This circuit is from a 1976 amateur radio manual. The transistor can be the BD136 and the frequency adjustment is done in a potentiometer. The supply can be done with voltages from 6 to 15 V.
We found this circuit in a 1998 documentation. The circuit can also be used as a minutery...
Found in a 1968 Electronics World, this circuit uses operational amplifiers from that time. |...
This circuit was found in a Radio Electronics issue from May 1989. Please note that it may not...