Which component is primarily used to filter signals in electrical circuits?

The correct answer is associated with the inductor, as it is primarily used to filter signals in electrical circuits, particularly in applications involving alternating current (AC) signals. Inductors work based on the principle of electromagnetic induction, where they store energy in a magnetic field when current flows through them. This property allows inductors to resist changes in current, making them effective in filtering out higher frequency signals while allowing lower frequency signals to pass.

Inductors are commonly employed in various types of filters, such as low-pass, high-pass, and band-pass filters, to shape the frequency response of signals. Their ability to block or pass different frequency components helps to improve signal quality by reducing noise or unwanted frequencies.

In contrast, resistors primarily serve to limit current and dissipate energy as heat, capacitors store and release electrical energy but are more commonly used for coupling and decoupling signals, and transformers are used to transfer electrical energy between circuits through electromagnetic induction rather than filtering.