This circuit uses two diodes in a doubling configuration to receive medium-wave range signals. The phone is crystal. We found it in a 1968 American documentation.
This circuit is from a 1967 documentation. It consists of a sensor for memories used at the time....
We found this circuit in the November 1992 issue of Radio Electronics magazine. The circuit has...
Found in EEE documentation, this circuit can have the duration and frequency adjusted separately....