Which term is defined as two electrodes or sets of electrodes in the form of plates?

• A. Bus bar
• B. Circuit
• C. Commuter
• D. Capacitor

Answer: (D)

Capacitors are defined by two conductors or sets of conductors arranged as plates with an insulating material between them. When a voltage is applied, charges collect on the facing surfaces of the plates, creating an electric field and storing energy in that field. The amount of stored energy depends on the capacitance, which grows with larger plate area and with a material of higher dielectric constant between the plates, and shrinks as the plates are pulled farther apart. In practical terms, this plate-and-dielectric structure is what gives a capacitor its ability to store and release energy quickly, making it essential for smoothing or coupling signals and for energy storage in power electronics. This is what distinguishes a capacitor from a bus bar (a conductor for distributing power) or a circuit (a complete path for current).