In general, there is a relation between the amount of a substancelike quantity stored in a system, and the value of the potential of this system.

For example, if a fluid is stored in a (pressure) vessel, the fluid has a certain pressure. If more fluid is in the container, the pressure is larger. The concrete pressure – volume relation is called the pV-characteristic.

In general, we have a phi – X characteristic (where phi is the proper potential, and X is the quantity stored). This we call the capacitive characteristic of the system.

The relation can be expressed graphically, formally with an equation interpolating the measured function phi(X), or with the help of the tension factor alpha_X (first equation), or in terms of capacitance C (second equation).

If C = const:

    ∆X = C·∆phi

capacitance content relation, capacitance,

kapazitive Characteristik