External generation apparatus:

The cell consists of two electrodes of platinum gauze separated through a sintered glass disk.  The anode compartment produces H⁺ ions, when the cathode compartment generates OH^- ions.  The apparatus is so arranged which flow of electrolyte continues even after the current is discontinued, therefore flushing the residual reagent within the titration vessel.

This category of external generation apparatus has also been used for the generation of other reagents like as iodine through the oxidation of iodide at the anode, generation of titanous ions etc.  The external generation methods has been successfully applied to titrations including hydroxyl, hydrogen, iodine etc. and for the generation of reagents, that are quite unstable, like as chlorine, bromine, titanium (III) ions, many more.  Therefore, coulometric titrations are more advantageous than conventional volumetric titrations.

It should be remember in which external generation of reagents is probable if only the titrant be produced with 100 percent current effectiveness.