What is a capacitor primarily made of?

A capacitor is primarily made of two parallel plates and a dielectric material. This design is crucial for its function of storing electrical energy. The two plates create an electric field when a voltage is applied, allowing the capacitor to hold charge. The dielectric is an insulating material placed between the plates that increases the capacitor's ability to store charge by reducing electric field strength, which helps to prevent current from flowing between the plates. This structure is foundational to how capacitors operate in various electronic circuits, making them essential components in applications involving energy storage, filtering, and timing.

Understanding the composition and structure of capacitors helps to grasp their functionality and the role they play in circuits. Other choices do not accurately represent the fundamental construction and principles behind how capacitors work.