The Honeywell SDP8406 is an NPN silicon phototransistor encapsulated in a side-looking clear plastic package. Its design allows for radiation to be received through a plastic lens from the side, making it suitable for applications requiring lateral light detection. The SDP8406 is mechanically and spectrally matched to Honeywell’s SEP8506 and SEP8706 infrared emitting diodes, enabling precise and reliable light sensing in various industrial and consumer applications. It is commonly used in optical sensors, encoders, and light detection systems where a wide acceptance angle and side-view capability are essential.