Which of the following describes an optical shaft encoder?
A device that detects rotation by interrupting a light source with a patterned wheel✓Bonne réponse
A device that measures the strength of a beam of light using analog-to-digital conversion
An optical computing device in which light is coupled between devices by fiber optics
A device for generating RTTY signals by means of a rotating light source
Explication
An optical shaft encoder puts a slotted or patterned wheel on the shaft between a light source and a detector, so turning the shaft chops the beam into pulses that circuitry counts to derive position, direction, and speed — the mechanism behind most VFO tuning knobs. The other choices describe a light meter, fiber-optic coupling, and an RTTY generator.