This part is a kind of semiconductor called MOC3061.

Function of this product has 6-Pin DIP Zero-Cross Optoisolators Triac Driver Output.

Manufacturers : Fairchild

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Some of the text within the PDF file :

GlobalOptoisolator™ 6-Pin DIP Zero-Cross Optoisolators Triac Driver Output (600 Volts Peak) The MOC3061, MOC3062 and MOC3063 devices consist of gallium arsenide infrared emitting diodes optically coupled to monolithic silicon detectors performing the functions of Zero Voltage Crossing bilateral triac drivers. They are designed for use with a triac in the interface of logic systems to equipment powered from 115/240 Vac lines, such as solid–state relays, industrial controls, motors, solenoids and consumer appliances, etc. • Simplifies Logic Control of 115/240 Vac Power • Zero Voltage Crossing • dv/dt of 1500 V/µs Typical, 600 V/µs Guaranteed • To order devices that are tested and marked per VDE 0884 requirements, the suffix ”V” must be included at end of part number. V [ ... ]

MOC3061 PDF Datasheet Download