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Model No. ES-9080
Basic Electrostatics System
7
Variable Capacitor (ES-9079)
The PASCO experimental variable
capacitor consists of two metal plates, 20
cm in diameter, which can be adjusted to
various separations. The movable plate is
mounted on a calibrated slide which gives
the plate separation directly in
centimeters. Binding posts are provided
for electrical connection to each plate.
Three plastic spacers are attached to the
fixed plate so that when the movable
plate is made to touch these spacers, the
plate separation is 1 mm.
Use a low-capacitance cable to connect the plates to the electrometer.
Keep the leads of the cables separated as much as possible to minimize
capacitance.
It is very important that the plates of the capacitor remain parallel. It is
possible that through mishandling, they will cease to be parallel, and
adjustments must be made. On the back side of the fixed plate is a
second, smaller plate with three set screws. By adjusting these three
screws, the two plates may be kept parallel.
Keep the clear acrylic plate supports clean to prevent charge leakage
from the plates.
Charge Producers and Proof Plane (ES-9057A)
The Charge Producers and the
Proof Plane are electrostatic
components for use with the
PASCO Electrostatic System. The
charge producers are used to
generate charges by contact. The
proof plane is used to measure
charge density on a charged
surface.
The charge producers consist of
two wands, one with blue and one
with white material attached to a conductive disk, as shown in Figure
4. If the blue and white surfaces are briskly rubbed together, the white
surface acquires a positive charge, and the blue surface acquires a
negative charge.
Figure 3: Variable
Capacitor
Figure 4: Charge Producers
white
surface
blue
surface
non-conductive neck
conductive
disks