An optical encoder can measure rotary position.

• A. True
• B. False
• C. Only linear
• D. Cannot measure

Answer: (A)

An optical encoder converts rotation into electrical signals, letting you determine the shaft’s angle. It uses a light source and a patterned disk (or code track) so as the disk spins, light is blocked or reflected in a way that creates pulses. In an incremental type, each pulse is a small step of rotation; by counting pulses from a known reference you can infer the current rotary position. In an absolute optical encoder, each position has a unique code, so the exact angle is read directly without needing a reference. Because this sensing method is designed to capture angular position, it can measure rotary position. Linear encoders exist too, but that doesn’t change the fact that optical encoders can measure rotation.