Suitable for operation with high impedance microphones, this circuit was found in American documentation from the 90s. The transistor can be any general-purpose type.
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...