A transistor contains how many terminals?

A transistor contains how many terminals?

• A. Two
• B. Three
• C. Four
• D. Five

Answer: (B)

Transistors have three terminals. This is what lets them function as amplifiers or switches: one terminal is for the input control, one is for the output path, and the third serves as a common reference between the input and output. In a bipolar transistor, those terminals are base, collector, and emitter. A small current at the base controls a much larger current between the collector and emitter. In a field-effect transistor, the gate controls the current between source and drain, but there are still three connections. If you only had two terminals, the device would act like a diode, not a transistor; four or five terminals would indicate extra connections or multiple devices rather than a single transistor.

Transistors have three terminals. This is what lets them function as amplifiers or switches: one terminal is for the input control, one is for the output path, and the third serves as a common reference between the input and output. In a bipolar transistor, those terminals are base, collector, and emitter. A small current at the base controls a much larger current between the collector and emitter. In a field-effect transistor, the gate controls the current between source and drain, but there are still three connections. If you only had two terminals, the device would act like a diode, not a transistor; four or five terminals would indicate extra connections or multiple devices rather than a single transistor.