What is the primary function of a transistor?

The primary function of a transistor is to amplify or switch electronic signals. Transistors are semiconductor devices that play a crucial role in modern electronic circuits by controlling the flow of electrical current. When a small input current is applied to one of its terminals, it can regulate a much larger current flowing through another terminal, effectively amplifying the signal.

Additionally, transistors can act as switches, allowing them to turn electrical signals on or off in a circuit. This dual capability makes them essential in various applications, including audio devices, computers, and communications equipment.

The other options define functions associated with different electrical components. For instance, converting direct current to alternating current is typically handled by an inverter. Measuring voltage is done using a voltmeter, and storing electrical energy is the role of capacitors or batteries. Thus, the amplification and switching functions of transistors uniquely position them at the heart of many electronic systems.