> https://www.electronicdesign.com/analog/whats-all-p-i-d-stuff-anyhow For all Bob Pease fans: there's a fabulous 9 volume ~1200 page scan of his columns here: https://archive.org/details/Bob_Pease_Lab_Notes The P-I-D article Ben mentions appears in volume 2, starting on page 167. /tvb