This is a high quality power supply with a continuously variable stabilised output adjustable at any value between 0 and 30VDC.
The circuit also incorporates an electronic output current limiter that effectively controls the output current from a few milliamperes (2mA) to the maximum output of three amperes that the circuit can deliver. This feature makes this power supply indispensable in the experimenters laboratory as it is possible to limit the current to the typical maximum that a circuit under test may require, and power it up then, without any fear that it may be damaged if something goes wrong.
There is also a visual indication that the current limiter is in operation so that you can see at a glance that your circuit is exceeding or not its preset limits. You can find more files for this PS in my another Link (DropBox).