This interesting reflex receiver used a different component, which at the time was showing up. The receiver is from a 1924 documentation and used a sodion tube.
This circuit is from a Radio Electronics magazine from August 1960. It is a commercial circuit for marine...
The Texas Instruments LM5178 Buck-boost controller is capable of operating in the 4.2 to 55 V (60...
This is a typical 80's FM radio mixer circuit. The circuit was found in a documentation of the...