This receiver was found in a 1924 book by Gernsback. The circuit uses three tubes and is powered by 3 batteries of different voltages, common at the time.
This basic configuration can be found in a lot of articles on this site. In this case, the relay...
This circuit was found in a 1997 publication, but it uses few common components and is very...
This circuit prevents the passage of frequencies in a range starting at 1 kHz and can be adjusted...