Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E6F
E6F05E6F

Which of the following describes an optical shaft encoder?

Deep Dive: E6F05

The correct answer is A: A device that detects rotation by interrupting a light source with a patterned wheel. Which of the following describes an optical shaft encoder is a device that detects rotation by interrupting a light source with a patterned wheel. Optical encoders detect rotation using light interruption. For amateur radio operators, this is important for optoelectronics knowledge. Understanding this helps when working with encoders.

Why Other Answers Are Wrong

Option B: Incorrect. Device measuring strength of light beam using ADC isn't an encoder - encoder detects rotation by interrupting light. Light measurement isn't encoder. Option C: Incorrect. Optical computing device with fiber optics isn't an encoder - encoder detects rotation by interrupting light. Computing device isn't encoder. Option D: Incorrect. Device generating RTTY signals by rotating light source isn't an encoder - encoder detects rotation by interrupting light. RTTY generation isn't encoder.

Exam Tip

Optical shaft encoder = device that detects rotation by interrupting light source with patterned wheel. Think 'O'ptical 'S'haft 'E'ncoder = 'O'ptical 'S'ensing 'E'ncoder (rotation detection). Optical encoders detect rotation using light interruption. Not light measurement, not computing device, not RTTY generation - just rotation detection by interrupting light.

Memory Aid

Optical shaft encoder = device that detects rotation by interrupting light source with patterned wheel. Think 'O'ptical 'S'haft 'E'ncoder = 'R'otation detection. Optical encoders detect rotation using light interruption. Important for optoelectronics knowledge.

Real-World Example

An optical shaft encoder: It's a device that detects rotation by interrupting a light source with a patterned wheel. As the wheel rotates, it interrupts the light, creating pulses that indicate rotation. This is what it is - rotation detection by interrupting light.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E6F

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

Key Concepts

Optical shaft encoder Detects rotation Interrupting light source Patterned wheel

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E6F topic.