How Radios Work
Almost everyone uses radios, but few people care about how radios work. We've had various versions of radios for more than one hundred years now, so our jaded attitude towards them is understandable. Still, it's good to acquaint yourself with this feat of technological ingenuity, if only as a way to impress people at parties. These are the basic things that are involved in making radios work:
Transmitter. A transmitter is a device that produces electromagnetic waves. All radios transmit signals through the careful altering of these electromagnetic waves. The quality and strength of these waves, and consequently the sounds heard from them, are affected by the amplitude, frequency, and phase of the electromagnetic waves.
Antenna. The electromagnetic waves are sent from the transmitter to an antenna. The station on the radio is the tuning of this antenna and the strength of the signal. The antenna works to convert the waves into the sound which your radio emits. This is, at its most basic form, how radios work.
Transistor. Transistors and vacuum tubes are crucial devices for strengthening weak signals. They aid in the reception and conversion of the electromagnetic waves.
Amplitude Modulation (AM). AM radio operates by having the radio microphone receive sound amplitude that is proportional to the amplitude of the transmitted signal. This means that the frequency that is transmitted is the same, but if you have a super powerful signal, you can actually broadcast worldwide. On the downside, the sound quality is worse because the reception of the signal is in such a raw form. The transmission can be affected by weather and other broadcasts.
Frequency Modulation (FM). FM radio is primarily different than AM radio because the transmitted frequency of the radio is, you may have guessed, modulated. This is accomplished by the microphone, which is responsible for the amplitude variation that modulates the frequency. This makes for higher quality sound that isn't affected by outside elements as much.
It is hard to summarize the complexities of radio transmissions. This is just the beginning step of learning how radios work. It would be a good idea to learn any unfamiliar terms here in order to better understand the process.