The television set is commercially available since late 1920s and has revolutionized every aspect of modern life. A source of entertainment, advertising and news, you can find a TV in homes, institutions and basically everywhere. But how does a TV work?
Most television sets have the same principles and create the illusion of movement by sending images that change fast. Although televisions can transmit pictures at a distance, they are not sent through the air but instead converted into electrical impulses at one end and changed back at the other end.
The picture is captures by a camera lens that breaks into a series of dots or pixels. There are 1920 dots in a string and 1080 lines in an high definition signal. The picture is then focused on a light sensitive plate of glass that throws out electrons. In the brighter areas it throws out more electrons than in the darker ares. The electrons are collected on a target plate and an electron gun throws a beam on the plate. The scanning beam sweeps back and forth 30 times in one second so that it covers the entire surface of the target plate. The return beam is modulated according to the area it strikes and sometimes it is strong and other times it is weak.
The beam that bounces back goes to an amplifier as electrical impulses and then it reaches the television station transmitting tower. It is sent out to the receiving end where it get picked up by an antenna. The electrical impulses then go into an amplifier in the TV set and are sent to the electron gun. The gun send a beam back and forth across the screen scanning the lines. Because the screen is coded with phosphorus, it gives out light when the beam strikes it and the original image forms.
But how does a TV work across the continent? Radio and television signal are transmitted from one continent to another by communication satellites orbiting the Earth. They are equipped with receivers and transmitters so the signal can be picked up from the ground station. Electronic devices increase the strength of the broadcast signals and the transmitters send it to a ground station on another continent. The first satellite that made a direct television connection possible between Europe and the United Stated was Telstar 1, launched in 1962.
If you are wondering how does a TV work with high-definition technology, the answer is simple: it just holds more pixels and display progressively, showing them all at once.