Experience has shown us that a high density of matrix points around those areas with high concentration flux, produces more accurate results. Therefore our matrix should concentrate its points around these regions. The following maps show how the concentration of R is predicted to change around the electrode after a potential step. Short Times Long Times Notice how the diffusion toward the electrode changes from linear to hemispherical. Flux Lines And Concentration Contours Concentration contours give a snapshot of how the concentration of R is distributed around the electrode.
Flux lines show the direction of movement towards the electrode.
The diagram below shows how the concentration of R is both distributed and moving around an electrode shortly after a potential step. The current measured by a microelectrode changes when it is brought close to a solid surface. By using an insulating surface, the diffusion of the reactant R to the probe is partially blocked and therefore the current measured is less than expected. This is termed hindered diffusion or negative feedback. Where a conducting surface is used and held at a potential so that it turns the product O back to R , a higher current is measured.