PhysicsChapter 6: Electrostatics
Capacitors and Capacitance
Introduction
A capacitor is a device used to store separated electric charge and electrical energy. A basic capacitor has two conductors separated by an insulating material.
Definition
Capacitance
Capacitance is: **C = QV where: `C` = capacitance; `Q` = magnitude of charge on either plate; `V` = potential difference. Unit: farad (F)**
Parallel-Plate Capacitor
For parallel plates: **C = εA/d* Capacitance increases when: plate area increases; permittivity increases. Capacitance decreases when: plate separation increases.
Energy
Energy stored in a capacitor: **U = ½CV² also: U = ½QV and: U = Q²2C**
Uses
* camera flash circuits; * smoothing power supplies; * timing circuits; energy storage; electronic devices.
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Review the key facts, formulas and checks before you move on.Capacitors and Capacitance
Sticky Notes · Quick Revision
C=Q/V
UNIT
- Farad
ENERGY
- ½CV²