SOLUTION IR DROP

"The ir drop in the electrolyte solution of a three-electrode cell between the working and the reference electrodes. This ir drop (which is expressed as a potential) is always included in the measured potential of the working electrode. Therefore, it is important to minimize this error, and to place the reference electrode as close as possible to the working electrode (see Luggin tip). It is also called ""ohmic overpotential (or polarization)"" or ""resistance overpotential (or polarization)."" One can correct for the ir drop to obtain the real electrode potential, or in some cases one can compensate for the ir drop during potential control. During the measurement of an electromotive force (potential measurement without any current flowing), the ir drop is always zero, and the position of the reference electrode is immaterial. See also ohmic loss. "