How does a Television work regards to physics (electromagnetic wave, image rendering, cathode ray tube, etc.)

Eduardo Miguel Breijo Baullosa

In today’s advanced and developed world, television plays a vital role for the efficient and effective development in the field of communication it. Not only this, it has also become the part of entertainment in our life. At present context, we are fond of it but the saddest thing is that, most of us even don’t know how it works. We are only concerned to use it but we are never concerned to know about it practically. That is the main problem within us of being in a back position. Anyways, we all of us must know what Television is so that we must not sit quiet when someone question us about it.

Actually, television is a telecommunication medium for transmitting and receiving moving images that can be monochrome i.e. black and white, or colored or without accompanying sound which produces a series of tiny dots on screen that appears as an image when it is seen as whole. Most of the kinds of television work from the basic principle. A tube-type color television has three colored light guns behind the screen which are red, green and blue where strong magnets sweep the single beams back and forth across the horizontal rows from top to bottom in a lawn mowing pattern which is repeated 60 times every second to create the illusion of a solid moving picture. And, then the three colors get mixed to create any color on a tiny dot of lights on the TV screen called pixels which flashes according to a specific pattern provided by the video signal. A person’s eyes transmit this pattern to the brain, where it is interpreted as a recognizable image. The refreshing speed of patterns by television is hundreds of times per second that is faster than the view of human eye which gives the illusion of movement.

In older days, televisions rely on Cathode Ray Tube to produce images and operate analog signal which are commonly called CRT televisions. These television uses an evacuated glass envelope which is large, long from face screen to rear end and is quite heavy whose main work is to deflect and accelerate the electron beam onto the fluorescent screen to create fine images and it is the main reason which helps in rendering images in the television by emitting the light which is not visible to naked eye.                               

An analog television works by transferring electromagnetic waves into sound and light energy where TV box works like any receiver which takes electrical impulses in, sent from elsewhere and changes those bits of information into something which can be seen and heard by the people. Color televisions are created by mixing several beams of light which primarily works by regulating red, blue and green light in different patterns against called “phosphor sheet”. All the TVs have these sheets placed behind the glass portion of it. The difference is only that Black and White televisions have only one sheet whereas color televisions have three phosphor sheets which help for television to work instantly.

Nowadays, as technology has advanced and broadcast signals, discovery from analog to digital, plasma and LCD (Liquid Crystal Display) are developed which have more compact and have crisper images than their cathode ray counterparts because they use thin grid of pixels to create images rather than a vacuum tube. We all are waiting for further development of different kind of televisions in order to be facilitated and entertained by various ways.