What is the primary function of a resistor?

The primary function of a resistor is to inhibit the flow of current. Resistors are components used in electrical circuits to limit the amount of current that can pass through, which is essential for controlling the voltage levels and protecting sensitive components from damage caused by excessive current. By introducing a specific amount of resistance into a circuit, resistors help to ensure that the circuit operates safely and effectively, allowing for the proper functioning of electrical and electronic devices. This function is critical in managing how electrical energy is distributed within a circuit, ensuring stability and reliability.

In contrast, other options reflect different functionalities that do not align with the purpose of resistors. For instance, resistors do not increase voltage; that function is typically associated with transformers or other circuit configurations designed to boost voltage levels. Converting energy types is more related to devices like capacitors or inductors, which can store and release energy in various forms. Additionally, allowing current to flow in both directions is characteristic of components like diodes, which are designed specifically for that purpose, not resistors. Thus, the correct answer highlights the essential role of resistors in regulating current and voltage in electrical circuits.