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Model SPP1
– SINGLE-POINT PEN PROBE
Volume Resistance Measurement for Planar materials
Introduction:
Volume resistance measurements determine if the material has electrical
conducting properties through the bulk of the sample. This test will
measure resistance from top surface to bottom surface of the sample.
There are several possible current paths that the user should understand
and determine which one or combinations of which give the final reading
as shown on the schematic below by Ben Baumgartner (ESDiscovery
2000).
As shown above, the test current can go along the top surface, around
the edges, through the bulk material at various points, within the material
or across the bottom surface before reaching the bottom ground plane.
To ensure that the edges do not contribute to the reading, it is best to cut
the sample into one smaller piece so that none of the outside vertical
edges exists. In this way, the only way the current can flow is down, not
going around along the surfaces.
Procedures:
1. Place sample to be tested on a conductive platform such as
stainless steel or copper plate.
2. For best result, the platform should be thick enough to
accommodate a hole for a banana jack.
