This circuit, with a 12 V input, was found in a Popular Electronics from the 1990s. Information is given about the ferrite-wrapped transformer. The transistor must be mounted on a heatsink.
We found this circuit in the Linear Applications Handbook by National Semiconductor. The circuit uses...
This circuit was found in an American documentation from 1977. The circuit can be implemented with modern...
In the original circuit a 40431 quadrac is used, but this is not a common component today....