Optocoupler (also known as Opto-isolator) device manufactured by Hewlett-Packard, 6N139. An optocoupler provides electrical isolation between circuits by using light. One half of the device contains a small light emitting element (typically a LED - Light Emitting Diode) which is optically connected (typically using glass) to a light sensitive element (photo-transistor). This allows siginalling between two circuits with electrical isolation. Often used in computer communication.

Physical Description

Small black rectangular plastic package with 8 gold-plated pins.

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