Agilent Technologies 4339B - Page 215

4339B
Resistivity
Resistivity
V
olume
Resistivity
In
general,
volume resistivity
is dened
as the
resistance per
unit volume
.

v
=
Ar
ea
t
R
v
2
1
10
where
,

v
V
olume
resistivity
[-cm]
Area
Eective
area
[mm
2
]
t
Thickness
of
the
sample
[mm]
R
v
Measured
volume
resistance
[]
When
the
16008B
Resistivity
Cell
is
used,
the above
equation becomes:

v
=

2

D
1
+
B
(
D
2
0
D
1
)
2

2
4
t
2
R
v
2
1
10
Where
,
D
1
Main
electrode
diameter
[mm]
D
2
Guard
electrode
diameter
[mm]
B
Eective
area
coecient
B
is
the
fraction
of
the
gap
width to
be added
to
the
diameter
of
the
circular
electrodes
or
to
the
dimensions
of
rectangular
or
cylindrical
electrodes
.
The
value is
usually
specied
by
the
standard
that you
use
.
(F
or
example:
1
for
ASTM
D
257;
0
for
JIS
K6911).
Figure 7-1. Volume Resistivity
Measurement Basics 7-3