The HOA1889 Series consists of two infrared emitting diodes facing two NPN silicon phototransistors (HOA1889-011) or two photodarlington transistors (HOA1889-013) encased in a black thermoplastic housing. Detector switching takes place whenever an opaque object passes through the slot between the the emitter and the detector. The dual channels allow both the speed and the direction of the interrupter to be sensed. Emitters and detectors have a 0,5 mm (0.020 in.) vertical aperture. This feature is ideal for use in applications in which high position resolution is desired. The sensor housing is an opaque thermoplastic with aperture openings for use in applications in which maximum rejection of ambient light is important and maximum position resolution is desired. The HOA1889 Series contains plastic molded components. For additional component information see SEP8506, SDP8406, and SDP8106. Housing material is Valox. Housings are soluble in chlorinated hydrocarbons and ketones. Recommended cleaning agents are methanol and isopropanol.