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The field strength at which break down occurs depends on the respective geometries of the dielectric (insulator) and the electrodes with which the electric field is applied, as well as the rate of increase of the applied electric field. Because dielectric materials usually contain minute defects, the practical dielectric strength will be a ...
Paschen's law is an equation that gives the breakdown voltage, that is, the voltage necessary to start a discharge or electric arc, between two electrodes in a gas as a function of pressure and gap length. [2] [3] It is named after Friedrich Paschen who discovered it empirically in 1889. [4]
The amount of heat generated by friction in the material is dependent on field strength, frequency, dipole strength, and free volume in the material. [1] Since the main driving force for dielectric heating is the interaction of the dipole of a molecule with the applied electrical field, RF welding can only be conducted on dipole molecules.
In a hydraulic analogy, passing current through a high-resistivity material is like pushing water through a pipe full of sand - while passing current through a low-resistivity material is like pushing water through an empty pipe. If the pipes are the same size and shape, the pipe full of sand has higher resistance to flow.
Electric resistance welding is widely used, for example, in manufacture of steel pipe and in assembly of bodies for automobiles. [2] The electric current can be supplied to electrodes that also apply clamping pressure, or may be induced by an external magnetic field.
The electrode and workpiece are connected to a suitable power supply. The power supply generates an electrical potential between the two parts. As the electrode approaches the workpiece, dielectric breakdown occurs in the fluid, forming a plasma channel, [16] [23] [24] [25] and a small spark jumps.
Effectiveness of cathodic protection (CP) systems on steel pipelines can be impaired by the use of solid film backed dielectric coatings such as polyethylene tapes, shrinkable pipeline sleeves, and factory applied single or multiple solid film coatings. This phenomenon occurs because of the high electrical resistivity of these film backings. [68]
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.