Using 4 tubes, this 1924 receiver combines new technologies as an intermediate frequency stage that was already beginning to appear. Listening is via phone and battery power.
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...