The function of this semiconductor is (MOC78xx) Couplers / Interrupters.
Manufacturers : Motorola
Preview images :
Slotted couplers consist of an infrared emitting diode facing a photodetector in a molded plastic housing. A slot in the housing between the emitter and the detector provides a means of interrupting the signal. A wide selection of standard and custom housings and detector fuctions is available.
1. Cathode 2. Collector 3. Anode 4. Emitter
Motorola offers high performance Infrared Emitters and Detectors for fiber optic systems.
Other data sheets within the file : MOC7812, MOC7813 MOC7821, MOC7822, MOC7823