This active tone control circuit was found in American documentation from the 90's. The transistor can be general purpose or low noise with high gain.
We find this circuit in a manual of the 80's own used components. The circuit provides an...
The frequency of this oscillator depends on the capacitors, being able cover the range between 1...
Hartley oscillator operates in the audio range. Frequency can be adjusted by P1 and also depends...