Found in an American publication from 1968, this circuit can be made based on a TIP42 that must be mounted on a heat sink. The transformer is 25 V with a current of 3 to 4 A.
This circuit mimics the sound of a siren when we turn the axis of the small DC motor. The...
This sophisticated RPM counter circuit with discrete integrated circuits was obtained in a 1993...
This circuit uses complementary transistors and was found in Mullard's transistor application...