How does a colour TV Function?
Working of a colour TV
A TV is an electronic device which produces audio and visual effect simultaneously. It is not only a means of entertainment but also a great source of education. TV’s are of two types: Black and white and colour. Colour TV functions quite like a blacke and white TV set its working is much more complex. The colour TV has mirrors inside the camera whish divide the light into three parts. There are three filters inside the camera, one for each part of the light. One filter allows only red light to press, another allows only green and the third only blue. Each colour goes to a different camera tube and each tube has a separate glass plate and electron beam. From the three tubes three signals go to the transmitter. The colour TV transmitter multiplexes three signals into one.
To this resulting signal a black and white signal is added. This combined signal is sent to the broadcasting antenna. In colour sets three electron beams- red,green and blue, scan the screen which when mixed together give full colour picture. The screen of the picture tube is coated with 1-1/4 million tiny dots of phospher each arranged into a group of three. A phospher is a substance that emits light when an electron beam falls on it. Each of the three phosphers emits three colours-red blue and green. So the blue phospher emits blue light when the electron beam carring the blue light signal falls on it and so on. The colour produced at each group of dots depands on the intensity of the electron beams. To make sure that each beam produces the right colour, the beams pass through holes in a shadow mask behind the screen. These three colours can be produced in different proportions to give all the other colours of the original. In a modern TV set all its functions can be regulated by remote control system which includes sound adjustments colour perfection, channel changing and so on.