This is a simple constant current sink. It can be used to simulate a DC load. Need for it had arisen as I acquired a couple of cheap DC-DC converters and needed a way to test them, to see if they really put out the amount of current as advertised. Some of the specs: 20V, 5A, 20W continuous dissipation, reverse polarity protection, 4mm banana-type binding posts for easy multimeter and load connection, current calibration with a 25-turn trimmer, 10-turn wire-wound potentiometer to set the current.
The very latest updates and bugfixes / errata can be found on my github page. So far I have only detected minor nuisances that are easily fixed. Most notably is the voltage regulator, which needs a minimum current for stable operation. This can be achieved by either letting the power LED draw more current, or by putting a small 1k resistor across the regulators output. Note to self: in case of doubt, read the datasheet ;-) [Link]