This part is a kind of semiconductor called BC639.

Function of this product has SILICON PLANAR EPITAXIAL TRANSISTORS.

Manufacturers : CDIL

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Some of the text within the PDF file :

Continental Device India Limited An ISO/TS 16949, ISO 9001 and ISO 14001 Certified Company SILICON PLANAR EPITAXIAL TRANSISTORS BC635, 637, 639 NPN BC636, 638, 640 PNP TO-92 Plastic Package For Lead Free Parts, Device Part # will be Prefixed with "T" ECB High Current Transistor ABSOLUTE MAXIMUM RATINGS (Ta=25ºC) DESCRIPTION SYMBOL Collector Emitter Voltage Collector Base Voltage Emitter Base Voltage Collector Current Continuous Total Device Dissipation at Ta=25ºC Derate Above 25ºC Total Device Dissipation at Ta=25ºC Total Device Dissipation at Tc=25ºC Derate Above 25ºC Operating And Storage Junction Temperature Range VCEO VCBO VEBO IC PD **PD PD Tj, Tstg THERMAL RESISTANCE Junction to Case Junction to Ambient in free air Junction to Ambient Rth (j-c) Rth (j-a) **Rth (j-a) [ ... ]

BC639 PDF Datasheet Download