We found this transistorized circuit in a 1985 documentation. The circuit can operate with voltages from 9 to 12 V and the adjustment of the operating point or input sensitivity is done in P1.
This 1/2 hertz high selectivity filter was found in the December 1990 issue of Radio Electronics...
The frequency in this circuit is adjusted by P1 and given by C1. Short pulses, as the ones...
This Hartley telegraphy oscillator operates with the transmitter signal generating a tone in a...