Description The HOA1875 series consists of an infrared emitting diode facing an NPN silicon phototransistor (HOA1875-001, -002) or photodarlington (HOA1875-003) encased in a black thermoplastic housing. Detector switching takes place whenever an opaque object passes through the slot between emitter and detector. The HOA1875 series has a 0.050 in (1.27 mm) dia. detector aperture and employs metal can packaged components. For additional component information see SE1450, SD1440, and SD1410. Housing material is opaque polysulfone. Housings are soluble in chlorinated hydrocarbons and ketones. Recommended cleaning agents are methanol and isopropanol.