UL 1577

These requirements cover optical isolators, also called optical couplers or photocouplers:

1. Intended to provide unidirectional signal transfer between dielectrically isolated circuits and,
2. Intended for use in equipment with a supply voltage not exceeding 600 V ac rms or dc.

These requirements cover the electrical insulation properties of the insulation between the isolated circuits of the optical isolator.

These requirements also cover double protection optical isolators that are employed in nominal 125 V, 50 or 60 Hz circuits in radio, video, and television equipment, and similar equipment in applications in which breakdown of the optical isolator may result in a risk of fire, electric shock, or injury to persons.

These requirements do not cover the electrical properties of the separate circuits of the optical isolator.

These requirements apply to optical isolators for use as components in devices and appliances. Compliance of an optical isolator with these requirements does not indicate that the isolator is acceptable for use as a component of an end product without further investigatio