Which of the following components is primarily used to amplify electrical signals?

The transistor is primarily used to amplify electrical signals due to its ability to control a larger output current or voltage based on a smaller input signal. This function is essential in a variety of electronic devices and applications, such as audio systems, radio transmitters, and microprocessors.

Transistors operate by utilizing semiconductors, which allow them to manage the flow of electrical current through their terminals. By manipulating the voltage applied to one terminal (the base for bipolar junction transistors, for example), the transistor can significantly increase the current flowing through the other terminals (the collector and emitter). This property makes transistors highly effective for signal amplification, switching applications, and other roles where controlled electronic signals are needed.

In contrast, the other components serve different functions: capacitors store electrical energy, resistors limit current flow, and inductors store energy in a magnetic field, but none are primarily designed to amplify electrical signals like transistors are.