
And, since I want a "wireless" connection, I found that there are a few VGA to HDMI transceivers available, but I was wondering if you had any experience with them (and you did not not---no problem). All the Best, Mel
It may be worth checking into different set top boxes that will take streaming video from a computer and display it on your TV. This works great for things like videos and such you have on your computer. Not so sure it would work all that well if you want to display your actual computer screen onto the TV and operate the computer from there.
Many of the major game consoles (PS3, XBox, etc) will allow this either natively or with some "tweaking" done. And I know there are a few other types of devices that do it, but I'm not really up on the subject.
But I think you're looking for more of a pure adapter cable type of thing and for that I'm not really sure. The issue of the analog vs digital is probably going to be the big issue with finding such a device that would work well.
If you do come up with something please post it hear as I wouldn't mind having that as well. Could certainly come up with some nice uses for some older computers if there's an easy (and not expensive) way of doing it.
Yes, I heard of the PS3 and XBox working as laptop interfaces to an HDTV, but I don't own either of those gaming consoles. However, there are a couple USB 2.0 to HDMI "wireless" transceivers on the market today. They seem to have mixed reviews however. Below are the weblinks for your info and/or investigation. Please let me know if you find a good solution. In my case I have a Lenovo laptop running Windows XP 2nd Ed with VGA and USB 2.0 ports.
Have you come across a camera with timer that capture snapshots of the sky every 5mins? It is used for weather study purpose therefore have to withstand changing tropical climate conditions. One additional feature is to transfer the photo images to a pc for processing either wirelessly or through a cable. Is a microcontroller up to the task of image processing, recognise cloudy, sunny or rainy weather?
Hello Mr. Tan,
I have not come across any specific webcam that has onboard timer capabilities.
In general, most all webcams can be connected to a PC, Some use USB, and others offer wireless links to the PC. Depends upon the supplier. Logitech offers a wide range of webcams, but they are not the only supplier. Linksys is also good.
The key to using a webcam the way you want will be the software that you use. There are many software programs out there for interfacing with webcams. Almost all of them allow periodic capturing of images, and some means of storing them on your PC or uploading them to a image server on the internet so that you can monitor the camera images from anywhere.
As for "weather recognition", there may be some specialty programs that do that. I don't know of any, but possibly a specific Google search will turn up one. Many of the webcam software packages offer motion detection as an option to trigger a photograph (think security camera software). Clouds moving across the scene could trigger a photograph, for example, and might indicate some gross change in the weather. Light changes may be could be used as well.
Since I don't have any experience with the particular type of application you want to do, I cannot advise any particular solution.
But, if you want to experiment with a webcam and software, I would suggest you buy a wireless Linksys camera (http://www.linksysbycisco.com/LATAM/en/products/WVC80N ) and use a software package called "Yawcam" (http://www.yawcam.com/ ) which is a freeware package written in Java. This will quickly allow you to learn what the capabilities of webcams are. If you like what you see, you may also contact the software developer and find out if you can get access to the Java source code and then modify the software for your use. It is worth a try.
Hi do you have any information about any product based on BU9458 or BU9457. This is very interesting chips for MP3 decoding controlled by I2C from Romh. I need information if any succesfull product is based on this chip but I need independant opinion (not from Romh) about these chips. Best Regards Alex
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Ken has 40 years of experience and his expertise spans the multimedia, communications and consumer electronics industries. He has a personal interest in audio and multimedia related subjects.
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