Hioki Super megohm SM7110 - Page 90

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Measuring Flat Sample
(2) Measurement with the guard electrode
Because the current owing along the surface of the measured object ows out through the guard
electrode to the external power supply, the current owing across the object in the thickness
direction can be separately measured with accuracy.
A
(+)
(−)
Internal ammeter of the insulation meter
Current to be measured owing across the
object in the thickness direction
Current owing along the surface of the measured
object
Measured
object
Main electrode
Guard electrode
Counter electrode
Internal power
supply of the
insulation meter
Surface resistance measurement
(1) Measurement without the guard electrode (also applicable to measurement with use of Model
SME-8301)
Because the current owing through the measured object and the other current owing through the
base (insulator) are also measured unnecessarily, the current owing along the surface cannot be
separately measured.
A
(+)
(−)
Internal ammeter of the insulation meter
Current to be measured
owing along the surface
Current owing through the measured object
Measured
object
Main electrode
Counter electrode
Base (insulator such as a table)
Internal power
supply of the
insulation meter