The Potentiostat

Gain-Phase with 90 % Ir CompensationA [dB]r+ Rs+RdlAoRe l + r + Rs + Rdlr + Rdl3r − 0 .9 r + Rdl11 + pτ1 + pτ eο1+ pτ′′1 + pτ′′1 + pτ′fer3r − 0 .9 rfo fc ' fc '' ftΦ 0Compromising DC accuracy against ACstability one can achieve somesatisfactory results by applying partialpositive “Ir” compensating feedback. Thelimit in the illustrated figure is set to 90%Ir compensation, the Ir drop is canceledout to a 10% error term, but the criticalpoint of intersect N has been moved to anew position where the phase angle ismuch safer (close to 90 0 in this particularcase) and the control system stability issecurely preserved.This approach of partial Ir compensationis commonly adapted in theelectrochemical experimenter practicesince the inferior DC accuracy is greatlyoffset by the risk of utilizing a potentiallyuseless, unstable and destructive system.