Beginners Guide to a CRT TV

This hub is designed to give you a basic understanding to CRT televisions (Tube TVs). They were one of the most important inventions of the 20th century, with the CRT (cathode ray tube) television being the dominant TV type. This is now no longer the case with the assault from LED, LCD and plasma sets. Nowadays with most of the major retailers discontinuing the CRT models and very few manufacturers making them it is all too easy to forget how we got to the nice flat screen and slim line televisions we all take for granted today. I hope this hub gives you a grounding to the technology that created the original CRT TV.

The cathode ray tube works on a simple principal – a stream of electrons is fired at the back of the screen, which is coated with phosphors that emit light when the electrons hit them. By moving the electron beam over the screen (extremely quickly) a combination of light and dark pixels is created, forming a picture.

The process is repeated to produce the frames of a TV picture and the human brain does the rest, interpreting the series of still images as a moving picture.

Colour televisions use three electron streams and the screen is coated with phosphors that emit red, green and blue light. The different combinations of these make up all the colours on a TV screen.

Pros

• CRT sets deliver excellent images. Many people still prefer the picture on a CRT set to that of an LCD or plasma screen, especially for regular TV broadcasts

• The viewing angle on CRT sets (how far to the side you can sit and still see a clear picture) is excellent

• The technology has been refined over decades of use and prices can be low even for large-screen sets

• CRT sets have long lives and do not need professional installation like some alternatives

Cons

• CRT sets will not feature in the high-definition revolution due to hit the UK in 2006. This arena will be left to other technologies that are better suited to handling the extra image resolution of high-definition broadcasts

• They are very bulky when compared with plasma and LCD sets. The CRT itself is the villain here – it has to be big to do its job, and that means it takes up a lot of space in your living room

• They can be very heavy indeed, especially flatscreen sets, and this means you can’t easily move them from one spot to another

• Screen size is limited – a CRT screen can be no bigger than 36 inches (measured diagonally), while plasma sets have reached 103 inches and are still growing

• The picture can be distorted if home cinema speakers are placed too close (the magnetic field from the speakers can influence the electron beams in the CRT)

Want more information? Have we not been detailed enough for you?...

Click to view our Advanced Guide to How a CRT TV works.

Top tips for buying a CRT television

• Check inputs – if you have a DVD player with component video outputs you’ll want a TV with corresponding inputs

• Make sure at least one (and preferably more) of the Scart sockets is RGB compatible. You’ll need it to get the best picture quality from a satellite or cable digibox

• Check the screen ‘geometry’ – whether the picture bends at the corners. This is a drawback on most CRT sets, but some are better at handling the problem than others

• Opt for a flat screen if possible – they produce the best pictures and have less problems with geometry

• Be sure you aren’t interested in high-definition programming!

Component video – a high-quality video connection using three cables – essential for progressive scan images

CRT – Cathode Ray Tube. The technology inside a conventional TV, where electrons are fired at a phosphor-coated screen to generate images

High-definition – a superior delivery format for TV that presents more lines of detail, resulting in a much sharper, more detailed image. Due to launch in the UK on Sky in 2006

LCD TV – A television display that uses liquid crystals rather than light-emitting phosphors to create an image

Phosphor – A substance that generates light when excited by an energy source

Pixel – A ‘picture element’, the little dots that make up an image on a screen

Plasma TV – A flatscreen TV that utilises plasma to stimulate phosphors, rather than a stream of electrons (as in a CRT TV)

Progressive scan – A method by which image detail on a TV picture is enhanced by showing both halves of a single frame at the same time, as opposed to showing only half a frame at a time

Viewing angle – The range within which a watchable image is retained. Stray outside the viewing angle and the picture begins to fade

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