What is dielectric strength?
Regarding the ability to conduct electrical current, we can classify various materials into conductors, insulators and semiconductors.
You conductors present a great quantity of electronsweakly linked to coresatomic, favoring the conduction of electric current. You semiconductors, in turn, need a stimulusexternal (like high temperatures) so that its electrons are excited and can be conducted. Already the materials insulators (also known as dielectrics) have their electrons tightly linked to atomic nuclei, making the formation of electric currents in these materials.
However, there is a maximum value of fieldelectric in which insulating materials start to behave as conductors, thus allowing the formation of electrical currents. This value is specific for each material, it depends on your thickness and receives the name of rigiditydielectric.
Dielectric strength of some materials
The table below shows the maximum electric field values for the dielectric strength of some materials to occur:
Material |
Dielectric strength (V/m) |
Air |
3.106 |
Rubber |
12.106 |
Paper |
16.106 |
|
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8.106 |
Teflon |
80.106 |
The table indicates that, for air, an electrical voltage of 3millionsinvolts per meter so that it becomes a conductor. When this happens, the electrons have energyenough to move between the molecules in the middle.
Breakage of dielectric strength of air
the phenomenon of breakdielectric from the air is responsible by the formation of dischargeselectricatmospheric, popularly known as rays.
O atmospheric air is a means insulating which has a dielectric strength of 3.106 V/m. When the atmospheric electric field between the clouds and the ground reaches close values, the air molecules are ionized, which makes the air a medium. conductor.
through the It is madeJoule, the electric current formed in the air causes a large heating, who is responsible for dilation of the gaseous medium, producing the wavessonorous known as thunder. More molecules are stripped of their electrons and eventually these free electrons are captured by other ionized molecules. It is in this process that the issueinlight known as lightning.
By Rafael Hellerbrock
Graduated in Physics
Would you like to reference this text in a school or academic work? Look:
HELERBROCK, Rafael. "What is dielectric strength?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/fisica/o-que-e-rigidez-dieletrica.htm. Accessed on June 27, 2021.
