A low-noise potentiostat for the study of small amplitude signals in electrochemistry

Abstract

A low-noise potentiostat, developed and built at NBS, is described. The ins trum ent, whi ch has built-in an ac current amplifier, is particularly s uited for detec ting small curre nt flu ctua ti ons in the fr eque ncy range be twee n 0.1 and 2000 Hz. Th e noise in the dc co ntrol voltage is of the orde r of 2.5 X 10-' V I VHz, and the ins tability of the ac amplifier corres ponds to a signal of 3 X 10-" A/ vHz. Th e performance characteris tics of the ins trum ent are fully desc rib ed as well as its use in impe dance meas ure ments by means of a swept fr equency signaL The instrument can also be us ed as a galvanosta L