Optek, OPI120 DC Input Photodarlington, Photosensor, Phototransistor Output Optocoupler, Through Hole, 5-Pin

The OPI120 and OPI123 series of optically coupled isolators consist of an IR LED and an NPN silicon photosensor. They both contain an 890 nm IR LED. The OPI120 has an NPN phototransistor sensor and the OPI123 has a photodarlington sensor.
This family come in a hermetically sealed housing which is opaque with a transmissive path between the IR LED and the photosensor.
Suitable applications for the OPI120 and OPI123 series include; high voltage isolation between input and output, electrical isolation, and industrial, medical and office equipment.

Optocouplers, Optek