T6B05: What type of transistor has a gate, drain, and source

Q: What type of transistor has a gate, drain, and source?

The correct answer is B: Field-effect. The correct answer is B: Field-effect. A Field-effect transistor (FET) is the type of transistor that has a gate, drain, and source. These are the three terminals of a FET, corresponding to the base, collector, and emitter of a bipolar transistor. Field-effect transistors (FETs) have three terminals: gate (control), drain (output), and source (input). The gate controls current flow between source and drain through an electric field (hence 'field-effect'). FETs include MOSFETs (Metal-Oxide-Semiconductor FETs) and JFETs (Junction FETs). They're voltage-controlled devices (gate voltage controls drain-source current), unlike bipolar transistors which are current-controlled. FETs are widely used in amplifiers, switches, and digital circuits.

Updated: Dec 9, 2025 | Source: 2022-2026 Question Pool | Topic: T6B

T6B05T6B

What type of transistor has a gate, drain, and source?

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Deep Dive: T6B05

The correct answer is B: Field-effect. A Field-effect transistor (FET) is the type of transistor that has a gate, drain, and source. These are the three terminals of a FET, corresponding to the base, collector, and emitter of a bipolar transistor. Field-effect transistors (FETs) have three terminals: gate (control), drain (output), and source (input). The gate controls current flow between source and drain through an electric field (hence 'field-effect'). FETs include MOSFETs (Metal-Oxide-Semiconductor FETs) and JFETs (Junction FETs). They're voltage-controlled devices (gate voltage controls drain-source current), unlike bipolar transistors which are current-controlled. FETs are widely used in amplifiers, switches, and digital circuits.

Why Other Answers Are Wrong

Option A: Incorrect. Varistors are voltage-dependent resistors, not transistors. They don't have gate, drain, and source terminals - they're two-terminal devices. Option C: Incorrect. Tesla-effect is not a real transistor type. This is a distractor - there's no such thing as a Tesla-effect transistor. Option D: Incorrect. Bipolar junction transistors (BJTs) have emitter, base, and collector terminals, not gate, drain, and source. Gate/drain/source are FET terminals.

Exam Tip

FET = Gate, drain, source. Remember: Field-effect transistors (FETs) have gate, drain, and source terminals - these are the three terminals of a FET.

Memory Aid

**F**ET = **G**ate, **D**rain, **S**ource (think 'FET = GDS')

Real-World Example

You're working with a MOSFET (a type of FET) in an amplifier circuit. It has three terminals: gate (control input), drain (output), and source (common). The gate voltage controls current flow between source and drain. This is the structure of all field-effect transistors.

Source & Coverage

Question Pool: 2022-2026 Question Pool

Subelement: T6B

Reference: 2022-2026 Question Pool · T6 - Electrical components

Key Concepts

Field-effect transistor FET Gate, drain, source Semiconductor devices

Verified Content

Question from the official FCC Technician Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the T6B topic.