
Theory
13
The permittivity of free space (vacuum permittivity) also called electric constant
0
is the ratio D/E
in free space. It also appears in the Coulomb force constant 1/4
πε
o
.
D= electric displacement field
E= electric field
0
= vacuum permittivity
C
0
= speed of light
0
= vacuum permeability
The constants c
0
and
0
also called “physical constants” are defined SI units to have exact
numerical values.
s
m
c
8
10
99792458
.
2
0
=
Am
Vs
7
0
10
4
−
=
m
pF
m
F
s
m
Am
Vs
c
...
85
.
8
10
....
8541878
.
8
10
99792458
.
2
10
4
1
1
12
2
8
7
2
0
0
0
=
=
=
=
−
−
C
oil
= Measured capacity of the test cell with liquid insulating dielectric
C
air
= Measured capacity of the test cell with air as dielectric (Tettex Oil Test Cell 2903 approx. 60
pF
20%)
0
= Vacuum permittivity
r oil
= Relative permittivity of the liquid insulating
r air
= Relative permittivity of air (
1)
A= Surface of test cell (Tettex Test Cell 2903 approx. 0.0134 m
2
)
l= Distance between surface ( Tettex Oil Test Cell 2903 approx. 0.002 m)
Summary of Contents for 2830
Page 1: ...2830 2831 Precision Liquid and Solid Dielectric Analyzer User Manual 4843477 M Version 3 0 ...
Page 7: ...Introduction VII 17 Conformity 113 18 Notes 114 ...
Page 8: ...VIII Introduction ...
Page 121: ...Conformity 113 17 Conformity ...
Page 122: ...114 Notes 18 Notes ...
Page 123: ...Notes 115 ...