The change in capacitance due to changing plate separation can be demonstrated using digital multimeter that measures capacitance. The output can be sent to a computer and displayed on movie screen. Change in capacitance due to changing dielectric can also be demonstrated.

Setup Requirements: Assembled as needed.  Use document camera or web camera to put picture of meter on movie screen. This can also be used to show effect of a dielectric. Insert physics text between plates.

Equations: CV=Q. C proportional to 1/d.

Safety Issues: None

Charge a large electrolytic capacitor and short with a screwdriver. Demonstrate energy stored in capacitor. Also safety issue. Large capacitors can remain charged after device is shut off. 

Setup Requirements: Minimal

Equations: None

Safety Issues: Possible shock, sparks

5C30.30 Capacitor and a Light Bulb

A large electrolytic capacitor, a light bulb, and a DC supply in series show a long time constant.

Setup Requirements: Assembled as needed

Equations: Time constant = RC

Safety Issues: Possible shock

5C30.31 Capacitor and Light Bulbs

Variation of capacitor and bulb uses 5 bulbs to visually show how changing resistance affects decay time. A capacitor is charged from 6V battery. It is then discharged through light bulbs in series or parallel. A stop watch can be used to measure times.

Setup Requirements: Assembled as needed

Equations: Time constant = RC.

Safety Issues: none

5C30.35 Charging Capacitor with Generator

Hook a Genecon generator to the 1 farad capacitor. Note that as you turn the handle it becomes easier as the capacitor charges up. The rate at which the voltage changes is reduced as the capacitor charges. If you let go, the handle will continue to turn. Ask class to explain what is happening.

Setup Requirements: Assembled as needed. Device to visually demonstrate current flow could be used with this demonstration.

Equations: Equations for voltage on capacitor as it charges and current & torque in generator apply.

Safety Issues: Capacitor has 5v limit.