This circuit, with 1 A output, was found in a 1975 documentation. The transistors admit equivalents and the transformer has windings according to the voltages being worked.
The figure shows how to use an LM3914 with a variable range moving point. The circuit has an...
This circuit was found in a 90s Popular Electronics. It uses a varicap that admits equivalents. The...
This circuit is from an Electronics Now from 1998 and can be easily assembled with other JFET...