Television is an incredible window to the world. Whether you’re a TV addict or only watch the occasional programme, there can be no doubt that it’s an amazing invention that has transformed our lives. So, how does these devices actually work?
When it comes to transmitting waves strong enough to carry sound and images over large distances, you need an extremely powerful transmitter. If you’ve ever noticed huge antenna located on the tops of hills, then they help to carry waves across many miles from a TV channel into your home. Cable television works slightly differently, and images are piped into your home through a fibre optic cable under the road. Satellite TV is different again, with the image you see having been bounced off a satellite in space and back down to your TV.
Older TV sets received analog signals along an undulating wave, whereas these days most transmissions are digital – sent in a numerically coded format. A better picture is achieved this way, as there is less atmospheric interference. If you need help with your set, contact a professional TV Aerials Swansea firm like https://www.onevisionltd.co.uk/tv-aerial-installation-swansea
However a signal arrives in your home, any TV responds in the same way to it. A TV turns an image from a series of data back into the original image and different sets do this in different ways.
Cathode-ray tube televisions
In the past, cathode-ray tube TVs would receive the incoming signal and separate it into audio and visual components. The audio and video were sent to different circuits, firing electrons down a cathode-ray tube. As the beam of electrons travel through the tube, they move are steered by electromagnets from side to side, scanning the image and reproducing it line by line. It all happens so fast that you don’t see the electronic picture being built.
Today we are more used to seeing LCD televisions that contain millions of miniscule elements called pixels. These pixels can be turned on or off to make images. Each tiny pixel consists of green, blue and red sub-pixels that can be turned off individually by liquid crystals. There is no cathode-ray tube, so LCD screens can be smaller and more energy-efficient than the early TV sets.
Plasma operates in a similar fashion to LCD, but each individual pixel is a tiny fluorescent lamp that glows with plasma, a very hot gas. The gas particles are freely moving and create a light glow whenever they collide. Plasma screens can be produced to be a whole lot bigger than the traditional cathode-ray tube sets but are also significantly more expensive.