This circuit was found in documentation from the 80s. It is based on unijunction transistors not very common today being synchronized by the 60 Hz power grid.
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...