Which component is commonly used to increase electrical resistance?

A resistor is specifically designed to increase electrical resistance within a circuit. Its primary function is to control the flow of electric current by providing a opposition to the flow. Resistors are widely used in various electronic components and circuits to ensure that current levels are appropriate for the other elements in the circuit, thus protecting sensitive components and ensuring the desired operation of the circuit is maintained.

In contrast, capacitors store electrical energy temporarily and are used to manage voltage levels and filter signals, while inductors store energy in a magnetic field and are predominantly used in applications like filtering and energy storage in alternating current (AC) circuits. Transformers, on the other hand, function to change the voltage level in AC circuits but do not directly increase resistance; instead, they operate on the principle of electromagnetic induction to modify voltage and current levels. This functionality highlights the unique role of resistors in varying resistance specifically, as opposed to the capabilities of the other components listed.