
Capa model The capacitance of a capacitor (or condenser) is characterized with the
permittivity ε of the dielectric medium of thickness d which is between two electrodes of surface S.
Parallel connections for power applicationsThe resulting capacitance is the sum of the individual capacitances.Series connections for high voltage applicationsThe resulting inverse capacitance is the sum of the individual inverse capacitances. Capacitor technologies
The force is oriented along the direction separating the two charges. The α factor depends on the unit system. In MKSA the charge is given in Coulomb [C], the distance in meter [m] and the force in Newton [N]. With Gauss law, it's given by Electric fieldFinally the force is given by
Considering that the charge q_{2} is placed in the electric field created by q_{1}, this field is given by The vector electric field has its foot on q_{1} when this latter is positive. Electric potentialThe force on charge q_{2} is equal to:
Charge densityThe charge volumetric density is given the number of charge in an infinitesimal volume pondered by this volume: It's more convenient to use the « polarization » P, instead of taking into account all the charges in a material. In the Maxwell macroscopic model only the free charges (those which are not involved in a dipole) are considered in the charge density. Historically Maxwell has written first his « microscopic » equations before the wellknown « macroscopic » ones. Electric polarization
