Permittivity
What it is
Permittivity is the quality of a material that allows it to store an electrical charge. A given
amount of material with high permittivity can store more charge than a material
with lower permittivity. Dielectrics are insulators with high permittivity.
Permittivity is the time-space-mass domain expression of velocity^-2. When
working with electrical problems, consider that the reciprocal of permittivity
occupies the same position on the property chart as velocity^2.
History
James Maxwell (1831-1879) formulated the concepts of permittivity and
permeability to serve as constants in his equations which described most
electro-magnetic behavior. Amazingly, using data from experiments on capacitors
and coils, he was able to predict the existence of radio waves including their
velocity. Maxwell's books on electro-magnetics and "Matter and Motion"
are powerful reading and provide a much clearer view of reality than most modern
books.
Common equations
permittivity = electric field strength / dielectric
displacement
speed of light^2 * permeability * permittivity = 1
capacitance = permittivity * area / length
permittivity = refraction index^2
Units
farads/meter
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