This power supply was found in the September 1989 issue of Radio Electronics magazine. The 2N3055 must be equipped with a heat sink.
In this circuit, the transistors are NPN for general use and the phototransistors can be replaced by...
Using a standard multimeter, this circuit from a 73 magazine for radio amateurs provides an output...
We found this circuit in a Motorola manual. The circuit employs operationals that are uncommon today...