Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E6C
E6C03E6C

What is tri-state logic?

Deep Dive: E6C03

The correct answer is A: Logic devices with 0, 1, and high-impedance output states. What is tri-state logic is logic devices with 0, 1, and high-impedance output states. Tri-state logic has three states: 0, 1, and high-Z. For amateur radio operators, this is important for digital circuits. Understanding this helps when working with digital logic.

Why Other Answers Are Wrong

Option B: Incorrect. Logic devices utilizing ternary math isn't tri-state - tri-state is 0, 1, high-Z. Ternary math isn't tri-state. Option C: Incorrect. Logic with three output impedances selectable isn't tri-state - tri-state is 0, 1, high-Z. Three impedances isn't tri-state. Option D: Incorrect. Counter with eight states isn't tri-state - tri-state is 0, 1, high-Z. Eight states isn't tri-state.

Exam Tip

Tri-state logic = logic devices with 0, 1, and high-impedance output states. Think 'T'ri-'S'tate = 'T'hree 'S'tates (0, 1, high-Z). Tri-state logic has three states: 0, 1, and high-Z. Not ternary math, not three impedances, not eight states - just 0, 1, high-Z.

Memory Aid

Tri-state logic = logic devices with 0, 1, and high-impedance output states. Think 'T'ri-'S'tate = '3' states. Tri-state logic has three states: 0, 1, and high-Z. Important for digital circuits.

Real-World Example

Tri-state logic: It's logic devices with 0, 1, and high-impedance output states. The high-impedance state allows multiple devices to share a bus without conflict. This is what tri-state logic is - 0, 1, and high-Z states.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E6C

Reference: 2024-2028 Question Pool · E6 - Circuit Components

Key Concepts

Tri-state logic Logic devices 0, 1, and high-impedance output states

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E6C topic.