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In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field.When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor, because they have no loosely bound, or free, electrons that may drift through the material, but instead they ...
Electrical breakdown in an electric discharge showing the ribbon-like plasma filaments from a Tesla coil.. In electronics, electrical breakdown or dielectric breakdown is a process that occurs when an electrically insulating material (a dielectric), subjected to a high enough voltage, suddenly becomes a conductor and current flows through it.
The ESR is a derived quantity representing the loss due to both the dielectric's conduction electrons and the bound dipole relaxation phenomena mentioned above. In a dielectric, one of the conduction electrons or the dipole relaxation typically dominates loss in a particular dielectric and manufacturing method. For the case of the conduction ...
Because the dielectric relaxation time increases exponentially on cooling, the polarization caused by their alignment with the field gets "frozen-in". So when the field is removed and the material begins to warm the dipoles begin to "thaw" whereby losing their net alignment and thus the material become depolarized.
When a dielectric is placed in an external electric field, its molecules gain electric dipole moment and the dielectric is said to be polarized. Electric polarization of a given dielectric material sample is defined as the quotient of electric dipole moment (a vector quantity, expressed as coulombs*meters (C*m) in SI units) to volume (meters ...
A dielectric material that permanently retains an impressed electric field; the dual to a magnet. electric arc Discharge of electric current through an open space between conductors; may be produced intentionally as a source of intense light and heat, or may be a result of an electrical fault.
Dielectric films tend to exhibit greater dielectric strength than thicker samples of the same material. For instance, the dielectric strength of silicon dioxide films of thickness around 1 μm is about 0.5 GV/m. [3] However very thin layers (below, say, 100 nm) become partially conductive because of electron tunneling.
is the dielectric constant of the semiconductor. N A {\displaystyle N_{A}} and N D {\displaystyle N_{D}} are the net acceptor and net donor dopant concentrations respectively and q {\displaystyle q} is the charge of the electron.