Which component changes 120 V AC power to a lower AC voltage for other uses?

The component that changes 120 V AC power to a lower AC voltage is a transformer. A transformer operates on the principle of electromagnetic induction and consists of two coils of wire, known as the primary and secondary windings, wound around a magnetic core.

When alternating current flows through the primary winding, it creates a changing magnetic field that induces a voltage in the secondary winding. The ratio of the number of turns in the primary winding to the number of turns in the secondary winding determines whether the voltage is increased or decreased. For instance, if the primary winding has more turns than the secondary, the transformer will reduce the voltage; if the secondary has more turns, it will increase the voltage. This functionality is crucial for various applications, such as powering devices that require lower voltage levels, ensuring that equipment receives the appropriate voltage for safe and effective operation.

Other components listed, such as variable capacitors, transistors, and diodes, serve different purposes in electrical circuits and are not designed to step down AC voltage. A variable capacitor stores electric energy in an electric field and is used in tuning circuits. A transistor is a semiconductor device used for amplification and switching. A diode allows current to flow in one direction only, primarily used for rectification. Thus