If the capacitance of a system is known as a function of the associated potential (or level), it is possiple to calculate the changes of content of the systems in terms of changes of potential.

capacitance

The diagram on the right (see Expressions) has the axes flipped relative to the graph on the left. In this form, the graph resembles the shape of a container, and the pink area equals the change of the contents of the container when the level changes.

If the capacitance is constant, the change of content can be calculated simply from

     delta_X = C_X*(phi_2 – phi_1)

Beziehung zwischen Kapazität und Inhalt