This circuit was found in an Elektor from the 90s. It is a circuit that generates different types of sound effects. The components are still common today.
Texas Instruments ESD122 Electrostatic Discharge Diodes (ESD) can be ordered from Mouser...
This circuit was suggested in a 1976 documentation. We can use the pair BD135 and BD136 on the...
This interesting circuit found in an Elektor from the 90s controls loads in four quadrants of the driving...