perform a coulometry in an automatic way. Coulometers can be used to determine electric quantities in the direct current circuit, namely the total charge or a constant current. These devices invented by Michael Faraday were used frequently in the 19th century and in the first half of the 20th century. In the past, the coulometers of that type were named voltameters. See also Electrochemical cell Electrochemical equivalent Electrochemistry Electrolysis Electrolytic cell Equivalent (chemistry) Equivalent weight Faraday's laws of electrolysis Stoichiometry Sources Practical Electricity by W. E. Ayrton and T. Mather, published by Cassell and Company, London, 1911, pp 12–26 References Measuring instruments Electroanalytical chemistry devices