This precision speed control was obtained in an Electronic Design from the 90's. The output final stage power transistors must be in accordance with the motor power.
This circuit is from 2001 documentation, serving to multiplex stereo signals for FM transmitters. The...
This circuit reverses the signal if both positive and negative. We found it in an American...
Found in a publication by Gernsback from 1960, this circuit makes use of germanium transistors of the time....