Which device provides feedback by using light to detect rotation, typically in a mechanical system?

Which device provides feedback by using light to detect rotation, typically in a mechanical system?

• A. Tachometer
• B. Optical Encoder
• C. Proximity Sensor
• D. Linear Scale

Answer: (B)

Rotational feedback that uses light to read a pattern is provided by an optical encoder. It places a light source and sensors so that a coded disk or reflective marks either interrupt or modulate the light as the shaft turns. The sensors convert these light changes into electrical pulses; counting the pulses gives angular position and speed, and with two out-of-phase channels you can also determine direction. This light-based sensing is what makes it ideal for precise rotational feedback in mechanical systems. A tachometer uses non-light methods (like magnetic or Hall effects) to measure speed but not position. A proximity sensor detects whether something is nearby, not rotational position. A linear scale measures linear displacement, not rotation. So the optical encoder is the device that provides rotational feedback using light.

Rotational feedback that uses light to read a pattern is provided by an optical encoder. It places a light source and sensors so that a coded disk or reflective marks either interrupt or modulate the light as the shaft turns. The sensors convert these light changes into electrical pulses; counting the pulses gives angular position and speed, and with two out-of-phase channels you can also determine direction. This light-based sensing is what makes it ideal for precise rotational feedback in mechanical systems. A tachometer uses non-light methods (like magnetic or Hall effects) to measure speed but not position. A proximity sensor detects whether something is nearby, not rotational position. A linear scale measures linear displacement, not rotation. So the optical encoder is the device that provides rotational feedback using light.