This circuit was found in a 1964 documentation. It shows how to achieve automatic gain control for an oscillator. The transistors are of the time and the circuit controls signals from 2.6 to 3.1 kHz.
This circuit is suggested by National Semiconductor and makes use of the negative regulator LM2990...
This circuit was found in a 90s Radio Electronics. MOSFETs must have excellent heat sinks and heat and...
An oscillator slightly different from the previous one also appeared in Radio Electronics magazine in...