Television Work is an amazing window into the world. At the flick of a button, you can travel from the North Pole to the Serengeti. Watchmen walking on the Moon, see athletes breaking records, or listen to world leaders making historic speeches. Television has transformed entertainment and education in the United States.
It’s been estimated that children spend more time watching TV (on average 1023 hours a year) than. They do sitting in school (900 hours a year). Many people feel this is a bad thing.
Radio with Pictures
The basic idea of television is a radio with pictures. In other words, where radio transmits a sound signal (the information being broadcast) through. The air and television send a picture signal as well. You probably know that these signals are carried by radio waves, invisible patterns of electricity.
That race through the air at the speed of light (“bankomat“). Think of the radio waves carrying information like the waves on the sea carrying surfers. The waves themselves aren’t the information: the information surfs on top of the waves.
Television is really a three-part invention. The TV camera turns a picture and sound into a signal. The TV transmitter sends the signal through the air, and the TV receiver (the TV set in your home) captures the signal and turns it back into a picture and sound.
Television Work Cameras
We can see things because they reflect light into our eyes. An ordinary still camera photographs things by capturing this light on light-sensitive film or using an electronic light detector to make a snapshot of how something appeared at a particular moment. A TV camera works in a different way it has to capture a new snapshot over 24 times per second to create the illusion of a moving picture.
If you’ve ever tried copying a masterpiece from the wall of an art gallery into a notebook, you’ll know there are lots of ways to do it. One way is to draw a grid of squares in your notebook. Then copy the details systematically from each area of the original picture into the corresponding square of the grid.
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Television Work Transmitters
The louder you shout, the easier it is to hear someone at a distance. Louder noises make bigger sound waves that have the power to travel further before they get soaked up by bushes, trees, and all the clutter around us. Not everyone receives TV signals transmitted through the air in this way.
The same is true of radio waves. To make radio waves that are strong enough to carry radio and TV pictures many miles from a TV station to someone’s home, you need a really powerful transmitter. This is effectively a giant antenna (aerial), often positioned on top of a hill so it can send signals as far as possible.
Television Work Receivers
It doesn’t really matter how the TV signal gets to your home once it’s arrived, your TV set treats it exactly the same way, whether it comes in from an antenna (aerial) on the roof, from a cable running underground, or from a satellite dish in the garden.
Remember how a TV camera turns the picture it’s looking at into a series of lines that form the outgoing TV signal? A TV set must work the same process in reverse to turn the lines in the incoming signal back into a faithful image of the scene that the camera filmed. Different types of TV sets do this in different ways.
Cathode-Ray Tube (CRT) Televisions Work
Old-style, cathode-ray tube (CRT) TV sets take the incoming signal and break it into their separate audio and video components. The audio part feeds into an audio circuit. Which uses a loudspeaker to recreate the original sound recorded in the TV studio.
This fires a beam of electrons (fast-moving, negatively charged particles inside atoms) down a long cathode-ray tube. As the beam flies down the tube, electromagnets steer it from side to side.
Flatscreen Televisions Work
It’s quite hard to find cathode-ray tube televisions today. Since they’re based on analog technology and most countries are now switching to digital. CRTs are essentially obsolete (unless you use an adapter, called a set-top box.
That allows your CRT to pick up digital broadcasts). Most people have flatscreens instead, using one of three different technologies LCD, plasma, or OLED. LCD (liquid-crystal display) televisions have millions of tiny picture elements called pixels. That turns the sub-pixels on or off by twisting or untwisting.
