This part is a kind of semiconductor called 2N1776.

Function of this product has PHASE CONTROL SCR.

Manufacturers : DIGITRON

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Some of the text within the PDF file :

2N1770-2N1778, 2N2619 High-reliability discrete products and engineering services since 1977 PHASE CONTROL SCR FEATURES  Available as “HR” (high reliability) screened per MIL-PRF-19500, JANTX level. Add “HR” suffix to base part number.  Available as non-RoHS (Sn/Pb plating), standard, and as RoHS by adding “-PBF” suffix. MAXIMUM RATINGS Ratings Repetitive peak off-state voltage Repetitive peak reverse voltage Non-repetitive peak reverse voltage Symbol VDRM VRRM VRSM 2N1770 25 25 40 2N1771 50 50 75 2N1772 100 100 150 2N1773 150 150 225 2N1774 200 200 300 Units Volts Volts Volts Ratings Repetitive peak off-state voltage Repetitive peak reverse voltage Non-repetitive peak reverse voltage Symbol VDRM VRRM VRSM 2N1775 250 250 350 2N1776 300 300 400 2N1777 400 4 [ ... ]

2N1776 PDF Datasheet Download