- TL;DR Summary
- What is the difference between a variable capacitor in a AM receiver and a variable capacitor in a FM receiver?
What is the difference between a variable capacitor in a AM receiver and a variable capacitor in a FM receiver? I understand that Am is amplitude modulation and that the signal is carried over a changing amplitude and that the frequency is constant. And the opposite in FM signals. And a variable capacitor is a capacitor which you can change in order to match the signal you want to receive. When an antenna receives a FM wave the currents acceleration will change according to the absorbed wave and when an antenna receives an AM wave the acceleration of the charges will be the same but the amount of „electrons“ that get accelerated are larger. Thus the voltage over the capacitor changes. So I can kind of understand that you can have a capacitor and tune it in to the right amount of electrons that get accelerated in the FM case, since the amplitude is constant and thus the amount of electrons that will „build up“ on one side of the capacitor. Am I thinking correct? But how does a variable capacitor work in the AM case, when the frequency is constant?