Which devices store electrical energy?

• A. Capacitors
• B. Batteries and capacitors
• C. Transformers
• D. Diodes and transistors

Answer: (B)

Storing electrical energy means keeping energy on hand for use later rather than just guiding or transforming it. Batteries and capacitors do this. A battery stores energy chemically inside the cell and converts it to electrical energy when the circuit needs it. A capacitor stores energy in the electric field between two plates and can release it quickly when a surge is required.

Transformers change voltage and current levels and transfer energy from one circuit to another, but they don’t hold energy themselves. Diodes and transistors are active components that control or switch current; they don’t serve as energy storage devices. (Note that inductors store energy in a magnetic field, but they aren’t part of the listed options.)