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.
Two operational are used on this triangular-rectangular oscillator suggested by Motorola in its...
This circuit from a Popular Electronics from the 90's can generate signals from 0.03 Hz to 3 kHz...
With 8 to 30 V power supply, the output power depends on both the voltage and the load. The...