What type of electrical component consists of conductive surfaces separated by an insulator?

The correct answer is a capacitor. A capacitor is an electrical component that stores energy in the form of an electric field, formed by two conductive plates that are separated by an insulating material known as a dielectric. When voltage is applied across the conductive surfaces, an electric charge accumulates on the plates, allowing the capacitor to store electrical energy.

This operation relies on the presence of the insulating layer between the conductive surfaces, which prevents direct current from flowing between them while allowing an alternating current to pass through when it is charged or discharged. The dielectric material is crucial because it increases the capacitor's ability to store charge by enhancing the electric field strength between the plates. In essence, the fundamental function of a capacitor is to temporarily hold electrical energy, making it an essential component in various electronic circuits, including filtering applications and energy storage.

On the other hand, a resistor is used to limit current flow in a circuit, a potentiometer serves as a variable resistor that adjusts voltage levels, and an oscillator generates periodic signals, so none of these components encapsulate the relationship of conductive surfaces separated by an insulator like a capacitor does.