Use the Harmonic Perturbation subnode to specify the voltage amplitude perturbation in the frequency domain. The harmonic perturbation is only applied when solving for a Frequency-Domain study type, which is typically used in AC Impedance studies.

The Harmonic Perturbation subnode can be added to the Electric Potential, Electrolyte Potential. The subnode is available from the context menu (right-click the parent node) or from the Physics toolbar in the Contextual group.

You may also specify harmonic perturbations to the Electrode Current Density, Electrolyte Current Density and Electrode Surface nodes.