What is one key function of inductors in electrical circuits?

Inductors play a crucial role in electrical circuits primarily by storing energy in a magnetic field and opposing changes in current. When an electrical current passes through an inductor, it generates a magnetic field around itself. This magnetic field has the ability to store energy, which can be released back into the circuit when needed.

Inductors resist changes in current flow due to the principle of electromagnetic induction; when the current through an inductor attempts to change, the magnetic field reacts in a way that generates a voltage (known as back electromotive force or back EMF). This property makes inductors essential for filtering signals, smoothing out current in power supplies, and in various applications such as transformers and motors.

The other choices do not accurately describe the primary function of inductors. For example, while the option mentions converting magnetic energy to electrical energy, this is more characteristic of transformers rather than inductors. Similarly, serving as direct current sources and amplifying electrical signals represent roles more suited to other components, such as batteries and transistors, respectively.