Current step, electrical double layer capacitance

For conducting and completely polarizable surfaces, the capacitance can be measured directly with great precision. In the most simple capacitance measurement, called chronoamperome-try, a potential step AU is applied to an electrode (Fig. 5.10). A current flows due to charging of the diffuse electrical double layer. The current flows until the capacitance is fully charged. By measuring the current as a function of time and integrating the curve with respect to time we get the charge Q. The total capacitance C is easily obtained from C = CA A = Q/AU. 

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