Question:How do infrared signals carry information to control electrical or electronic devices?
It is very similar to how light is used to send signals.
The infrared signal must be digital, and a digital code must be sent for every different command.
The signal must be digital because the amount of infrared received depends on many factors and relying on the size of the infrared signal to carry the information (as you do with an analogue signal) would be useless.
At the remote control unit, there will be an infrared emitter (a light emitting diode or LED for short), that emits infrared
At the electronic device there will be a receiver that sits waiting to receive a signal from the remote control.
When a signal is sent the LED flashes on and off in a sequence.
The receiver detects this sequence and converts it to an electrical signal that is interpreted by the device and a response occurs.