Principles of Voltammetry Potential control and the Nernst Equation A key feature in understanding Volta metric methods is the relationship between the potential applied to an electrode and the concentration of redox species at the electrode surface. Consider and electrode at equilibrium with the solution in which it is immersed. The electrode will exhibit a potential, invariant with time and related thermodynamically to the composition of the solution. Assume that the solution contains species o witch is capable of being reduced to R at the electrode by the following reversible electrochemical reaction: