This circuit is from an 80's publication. It makes use of small 6 V x 50 mA incandescent lamps. The diodes can be general purpose or even 1N4002. The transformer is 6.3 V with 100 mA or more current.
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...