Parallel plate capacitor

Definition

A parallel plate capacitor consists of two conductive plates separated by a dielectric material. It stores electrical energy in the electric field created between the plates.

5 Must Know Facts For Your Next Test

1. The capacitance $C$ of a parallel plate capacitor is given by $C = \epsilon_0 \frac{A}{d}$, where $\epsilon_0$ is the permittivity of free space, $A$ is the area of one plate, and $d$ is the separation between the plates.
2. Introducing a dielectric material between the plates increases the capacitance by a factor called the dielectric constant (k).
3. The electric field $E$ between the plates is uniform and given by $E = \frac{V}{d}$, where $V$ is the voltage across the plates.
4. The energy stored in a parallel plate capacitor is given by $U = \frac{1}{2}CV^2$.
5. If the distance between the plates increases while maintaining constant charge, the voltage also increases.

Review Questions

• What happens to the capacitance of a parallel plate capacitor if you insert a dielectric material?
• How does increasing the area of one of the plates affect the capacitance?
• What formula relates electric field and voltage for a parallel plate capacitor?

Related terms

Dielectric Material: An insulating material placed between capacitor plates that increases its capacitance by reducing electric field strength.

Electric Field:

A vector field around charged particles that represents forces exerted on other charges; in capacitors, it is created between two conductive plates.

Permittivity:

$\epsilon_0$, also known as permittivity of free space, it quantifies how an electric field affects and is affected by a vacuum or dielectric medium.