Televisions detect radio signals. Remote controls transmit infrared signals.
How Does TV Work?
There are three general types of television service providers: broadcast, satellite and cable.
- Broadcast TV companies send their signals through the air, much like controllers send commands to toy remote control cars. To make sure their signals reach as many homes as possible, they're usually sent from tall transmission towers, located on mountaintops, buildings or other high places.
- Satellite TV providers also send electronic signals through the air – except instead of using transmission towers, they send them from satellites that orbit Earth in space.
- Cable companies send their signals through a thick wire that leaves the cable company and splits into thousands and thousands of additional wires that each connect to someone’s home. The process can be compared to a tree’s method of getting water from the ground and sending it through its branches to reach every leaf.
Homes that have broadcast TV service get the electronic information through an antenna; homes with satellite service get it through a satellite dish; and homes with cable get it through the underground wire that started at the cable company. All three of these methods then connect to TVs directly inside the house.
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When you turn on a TV, the information it’s being sent tells it how to put the pictures together so it looks like the movie or show you want to see. It's similar to creating a picture with a paint-by-numbers kit, except TVs use colored pixels instead of paint. The TV also puts the sound together. This all happens very quickly, because to make people in a group of single pictures look like they’re moving, the TV has to show 24 pictures every second. That means when you watch a half-hour TV show, you see 43,200 pictures!
How do Remote Controls Work?
Say you want to turn up the volume on your TV. You press a button on the remote. The little microcontroller (which is just a tiny computer) in the remote wakes up, and reads which button you have pressed (“volume turned up, please”). It then creates a packet of data – a message – in a language the TV can understand. It sends the message via an infrared light to the TV, assuming you aimed the remote correctly. That message is then picked up by the infrared TV receiver, which decodes it (“ahh, he wants the volume turned up, ok.”). Then the small microcontroller (a tiny computer) in the TV makes the necessary changes to the volume.
Topic Tips
- Televisions detect radio signals. Remote controls transmit infrared signals.