The invention relates to a method for improving the performance of nickel electrodes in alkali chloride electrolysis by adding water-soluble platinum compounds to the catolyte. The handle portion being defined by two opposite side walls of the container and communicating, via a duct defined by the side walls, with an opening formed in one of the side walls. This sheet has a layer containing a light-diffusing material or a light-absorbing material on the rise surfaces. By doing so, when a transmission section is turned into an open position or a closed position, the abutment projections and the key portion are collided with each other, thereby generating a click sound. In a third stage, the scaled compensated signal is then injected again into the same DC estimation mechanism, which was previously used for DC compensation in the first stage, for further DC offset estimation and compensation.