A completely automatic capillary electrometer controlled by an on‐line digital minicomputer is described. This instrument is based on the maximum bubble pressure principle and is not subject to the systematic errors of the classical Lippmann electrometer in the presence of dilute solutions of weakly adsorbed electrolytes. Details of the interface hardware and the necessary software are given. The instrument is capable of producing very high quality electrocapillary data comparable to that which can be obtained with a capacitance bridge in the case of simple salt solutions and superior to bridge data in the case of the electrosorption of organic compounds which exhibit very high capacitance desorption peaks.