We found this circuit in an old American publication from the 1980s. Transistors can be general-purpose types like the BC548, and the tuning frequency is given by the L and C components.
This special effect circuit with LEDs using the 4017 was obtained in a 1982 publication. LEDs are...
Found in a 1967 Electronics World, this circuit uses unusual components today. The transformer has a high...
In the figure we have the basic configuration of a rectangular oscillator using an operational amplifier...