Direct Current

Current and Capacitors

Seat Experiment

Using a supercapacitor, some wire, a Genecon and a light bulb we will explore the charging and discharging of a capacitor.

First test the Genecon without a load. Does it turn easily? Clip the leads together and turn the handle. This represents a full load on the Genecon. What happens? Connect the generator to the light bulb as shown. Turn the Genecon handle steadily and slowly.

Q1: Describe and discuss these effects in terms of work, energy and light.

Connect the bulb in parallel with the capacitor and Genecon. Charge the capacitor and remove the Genecon. What happens?

Q2: Describe how lamp brightness changes with time.

Q3: What does this tell you about the discharge of a capacitor as compared to the discharge of a battery?

Now connect just the Genecon and the capacitor in parallel. Charge the capacitor and leave the Genecon attached. What happens? What causes this effect?

Q4: How does the discharge of a capacitor compare to that of a battery?

Q5: Why does the Genecon become a motor in part 3?

Q6: Draw a circuit diagram for each operation above. 

Q7: Try to determine what direction current would flow in the circuits you just drew.

Q8: What would happen if you left the Genecon and bulb in parallel to the capacitor after you charged the capacitor. Try it. Describe and discuss the results and your prediction.


Chabay & Sherwood, Electric and Magnetic Interactions, Carnegie Melon University

Priscilla W. Laws, Workshop Physics, Dickinson College

Seat Activities