We found this circuit in a 1976 documentation. The FET can be BF245 or MPF102 and the power supply need not be symmetrical. The FET in the feedback acts as an automatic gain control.
This adjustable oscillator has the traditional configuration already presented in other articles. The...
This circuit appears in other versions on this site. obtained from other publications. This is...
This circuit decodes a 1800 Hz tone used in communications. The circuit is from an American...