This part is a kind of semiconductor called 2N1671B.

Function of this product has UNIJUNCTION TRANSISTORS.

Manufacturers : Digitron Semiconductors

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Some of the text within the PDF file :

2N1671(A-C) High-reliability discrete products and engineering services since 1977 UNIJUNCTION TRANSISTORS 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 Rating Base 1 – emitter reverse voltage Base 2 – emitter reverse voltage Interbase voltage RMS emitter current Emitter peak current Total power dissipation Maximum junction temperature Storage temperature range Symbol VB1E VB2E VB1B2 IFRMS IEM Ptot TJ Tstg Value 30 30 35 50 2 450 150 -55 to 150 Unit V V V mA A mW °C °C ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise specified) Parameter Symbol Test Conditions Emitter [ ... ]

2N1671B PDF Datasheet Download