The OPB732CZ is a non-focused reflective sensor designed to operate over a distance of 0.05” [1.27mm] to 1.5” [38.1mm]. The OPB732CZ is tested on a white 90% reflective card. Other surfaces will give different signal levels. The sensor operates by emitting Infrared (IR) light from the LED which then strikes an object and is reflected back toward the phototransistor sensor. The phototransistor collector current is dependent upon the amount of reflected light which decrease with distance. The graph on this page shows the effect of target distance on the output current.