Using 4 operational amplifiers this circuit generates 4 different tones. The circuit is from an American documentation from the 90's. Operational amplifiers are tTL084.
This circuit can be used to produce the sound of bongo drums. Damping is adjusted by P1. The...
This interesting idea of a radio detector for a medium-wave radio is from a 1966 documentation. The critical...
This circuit was found in a 1965 General Electric publication. The circuit can be adapted to...