!
Model No. ES-9080
Basic Electrostatics System
9
By touching the proof plane
to a surface, the proof plane
will acquire the same charge
distribution as the section of
the surface it touched (See
Figure 6). By measuring the
charge on the proof plane,
the charge density on that
part of the surface can be
determined. The greater the
charge on the proof plane,
the greater the charge
density on the surface where
the proof plane made contact.
When a proof plane is touched to a conductive surface, the proof plane
becomes part of the conductive surface. If the effect on the shape of the
surface is significant, the sampling of the charge density will not be
accurate. Therefore, always touch the proof plane to the conductor in
such a way as to minimize the distortion of the shape of the surface.
Figure 7 shows the recommended method for using the proof plane to
sample charge on a conductive sphere.
in sampled area
equals charge
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
charge in proof plane
area sampled
Figure 6: Conductive Sphere
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
Figure 7: Proper use of a proof plane to
sample charge
charged spheres
Surface of the
proof plane IS
tangent to the
surface of the
conductor.
Surface of the
proof plane IS
NOT tangent to
the surface of
the conductor.
