Green TV
When sound was first sent over wires as electrical signals, people wondered if it might be possible to do the same thing with light. However it wasn’t until 1925 that the Scottish inventor John Logie Baird showed the first moving image transmitted as electrical impulses.
The fundamental technology he used to create the first useful television signal has changed very little. The light from an image is ‘rasterised’, or converted into pulses of electricity. It is then sent through wires or converted into radio waves and sent over a distance, where the string of electrical pulses is used to redraw the image on a screen.
Logie Baird used a spinning disc of spiral of lenses to capture a moving picture. Yet the picture was only 30 lines big – not enough to see many details. New technologies greatly improved the resolution of the images, so by 1929 Germany had regular broadcasts via television.
Today, most Australian households have at least one TV set. With cable and satellite transmissions, internet technology and plasma screens, the television has come a long way since those first silent, black-and-white images.
Unfortunately, these improvements have also increased their demand for energy. A large wide screen TV can suck up more power than your dishwasher, washing machine and dryer combined. Even when it is switched off, it continues to keep some of its circuits running.
TVs sold in Australia now need to have energy rating labels to make it easier for people to know how much electricity each TV set uses and to help them choose the most energy efficient model. You might have already seen them on refrigerators, dryers and washing machines. They also need to meet minimum standards which place a limit on how much energy an appliance can use in Australia. If a television doesn’t meet this standard, it cannot be legally sold.
Over two million televisions are sold in Australia every year, adding up to a lot of energy needing to be produced. Next time you upgrade your set, look out for the energy rating label. And remember – turn off your television whenever you’re not using it.