Described in an article in the March 1979 issue of Radio Electronics magazine, this generator was used in an audio test station. The frequencies are given by the capacitors.
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
We found this circuit in documentation from the 1980s. The transistors can be the BC558 and the...
The input resistance of this circuit is 60k and the pass band from 20 to 20kHz. The circuit is...