This circuit is from a 60's documentation. The capacitance C1 can be between 20 pF and 0.01 uF depending on the generated frequency. Equivalent transistors may be employed.
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...