The circuit shown in the figure below is from the 1993 Linear Technology Applications. The operational ones used are uncommon and the use of equivalents can be analyzed.
This voltage-controlled oscillator was found in a 1965 Electronic Design. Transistors are from the...
Found in an American publication from the 50's, this circuit uses input and output coup-ling...
This circuit is from a magazine 73 for radio amateurs of the 90s. The circuit generates the high...