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.
Found in an Electronic Design from the 90's, this circuit uses common components. The circuit is...
With this circuit it is possible to modulate a small signal in amplitude using a common germanium...
This circuit is from the 80's integrated circuit manual itself. The component is not as common today...