Found in American documentation from the 90s, this circuit triggers a buzzer with a Sonalert-type oscillator when the temperature of the sensor reaches a certain value set in R2.
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...