What is the primary function of a transistor?

The primary function of a transistor is to amplify or switch electronic signals. Transistors are fundamental components in modern electronics, used in various applications such as amplifiers, oscillators, and digital circuits. When employed as an amplifier, a small input signal can control a much larger output signal, making them invaluable in audio equipment, communications devices, and many other areas where signal boost is required.

In addition to amplification, transistors can also function as switches, allowing them to control the flow of electrical current in a circuit. This ability to switch on and off rapidly enables them to perform complex operations in digital systems, like those found in computers. The operation of a transistor is based on the manipulation of charge carriers (electrons and holes) within semiconductor materials, allowing precise control over current flow.

The other options relate to different electrical concepts. Storing electrical energy is typically a function of capacitors or batteries. Allowing current to flow in both directions is characteristic of diodes. Regulating voltage is primarily the role of voltage regulators or specific circuit components designed for that purpose. Each of these functions is essential in electrical engineering but does not describe the primary role of a transistor, which is centered on amplification and switching of electronic signals.