ARRL Technician Practice Exam

What are the three electrodes of a field effect transistor?

1. Source, gate, and drain

2. Emitter, collector, and base

3. Input, output, and control

4. Positive, negative, and ground

The correct answer is: Source, gate, and drain

The three electrodes of a field effect transistor (FET) are indeed the source, gate, and drain. In a FET, the source is the terminal that supplies carriers (electrons or holes), the gate is the control electrode that modulates the conductivity between the source and the drain, and the drain is the terminal through which the carriers exit the transistor. The proper functioning of a FET relies on the ability of the gate to control the flow of current between the source and the drain by creating an electric field. This makes FETs widely used in various electronic devices, including amplifiers and switches, due to their high input impedance and efficient operation. The other options refer to components from different types of transistors or circuits. For instance, the emitter, collector, and base are terms related to bipolar junction transistors (BJTs), which operate on different principles than FETs. Similarly, the input, output, and control terms are more vague and do not specify the actual names of the terminals associated with FETs. Lastly, the terms positive, negative, and ground pertain more broadly to circuit connections and power supply configurations rather than to the specific electrodes of a FET.