What is dielectric?

  • (noun): A material such as glass or porcelain with negligible electrical or thermal conductivity.
    Synonyms: insulator, nonconductor


A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material as they do in a conductor, but only slightly shift from their average equilibrium positions causing dielectric polarization. Because of dielectric polarization, positive charges are displaced toward the field and negative charges shift in the opposite direction. This creates an internal electric field which reduces the overall field within the dielectric itself. If a dielectric is composed of weakly bonded molecules, those molecules not only become polarized, but also reorient so that their symmetry axis aligns to the field.

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Some articles on dielectric:

Some Practical Dielectrics
... Dielectric materials can be solids, liquids, or gases ... In addition, a high vacuum can also be a useful, lossless dielectric even though its relative dielectric constant is only unity ... Solid dielectrics are perhaps the most commonly used dielectrics in electrical engineering, and many solids are very good insulators ...
Tantalum Capacitor - Construction - Dielectric
... The dielectric is then formed over all the tantalum particle surfaces by the electrochemical process of anodization ... The total dielectric thickness is determined by the final voltage applied during the forming process ... dielectric thickness) has been reached it then holds this voltage and the current decays to close to zero to provide a uniform thickness throughout ...
Capacitance Probe - Applications
... of water in the total volume of soil most heavily influences the dielectric permittivity of the soil because the dielectric of water (80) is much greater than the ... will measure a change in capacitance due to the change in dielectric permittivity that can be directly correlated with a change in water content ... Cure monitoring of Composite materials Dielectric or Capacitance Sensors are used to measure the electrical response of thermoset resins and matrices of composite ...
Applications Of Capacitors - Sensing - Changing The Dielectric
... The effects of varying the characteristics of the dielectric can also be used for sensing and measurement ... Capacitors with an exposed and porous dielectric can be used to measure humidity in air ...
... Magnetocapacitance is a property of some dielectric or insulating materials and/or metal-insulator-metal heterostructures that exhibit a change in the ... Magnetocapacitance can be an intrinsic property of some dielectric materials, such as multiferroic compounds like BiMnO3, or can be a manifest of properties extrinsic to the dielectric but present in capacitance ...