Re:How is portable AM radio possible?
by Enginerrrd on Wednesday March 30, 2022 @02:47PM
(#30859248)
Not an EE, but my guess is Capacitors. Or at least one big enough capacitor. I think the capcitor responds to the EM fields out-of-phase with the rest of the circuit creating voltage differentials that can be measured. Not certain though.
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It's not entirely wrong to say that an antenna is a capacitor, but it's not a good way of thinking about antennas. The problem is that once you start working with radio waves, everything is a capacitor, everything is an inductor, and everything is an antenna.
With a capacitor, you have two plates and you design the structure of the plates in order to create a strong electrical field between them without leaking current between the plates or leaking the electrical field into free space. Antennas are designed the opposite way---not as a "big enough capacitor", but as an incredibly bad capacitor. Instead of holding a charge, the electrical field created by the antenna leaks into free space and is lost as electromagnetic radiation, or in reverse.
A good antenna is a bad capacitor.
That said, the antenna does have non-trivial capacitance and inductance.
It irritates me when people get downvoted for attempting an explanation from what they understand.
Re:How is portable AM radio possible?
by Dylan16807 on Wednesday March 30, 2022 @06:56PM
(#30861879)
Downvotes aren't a punishment. Marking wrong-ish things in gray is useful for discourse!