Found in American documentation from the 1980s, this circuit uses transistors from that time. It generates increasing and decreasing tones when we press and release the push button.
Here we show how two 4017s can be cascaded to count above 10. The circuits are driven by a square...
The circuit in the figure represents a typical application of a phototransistor exciting a relay...
This circuit, in fact, what it does is a reactivation of the batteries through a brief pulsating...