when you touch a button, it completes a circuit in the remote. This allows a series of light pulses to be let out. Each button will have its own ‘code’ made up from the pulses.
An infrared light receiver on the TV will then convert the light into electrical pulses. The electrical pulses affect the microprocessor in the TV and gets it to follow the command you made by using the remote.
Dalya’s right, but the “light” is actually infrared light, which is why we can’t see it.
But hey, here’s a great little experiment you can do…
If you know of someone with a digital camera (in fact even some mobile phones have cameras in them), then you might have one where you can see the image before you actually take the picture. This is great because it lets you see the scene move about, so you can line it up just right.
But there’s something else neat about this.
A digital camera uses a special light-sensitive chip called a CCD. These CCD chips are sensitive to light, which is why they work, but they are also sensitive to a bit of infrared light.
So, here’s the experiment…
Switch a camera or mobile phone on so you can see the image moving around.
Put the remote control in front of the camera, with the little dot at the front of of the remote pointing back at the camera camera lens. Press a button on the remote control.
Assuming the batteries aren’t flat, you will see the pulses of light that Dalya was talking about coming from that little dot on the remote control. Even though YOU can’t see that infrared, your CAMERA can. (Don’t worry, the remote control will not hurt either you or the camera doing this experiment.)
An encoded infrared signal is sent when you press a button on your remote control, this is received by the front of your TV, decoded and then the appropriate action is performed e.g. increasing the volume or changing the channel.