12 Facts About Current density

In electromagnetism, current density is the amount of charge per unit time that flows through a unit area of a chosen cross section.

The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the positive charges at this point.

The only component of current density passing normal to the area is the cosine component.

Current density is important to the design of electrical and electronic systems.

Circuit performance depends strongly upon the designed current level, and the current density then is determined by the dimensions of the conducting elements.

The current density must be kept sufficiently low to prevent the conductor from melting or burning up, the insulating material failing, or the desired electrical properties changing.

Analysis and observation of current density is used to probe the physics underlying the nature of solids, including not only metals, but semiconductors and insulators.

Current density is an important parameter in Ampere's circuital law, which relates current density to magnetic field.

Common approximation to the current density assumes the current simply is proportional to the electric field, as expressed by:.

Above conductivity and its associated current density reflect the fundamental mechanisms underlying charge transport in the medium, both in time and over distance.

In dielectric materials, there is a current density corresponding to the net movement of electric dipole moments per unit volume, i e the polarization P:.

In gas discharge lamps, such as flashlamps, current density plays an important role in the output spectrum produced.