

The capacitance (or ideal capacitor) of videomodels represents in 3D the behavior of the linear circuit theory capacitance.
The circuit theory allows to model each real component by a set of basic ideal components
(or elements ) interconnected.
A two terminals component is called dipole . It imposes a relationship linking the voltage between its terminals and the current flowing therethrough. In the important case of linear circuits, the dipole elements are only five:
The capacitance is characterized at all times by law : $$ I = C \cdot \frac{dU}{dt} $$ This element is involved in the modeling of many real components, especially capacitor which is the real component whose behavior is supposed to match the best than the capacitance. Very often C coefficient, also called capacitance is simply considered as a constant independent of U and I . We say then that the capacitance is linear. The capacitance symbol (like capacitor) consists of two parallel segments (see figure below). The capacitance is here represented in 3D by cyan parallel bars or plates, joined by dotted lines symbolizing the existence of an electric field between the plates. Note that the electric field is expressed in volts per meter and its representation is only "relative" on videomodels because there are no indications of distances on a circuit diagram. If we look for the capacitor on the videomodel below, we can see the permanent link between the current and the voltage variation.


What is : 



Observe on the running videomodel ( Run ) that at any time, the current is proportional to the voltage variation across the capacitor. If the current is higher, the tension grows faster. If the voltage decreases, the current is negative. 

ReferencesCapacitor. Wikipedia.http://en.wikipedia.org/wiki/Capacitor 

See also : 