dielectric

dielectric
/duy'i lek"trik/, Elect.
n.
1. a nonconducting substance; insulator.
2. a substance in which an electric field can be maintained with a minimum loss of power.
adj.
3. of or pertaining to a dielectric substance.
[1830-40; DI-3 + ELECTRIC]

* * *

Insulating material or a very poor conductor of electric current.

Dielectrics have no loosely bound electrons, and so no current flows through them. When they are placed in an electric field, the positive and negative charges within the dielectric are displaced minutely in opposite directions, which reduces the electric field within the dielectric. Examples of dielectrics include glass, plastics, and ceramics.

* * *

      insulating material or a very poor conductor of electric current. When dielectrics are placed in an electric field, practically no current flows in them because, unlike metals, they have no loosely bound, or free, electrons that may drift through the material. Instead, electric polarization occurs. The positive charges within the dielectric are displaced minutely in the direction of the electric field, and the negative charges are displaced minutely in the direction opposite to the electric field. This slight separation of charge, or polarization, reduces the electric field within the dielectric.

      The presence of dielectric material affects other electrical phenomena. The force between two electric charges in a dielectric medium is less than it would be in a vacuum, while the quantity of energy stored in an electric field per unit volume of a dielectric medium is greater. The capacitance of a capacitor (capacitor dielectric and piezoelectric ceramics) filled with a dielectric is greater than it would be in a vacuum. The effects of the dielectric on electrical phenomena are described on a large, or macroscopic scale by employing such concepts as dielectric constant, permittivity (qq.v.), and polarization (see electric polarization).

* * *


Universalium. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • dielectric — DIELÉCTRIC, Ă, dielectrici, ce, adj., s.n. 1. adj. Care izolează din punct de vedere electric; izolator. ♢ Constantă dielectrică = raportul dintre capacitatea unui condensator electric care conţine între armături o substanţă izolatoare şi… …   Dicționar Român

  • dielectric — [dī΄i lek′trik] n. [ DI(A) + ELECTRIC: so called because it permits the passage of the lines of force of an electrostatic field but does not conduct the current] a material, as rubber, glass, etc., or a medium, as a vacuum, gas, etc., that does… …   English World dictionary

  • Dielectric — Di e*lec tric, n. [Pref. dia + electric.] (Elec.) Any substance or medium that transmits the electric force by a process different from conduction, as in the phenomena of induction; a nonconductor, separating a body electrified by induction, from …   The Collaborative International Dictionary of English

  • dielectric — Physics ► ADJECTIVE ▪ non conducting of electricity; insulating. ► NOUN ▪ an insulator …   English terms dictionary

  • Dielectric — 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 in a conductor, but only slightly shift from their …   Wikipedia

  • dielectric — noun Etymology: dia + electric Date: 1837 a nonconductor of direct electric current • dielectric adjective …   New Collegiate Dictionary

  • dielectric — di·elec·tric .dī i lek trik n a nonconductor of direct electric current dielectric adj * * * di·elec·tric (di″ə lekґtrik) 1. transmitting electric effects by induction, but not by conduction. 2. an insulating substance that transmits… …   Medical dictionary

  • dielectric — di·e·lec·tric || ‚daɪɪ lektrɪk n. insulator, material that does not conduct electricity adj. of or pertaining to a dielectric substance, of or pertaining to a material that does not conduct electricity …   English contemporary dictionary

  • dielectric — di•e•lec•tric [[t]ˌdaɪ ɪˈlɛk trɪk[/t]] n. 1) elm a nonconductor of electricity; insulator 2) elm a substance in which an electric field can be maintained with a minimum loss of power 3) elm of or pertaining to a dielectric substance • Etymology:… …   From formal English to slang

  • dielectric — /daɪəˈlɛktrɪk/ (say duyuh lektrik) Electricity –adjective 1. non conducting. 2. conveying electric effects otherwise than by conduction, as a medium through which electricity acts in the process of induction. –noun 3. a dielectric substance;… …  

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”