This regulator can use BD'136 as the main transistor and as a reference next to a BC548 zener. The circuit provides a voltage of 9V from 12 to power devices that use batteries.
The integrated circuit used is equivalent to the 555 and the transistor can be the BC558. R1 and...
This circuit was found in an old American documentation. The transformer is of the type found in...
We find this circuit in a 1980s documentation. The integrated ones are of the time and their...