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.
The circuit we show is part of an article that taught its complete assembly. The article is from...
Found in American documentation from the 90s, this circuit has a timing system for activating the...
This circuit was obtained in a 90s Popular Electronics. It generates a 10 Hz sinusoidal signal...