How stuff works: your TV

Have you ever wondered how your TV works? We delve into how these miraculous marvels of modern technology work and look at how you can make sure your TV is as energy-efficient as possible.

TVs are a huge part of modern Australian life. They inform us, entertain us and are a staple appliance in most lounge rooms across the country. They also happen to be one of the biggest contributors to energy bills in most homes. Given there are over 18 million TVs in private homes across Australia we thought it might be worth delving into how they work and how to make sure they’re not using excess energy.

Put simply, TVs are incredible inventions. They are the culmination of a huge range of scientific discoveries and technological advancements, from the harnessing of electricity to the transmission of data via radio waves and the manipulation of liquid crystals to make pictures.

Let’s start from the beginning:

Our brains

To explain how TVs work, we need to start with our brains. TVs work on the simple (but amazing) principle that human brains can make sense of collections of small dots gathered together and turn them into functional pictures. TV screens are essentially just collections of tiny, different coloured dots. Add to that the idea that if you cycle through a series of pictures quickly enough the brain will interpret it as movement and you have the foundation for TV.


Video is essentially a collection of photos displayed and in a sequence and cycled through at a pace that gives the impression of movement. Video is a more elaborate version of those flipbooks you had when you were a kid. Over the years we’ve got really skilled at working out what the right speed to flick through the images is to ensure that they don’t feel jumpy or the images don’t feel too fast to represent real motion.

Tube TVs

The original TVs had something called a cathode-ray tube in them. This tube, at the back of the TV shoots little beams of red, blue and green light  at chemicals in the screen at the front which turn the light into little red, green or blue dots. The lights run in across and down the screen incredibly quickly giving the sense that all of the dots are lighting up at once when in fact only one small part of the screen is lit up at any given time. These dots are all merged together in our brain to form pictures that we can interpret.


These are the lovely flat TVs we all have on our walls now and they work in a different way to tube TVs. LCD TVs have one light at the back of the TV. At the front of the TV in the screen they have millions of liquid crystals that can be turned on and off to filter the light into different colours of red, green and blue making images that our brains can interpret.


Video cameras capture images in fast moving lines of light separated into the colours red, green or blue. The pattern made by the different coloured lights is then turned into an electrical signal, merge together and then combined with an audio electrical signal. In modern cameras the signal is turned into a series of ones and zeros, in the same way computer code is. This code is then sent to a transmitter.


The code for TV signals sent to the transmitter in the form of an electrical signal is then amplified through a transmitter and sent out into the world as electromagnetic radiation. The radiation can be picked up by your TV aerial and then converted back into code which tells your TV what colour it’s various liquid crystals should be at any given time to make pictures.

TVs are complex and incredible beasts. Fortunately understanding how to save power with them isn’t. How much power they consume really depends on the size of the TV, whether it’s LED or plasma (we won’t even go there with ‘tube’ TVs). Generally LED LCD TVs are considered to be the most energy efficient TVs to run and the smaller they are, the less energy they consume.

Apart from sizes there’s also a few other factors you can take into considering when trying to reduce the energy consumption of your TV.

  • Standby power: Your TV isn’t really off when it’s in standby mode. It’s still consuming power. Find out more about standby power, the energy vampire in your home.
  • HD: LCD TVs with higher definition basically have more liquid crystals in the screen. The more liquid crystals, the more energy you need to change their colour.
  • Screen brightness: Brighter TVs need brighter lights in them. More energy equals brighter lights in the TV.
  • Volume: Although it’s not a big energy consumer, using a higher volume can up the amount of electricity your TV uses.

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