1. Capacitance
Section Pages

2. What is a capacitor?
2 parallel conducting plates, separated by an insulator
Insulator prevents the capacitor plates from sparking a discharge to each other
Step one: Charging
When the switch is closed, electrons begin to flow (not exactly a current)
Electrons move from one plate to the other

3. Capacitor charging
Electrons move from the positive plate to the negative plate
Energy required to do so
Energy supplied by cell (the only source of emf)

4. Fully charged capacitor
More and more energy is needed to move electrons as the plates gain charge
The capacitor is fully charged when the energy needed to move the electron is more than what is available from the cell
Potential difference between the plates is equivalent to the pd of the cell (emf source)
(during charging, capacitor pd will be less than the cell’s emf)

5. Quantifying Capacitance
Capacitance: The ratio of the charge stored on the plates to the potential difference between the plates.
Unit = Coulomb per Volt
C·V-1 = F (farad)