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 instrument, which has built-in an ac current amplifier, is particularly suited for detecting small current fluctuations in the frequency range betweeen 0. 1 and 2000 Hz. The noise in the dc control voltage is of the order of 2. 5 multiplied by 10** minus **8 V/ ROOT Hz, and the instability of the ac amplifier corresponds to a signal of 3 multiplied by 10** minus **1**1 A/ ROOT Hz. The performance characteristics of the instrument are fully described as well as its use in impedance measurements by means of a swept frequency signal. The instrument can also be used as a galvanostat.