eli5: On old radios, how does turning the dial tune into a different station? what is happening inside the radio to achieve this?
In: 70
To tune into a station, there has to be something which naturally vibrates at the right frequency. This way, when the right frequency of radio waves hit it, it will easily vibrate, but other frequencies will not cause much vibration at all.
This vibration could be a lot of different things, such as a small quartz ‘spring’ that ‘boings’ at the exact right frequency.
Traditionally, instead of a physical object vibrating, you’d have an electrical circuit that does the same thing. Two electrical components are put together, one which acts like an electrical spring which pushes on electrons and one which acts like an electrical weight to slow down the vibration of the ‘spring’.
By making the spring stronger or the weight lighter, you can make the frequency higher.
If you make your electrical ‘spring’ tighter by pulling it apart (this would need its own eli5) it raises the frequency, tuning your radio to a higher frequency signal.
You could also make your ‘weight’ heavier or lighter. The easiest way to do this is to make a large coil (the ‘weight’) but connect your wire to different parts of the coil. By connecting to different parts of the coil, you’re effectively changing its length, which is analogous to its ‘weight’.
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