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 was found in the July 1992 issue of Radio Electronics magazine. The circuit is based...
This timer activates a relay after a time interval of up to 15 minutes has elapsed, starting from...
The circuit presented is based on a mechanical tuning fork. The circuit is suggested by National...