Television is a way of sending and receiving moving images and sounds over wires, or through the air by electrical impulses.
In a TV camera, thousands of light- sensitive detectors are arranged in a grid. Each detector is called a picture cell, or pixel. As light falls on each pixel, it produces an electrical signal. the signal form each pixel is sent down a cable in the form of a long coded message.
At the same time, a microphone records sounds that are occurring during the scenes. A vibrating magnet in the microphone changes these sounds into electrical signals too. When a programme is broadcast, the electrical signals are turned into invisible bands of energy called radio waves that are picked up by a television set. The television set then changes the waves back into pictures and sounds.
Do you know how colors appear on your TV screen? The television screen is covered in rows of tiny pixels. Each tiny pixel can be made to glow. The pixels are red,green and blue- the primary colors of light. When the red, green and blue pixels glow together, our eyes see the color white. Similarly, different colors are produced on the screen when different combinations of pixels glow. The brightness of each pixel can be altered too, giving a greater range of colors and shades.