dielectric
Sign in to savethumb|A polarised dielectric material (orange), between two metal plates
AI overview
A dielectric is a material that doesn't conduct electricity but can be polarized—meaning its electric charges shift slightly when placed in an electric field. Dielectrics are useful in devices like capacitors, where they're placed between metal plates to store electrical energy more effectively.
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Article
23 sectionsContents
- Terminology
- Electric susceptibility
- Dispersion and causality
- Dielectric polarisation
- Basic atomic model
- Dipolar polarisation
- Ionic polarisation
- In biological cells
- Dielectric dispersion
- Dielectric relaxation
- Debye relaxation
- Variants of the Debye equation
- Paraelectricity
- Tunability
- Applications
- Capacitors
- Dielectric resonator
- BST thin films
- Some practical dielectrics
- See also
- References
- Further reading
- External links
thumb|A polarised dielectric material (orange), between two metal plates
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 shift, only slightly, from their average equilibrium positions, causing dielectric polarisation. Because of dielectric polarisation, positive charges are displaced in the direction of the field and negative charges shift in the direction opposite to the field. This creates an internal electric field that reduces the overall field within the dielectric itself. If a dielectric is composed of weakly bonded molecules, those molecules not only become polarised, but also reorient so that their symmetry axes align to the field.