Amperostatic Coulometry or constant-current coulometry:

The current, in a coulometric titration is carefully maintained at a constant and accurately known level by means of an amperostat, (It=Q) required to reach an end point. Q is proportional to the quantity of the analyte involved in the electrolysis. The essential requirement is 100% current efficiency to a single change in the analyte.

In these titrations, the titrant is generated at one of the electrodes. The reaction may take place directly on the same electrode or on the other electrode. To remove the interferences, when may occur, the reagent is separated from the solution by the use of sinter glass.

The reagent can be generated externally also, which removes the interferences. Such a cell has mainly been used to generate H⁺/OH^- ions.