What electrical component is usually composed of a coil of wire?

The electrical component typically composed of a coil of wire is the inductor. An inductor operates on the principle of electromagnetic induction. When an electric current flows through the coil of wire, a magnetic field is generated around it. This property allows inductors to store energy in the magnetic field and is fundamental in various applications such as filters, oscillators, and in power supply circuits.

Inductors are characterized by their inductance, which measures how effectively they can induce voltage as a result of changes in current. This feature makes inductors essential components in many electronic devices, especially in radio frequency circuits where they work alongside capacitors to create tuned circuits.

In contrast, a switch is a control device that opens or closes an electrical circuit, while a capacitor is designed to store electrical energy temporarily, and a diode allows current to pass in one direction only. These components have different functions and structures that do not involve simply being a coil of wire like an inductor.