Volume Resistivity:
V
throu
centimeters. Likewise, the electrical re
insu
Volu
opposit
the sam
calculations:
or
Wher
Surface Resis
the surface of an
along the surface of
measurement
and diameter) of
Surface resistivity (
surface of the insulator s
perform
Wher
3.3
Resistivity nomographs
With test voltage and measured current (and sample thickness for volume
resistivity) known, resistivity can be approximated by using the appropriate
nomograph. Figure 3-2 shows the nomograph for surface resistivity and Figure
3-3 shows the nomograph for volume resistivity.
Surface Resistivity:
The surface resistivity nomograph (Figure 3-2) is made up
of three scales; voltage, resistivity and current. Perform the following steps to
determine resistivity:
1. Plot the test voltage value on the voltage scale.
2. Plot the measure current value on the current scale.
3. Draw a straight line connecting the plotted voltage and current values.
4. Read the surface resistivity value (in ohms) from where the drawn line inter-
sects the resistivity scale.
An example is shown in the graph. The dashed line connects a test voltage of
200V to a measured current of 3
×
10
-10
amps (0.3nA). The dashed line intersects
the resistivity scale at just under 4
×
10
13
¾ (3.56
×
10
13
¾ by calculation).
Figure 3-2
Surface resistivity (
σ
) nomograph
14
15
Содержание 8009
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Страница 15: ...le is a two t are ew ew The n is 517 ILC 3 2 Operation 4 5 Blank page...
Страница 17: ...nced 7B oy the resistance rce as e to can be made record Figure 2 1 Model 8009 resistivity test fixture 6 7...
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