Instruction manual

Basic Electrostatics System Model No. ES-9080

4. Observe how the potential difference reading from the electrometer

varies as more charge is put in the capacitor.

5. Double the plate separation and repeat the experience. What

happens to the potential now? Compare the values to the previous

case.

3B.2: Q Measured, C Variable, V Constant

1. Figure 3.3 above shows the equipment set up. The Parallel Plate

capacitor has an initial plate separation of 6 cm and is connected to the

voltage source, set at 2000 VDC. The Faraday Ice Pail is connected to

the electrometer, and the electrometer is grounded to earth.

2. Momentarily ground a proof plane and then use it to examine the

charge density of the capacitor, using the ice pail to measure the

charge. Investigate the charge density at various points on the

plates — both on the inner and the outer surfaces. How does the

charge density vary over the plate?

3. Choose a point near the center of one capacitor plate and measure

charge density in this area at different plate separations. (Keep in

mind whether you are increasing or decreasing the capacitance by

moving the plates.) How does the charge vary with capacitance?

3B.3 Q Measured, V Variable, C Constant

1. Figure 3.3 shows the equipment set up, which is identical to the setup

for B2. The Parallel Plate capacitor has an initial plate separation of 6

cm and is connected to the voltage source, set initially at 3000 VDC.

The Faraday Ice Pail is connected to the electrometer and the

electrometer is grounded to earth.

2. Keep the plate separation constant and change the potential across

the plates by changing the setting of the voltage source. You have

red lead

black lead

2000 V

Figure 3.3: Demonstration Setup