Hioki DSM-8542, Instruction Manual, Page: 74 / 140

64
Volume resistance and surface resistance measured and multiplied by an electrode
constant are called volume resistivity (
ρ
v
) and surface resistivity (
ρ
s
), respectively.
Π ·
D1
2
Measured value
Volume resistivity
ρ
v
＝
×
4t 10
where
ρ
v
: volume resistivity in [
Ω
·cm]
Π
: circle ratio = 3.14
D : diameter of main electrode in [mm]
ｔ
: Sample thickness in [mm]
Π ·
(
D2+D1)
Surface resistivity
ρ
s
＝
× Measured value
D2-D1
where
ρ
s
: surface resistivity in [
Ω
]
Π
: circle ratio = 3.14
D : diameter of main electrode in [mm]
ｔ
: inside diameter of pair electrode (Electrode B) in [mm]
(2) Electrode constant setting
Measure volume resistivity and surface resistivity by setting measuring modes
for volume resistivity measurement and surface resistivity measurement
respectively referring to 5.1.2 “Setting measuring mode.”
The meter is capable of automatically performing calculations of volume
resistivity and surface resistivity mentioned in 1). For this purpose, set in
advance constants of electrodes to be used in measurement as follows.
The following three electrode constants are set:
D1 (IN DIAMETER): Set diameter of the main electrode (A) in increments of mm.
D2 (OUT DIAMETER): Set inside diameter of the pair electrode (B) in
increments of mm.
t (THICKNESS): Set thickness of the sample in increments of mm.
Set the desired electrode constants on the screen illustrated in Fig. 6.4.
On the measurement screen, measured volume resistivity and surface resistivity
are indicated by “Rv” and “Rs” respectively.
Press the [ELEC] (SET ELECTRODE SIZE) key on the measurement screen.
The screen will change to a screen for setting electrode constants to be used in
measurement of volume and surface resistivities. (See Fig. 6.4)