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Electric vehicle wireless power transfer or wireless charging is generally divided into three categories: stationary charging when the vehicle is parked for an extended period of time; dynamic charging when the vehicle is driven on roads or highways; and quasi-dynamic or semi-dynamic charging, when the vehicle moves at low speeds between stops ...
Typically smaller than 0.01 cm 2 /(V⋅s); depends on electric field; increases with increasing temperature Starting with Ohm's law and using the definition of conductivity , it is possible to derive the following common expression for current as a function of carrier mobility μ and applied electric field E :
Left: modern inductive power transfer, an electric toothbrush charger. A coil in the stand produces a magnetic field, inducing an alternating current in a coil in the toothbrush, which is rectified to charge the batteries. Right: a light bulb powered wirelessly by induction, in 1910
The motion of electric charges is an electric current and produces a magnetic field. In most applications, Coulomb's law determines the force acting on an electric charge. Electric potential is the work done to move an electric charge from one point to another within an electric field, typically measured in volts.
Electric charge is a conserved property: the net charge of an isolated system, the quantity of positive charge minus the amount of negative charge, cannot change. Electric charge is carried by subatomic particles. In ordinary matter, negative charge is carried by electrons, and positive charge is carried by the protons in the nuclei of atoms ...
There are two recognized types of charge carriers in semiconductors.One is electrons, which carry a negative electric charge.In addition, it is convenient to treat the traveling vacancies in the valence band electron population as a second type of charge carrier, which carry a positive charge equal in magnitude to that of an electron.
The diffusion coefficient for a charge carrier is related to its mobility by the Einstein relation. For a classical system (e.g. Boltzmann gas), it reads: = where: k B is the Boltzmann constant; T is the absolute temperature; e is the electric charge of an electron
Examples of transport processes include heat conduction (energy transfer), fluid flow (momentum transfer), molecular diffusion (mass transfer), radiation and electric charge transfer in semiconductors.