The zener (or a TL431) trimmed by the left pot creates the Vref, which represents Imax. The right pot sets a the current to sink as 1V/1A. The function of left (trim) and right (set) pots are interchangeable.
Q: How do I set the N Chanel MOSFET parameters from the info found in a datasheet?
R: tweak until it fit
