This simple step of low power audio is from a 1975 documentation. The transistor can be a BC548, and the transformer of the type found in small transistor radios and recorders of the time.
This simple experimental circuit using only transistor produces a tone given by C1 and C2. Tone is...
This circuit, which can be used as a shield, was found in American documentation from the 1970s....
I This well-crafted circuit was found in an American documentation from 1975. The components are...