What role do resistors play in electrical circuits?

Resistors are fundamental components in electrical circuits, primarily serving the role of controlling the flow of current. By introducing resistance into a circuit, they limit the amount of electric current that can pass through, according to Ohm's law (V = IR, where V is voltage, I is current, and R is resistance). This ability to control current flow is essential for protecting sensitive components from excessive current, ensuring that circuits operate within their designed parameters.

Additionally, resistors play a crucial role in voltage division, allowing engineers to obtain specific voltage levels needed for various components within a circuit. They are also used in applications such as setting biasing conditions in transistors and creating time constants in RC (resistor-capacitor) circuits, which affect the timing of signals.

The other roles mentioned in the options—such as converting AC to DC or amplifying signals—are functions performed by other electronic components like diodes and amplifiers, respectively. Storing energy is primarily the function of capacitors or inductors in a circuit, rather than resistors. Thus, the primary and correct role of resistors in electrical circuits is to control the current flow.