At 07:39 28.09.01, Scott Gravenhorst wrote: >Very cute! I assume I can make this linear by >replacing the expo current sink with the opamp >and darlington tpye linear sink? Dang is that >simple! Thanks René! Right, all you need is a current sink that sinks the current to GND (or -Ub). Cheers, René -- uzs159 at uni-bonn.de http://www.uni-bonn.de/~uzs159