PASCO ES-9080A - Proof Plane

Basic Electrostatics System Model No. ES-9080
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The Proof Plane
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Figure 5: Proof Plane
handle
surface
aluminum
(white)
non-conductive neck
(black)
conductive disk
NOTE: The proof
planes can be used to
test for charge polarity
on conductors of any
shape. However, for
accurate readings of
charge density, the con-
ductor surface sam-
pled has to be
considerably larger
than the disk of the
proof plane and have a
relatively large radius
of curvature at the
point of contact.