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Optical Isolators
UL 1577
1 Scope
1.1 These requirements cover optical isolators, also called optical couplers or photocouplers:

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

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

1.3 These requirements also cover double protection optical isolators that are employed in circuits rated up to 250 V, 50 or 60 Hz, 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.

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

1.5 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 investigation.

1.6 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of fire or of electric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this standard does not comply with this standard. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.