Demos: 6C-01 Growth & Decay of Capacitor Charge
By using two different resistances and a capacitor in series, the growth and decay of the charge on a capacitor is shown.
Directions: First place the 100K resistor in the circuit. Move the switch to the charging circuit and wait for the capacitor to charge, as evidenced by the maximum reading from the projectable voltmeter. Then move the switch to the discharge position and note the time it takes for the capacitor to discharge. Repeat, using the 1 M resistor.
Suggestions for Presentation: Show the circuit to the class and have them predict what the voltmeter will read as the switch is thrown to the discharge position. Will it be the same as when charging? Then ask how the value of the resistance will change the results.
Applications: Electronic circuits, especially those in which a charged capacitor plays the role of a battery to maintain voltage while the real battery is being changed.