What is the role of a resistor in an electrical circuit?

A resistor plays a vital role in an electrical circuit by limiting the flow of electricity. When incorporated into a circuit, resistors act to impede the flow of electric current, thereby controlling how much current can pass through. This property is essential for ensuring that components in a circuit do not receive too much current, which can lead to overheating or damage.

By using Ohm's law, which relates voltage (V), current (I), and resistance (R), we can see that increasing resistance decreases the current flow for a given voltage. This ability to regulate current is what makes resistors integral to various applications, including setting signal levels, dividing voltages, and protecting sensitive electronic components.

The other options do not accurately describe the primary function of a resistor. For instance, while electrical pressure (voltage) is related to how resistors operate, it is not their role to provide voltage. Similarly, resistors do not measure current; that task is typically performed by ammeters. Lastly, resistors do not increase voltage, as that is typically the function of devices such as transformers.