This rectangular signal generator was found in an Electronics World of 1966. The transistors are from that time and modern equivalents can be tested.
This circuit for audio signals was found in the March 1990 Radio Electronics magazine. The circuit...
In the figure we have the way to implement a sinusoidal oscillator with the 4093 IC. The component...
Equivalent transistors, like the BC548 and BC558 pair can be used in this circuit that we find in an...