This circuit of the 80s makes use of an operational one of the time. It can be designed with modern operationals and must use a symmetrical power supply.
In the figure we have the typical configuration of a Hartley oscillator. This circuit generates...
Found in an Electronics Now from the 90s this mixer has several inputs. The integrated circuit can...
This useful power supply was found in an 1985 Italian publication, but can still be assembled...