Found in a 90's EDN, this circuit controls both the speed and the direction of rotation of a stepper motor. Relays can be replaced by MOSFETs, with circuit adaptations.
This simple metronome, from 1985 documentation uses only transistors and has two settings. For...
This circuit is suitable for modulating AM transmitters. The circuit is from a 1977 radio amateur...
This flasher was found in an old Hands On, but uses common components. The optocoupler can be...