A method of studying electrode potentials and polarization
Helmut Höller · Scientific Papers of the Bureau of Standards · 1925
A resistance-coupled electron-tube amplifier was used to operate an oscillo- graph for observing and recording the variations in potential of several elec- trodes without requiring any current from the electrode under investigation.By superposing alternating current upon the electrode it was possible with the use of a separately excited wattmeter to measure the potential due to re- sistance, and compute the boundary resistance at the electrode.The paper is limited to a description of the method and illustrations of its use in the case of some typical electrodes, including both smooth and platinized platinum, carbon, lead, and copper in sulphuric acid, and copper in a copper sulphate solution.CONTENTS Page potentiometer gives an average value of a variable^quantity over an interval of time, depending upon the speed of the commutator, and this average value must obviously be somewhat lower than the polari- zation at the instant of interruption of the current.The oscillograph was used by LeBlanc^and Eeichenstein « for the study of polarization, but the objection to its use is obvious for the reason that considerable current is required to operate this de- vice, and, as used, the current was necessarily supplied by the cell under investigation.The difference in potential across the cell was doubtless affected by the delivery of the current.However, since the polarization, after the interruption of the current is a rapidly " Lewis and Randall, " Thermodynamics," p. 386 ; 1923.