Found in a 90s Silicon Chip documentation, this circuit provides a current of 3 A and the voltages range from 0 to 20 V. The integrated circuit and the transistor must have heat sinks.
This circuit is from an English magazine of 1977. The circuit is still current, just using BC547...
The adjustment of the maximum load voltage is made in the trimpot. The circuit is from 1994...
In the figure we have the conventional configuration of a differential amplifier with the...