English: Schematic of a parallel plate capacitor with a dielectric spacer. Two plates with area ${\displaystyle A}$ are separated by a distance ${\displaystyle d}$. When a charge ${\displaystyle \pm {}Q}$ is moved between the plates, an electric field ${\displaystyle E}$ exists in the region between the plates. The dielectric material becomes polarised due to the charge displacement, reducing the total internal field, and increasing the capacitance.