Which component is typically used to control voltage levels in circuits?

The component that is typically used to control voltage levels in circuits is the transformer. A transformer functions by transferring electrical energy through inductively coupled conductors—the transformer's coils. By varying the number of turns of wire in the primary coil (input) versus the secondary coil (output), a transformer can either step up (increase) or step down (decrease) voltage levels without changing the overall power in the circuit, provided that losses are minimal. This capability makes transformers essential in power distribution systems, where voltage levels need to be adjusted to efficiently transmit electricity over long distances and ensure safe and usable voltage levels for end-users.

While inductors, resistors, and capacitors play crucial roles in circuits—such as filtering, limiting current, and storing energy—they do not primarily function to control voltage levels like transformers do. Inductors primarily resist changes in current, resistors limit current flow and dissipate energy, and capacitors store energy in an electric field. Each of these components has its specific applications, but when it comes to regulating and manipulating voltage within circuits, transformers are the preferred choice.