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Measuring Flat Sample
5.2 Measuring Flat Sample
Measuring insulation resistance of an object with no terminals installed requires something that can
function as terminals to be attached on the object.
The measurement method varies depending on the type of the terminal.
What function as terminals
It must be possible to switch the objects to be measured easily. Therefore, items with a structure that allows
them to function as terminals just by contacting the object is often used.
The terminals used for measurement must have proper contact with the object to be measured without any
loose connection.
For a solid insulation material, the method of bringing terminals (electrode) that have a specic pin shape
or those with smooth at surfaces, which can contact with smooth surfaces of objects to be measured
without any space between them, into close contact with the object to be measured is employed to measure
insulation resistance. (The shape and structure of the terminals varies depending on the shape and
characteristics of the object to be measured.)
Measurement using pin type terminals
Insulation resistance is classied into “volume resistance,” which is the current owing through the
measured object and “surface resistance,” which is the current owing along the surface of the
sample. To measure both of them together, use pin type terminals.
Example of pin creation
Make 2 holes (such as tapered holes) with a predened diameter at a certain interval on the at
sample. Apply material with relatively low insulation resistance, such as petroleum jelly, to the pins
and insert the pins into the holes to use them as terminals for measurement.
These pins are of a simple structure and provide relatively steady contacts, eliminating the need for
smoothing the surface of the sample to obtain a at surface.
Setting the instrument
Press the MODE key to switch the measurement mode to resistance value measurement mode,
and then perform measurement. (p. 39)
Measurement using an electrode for measuring surface resistance
The electrode for measuring surface resistance is used as terminals for measurement by pressing
it on the surface of the object to be measured. It provides an easy method to perform measurement
if the objects to be measured are relatively soft.
This electrode cannot exactly separate the volume resistance but can essentially measure the
surface resistance because it is generally lower.
In particular, this method is useful for objects to be measured that have been subjected to surface
anti-static treatment.
Setting the instrument
Press the MODE key to switch the measurement mode to sureface resistivity measurement mode,
and then preform measurement. (p. 39)
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