Potential, Voltage and Capacitors
How the electric field stores energy in charges — and how a capacitor stores it for us
Big Idea: An electric field can do work on a charge, just as gravity does work on a falling ball. The energy a charge has because of its place in the field is electric potential energy. Sharing that energy out "per unit charge" gives us two everyday quantities — potential and voltage — and a capacitor is a simple device built to store this energy and give it back.
By the end you will be able to:
- explain the work of the electric field and electric potential energy,
- define potential and voltage (potential difference) and use A = qU,
- state the unit volt and that 1 V = 1 J/C,
- describe a capacitor and use capacitance C = q/U with the unit farad,
- name real uses of capacitors and correct common mistakes.