It is a simple crystal radio (3 components) connected to an op amp audio amplifier (4 components), plus an antenna wire, a speaker and a battery. Google “crystal radio” for a very large number of similar circuits.
Hi, guys… You guys are very smart. I am new to this electronics stuff. As much as it all seems fun and all… there’s a lot of underlying theory in there for a guy like me, for example, how would I know the thickness of the wire, the amount of turns for the wire, the theory behind selecting the right capacitor and inductor so you can receive a particular frequency and lots more…
I would love to buy a kit that not only shows how to build a radio like that, but with all the applied theory and mathematical equations would be nice I looked around and I saw kits that show this, but I am afraid to buy them because I may be disappointed due to the lack of theory they may miss out on. The nice things about electronics is not only to be able to build a circuit, but to also fully understand it. And that’s why I am afraid to buy certain kits 8)
For learning how radio stuff works the “ARRL Handbook” is pretty good. There are many used copies around so you can get one at a good price.
It covers most radio theory well. It also has equations to calculate LC vales for a frequency and tables to determine size and number of turns to make coils of a know inductance.
Us smart! Maybe, but really we just have been doing this a longer time.