This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms and excites a load of 16 ohms. The integrated circuit of the time is the PA237.
This circuit produces a square wave signal with the frequency determinated by R1 and C1. The upper limit...
The FET can be a BF245, and the other transistors can be the BC548 and BC558 in this simple AM...
In this circuit, from a 1977 publication, we have the traditional version of a filter tuned to 1...