This cassette player motor speed control was found in the January 1991 issue of Radio Electronics magazine. The circuit is for voltages from 9 to 12 V.
This circuit is from an English publication from 1976 but can be easily assembled with BC548...
This configuration, found in many publications, is from an American book from 1981. The power...
The purpose of this circuit is to ensure that an auxiliary 12 V battery continues to supply power...