Charge Producers and Proof Planes
012-07144A
2
➤
NOTE:
You can then use an electrometer
and a Faraday ice pail (ES-9042A) to measure
the charge density on the proof plane, as
shown in the following illustration.
Other
The conductive disk material is carbon-filled black
polycarbonate (about 10
3
Ω
) with an aluminum disk.
The nonconductive neck is white polycarbonate (about
10
14
Ω
).
Limited Warranty
PASCO scientific warrants the product to be free from
defects in materials and workmanship for a period of one
year from the date of shipment to the customer. PASCO
will repair or replace, at its option, any part of the product
which is deemed to be defective in material or
workmanship. The warranty does not cover damage to
the product caused by abuse or improper use.
Determination of whether a product failure is the result of
a manufacturing defect or improper use by the customer
shall be made solely by PASCO scientific. Responsibility
for the return of equipment for warranty repair belongs to
the customer. Equipment must be properly packed to
prevent damage and shipped postage or freight prepaid.
(Damage caused by improper packing of the equipment
for return shipment will not be covered by the warranty.)
Shipping costs for returning the equipment after repair will
be paid by PASCO scientific.
Address:
PASCO scientific
10101 Foothills Blvd.
Roseville, CA 95747-7100
Phone:
(916) 786-3800
FAX:
(916) 786-8905
email:
web:
www.pasco.com
By touching the proof plane to a surface, it will acquire
the same charge distribution as the surface. By measuring
the charge on the proof plane, the charge density on 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 the proof plane is touched to a conductor, 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
conductive surface. The following illustration shows the
recommended method for using the proof plane to sample
the charge on a conductive sphere.
➤
NOTE:
To accurately sample charge density,
the conductor should be considerably larger than
the disk of the proof plane and have a relatively
large radius of curvature at the point from which
the sample is taken. However, the proof plane can
be used to test for charge polarity on conductors
of any shape.
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charged proof plane
in Faraday ice pail
signal lead
ground lead
Faraday ice pail and shield
charged conductive
sphere
Proof plane disk IS NOT
tangent to surface of
conductor.
Proof plane disk IS
tangent to surface of
conductor.
NO!
YES!
