ARRL Technician Practice Exam

Which of the following electronic components can amplify signals?

1. Resistor

2. Capacitor

3. Transistor

4. Inductor

The correct answer is: Transistor

The correct answer is a transistor, which is a fundamental electronic component widely used for amplifying signals. Transistors work by controlling electrical current flow and, through this mechanism, they can increase the power of the input signal. This amplification capability allows transistors to be integral in a variety of applications, including radios, televisions, and various circuitry in communication systems. Transistors can operate in different modes (such as common emitter, common base, and common collector), which determine how the input signal affects the output signal in terms of voltage and current gain. This characteristic distinguishes transistors as key players in electronics, particularly in amplification circuits. On the other hand, resistors, capacitors, and inductors do not possess amplification properties. Resistors are used to limit current flow and divide voltages, capacitors store and release electrical energy, and inductors store energy in a magnetic field when current flows through them. While each of these components plays a crucial role in electronic circuits, it is the transistor that specifically provides the necessary amplification of signals.