This power supply was found in the same 1990 special issue of Radio Electronics Experimenter magazine that describes an amplifier of up to 100 W per channel with the LM12.
In the figure we have the way to use a stepper motor as an encoder. Operational amplifiers can be of...
Placed inside the refrigerator, this circuit triggers an oscillator when the part is opened...
We found this circuit in an old documentation from the 70s, but it can be assembled with more...