This part is a kind of semiconductor called BC172B.

Function of this product has (BC171 - BC174) NPN Silicon Planar Transistors.

Manufacturers : CDIL

Image and pinout :

Some of the text within the PDF file :

Continental Device India Limited An IS/ISO 9002 and IECQ Certified Manufacturer IS/ISO 9002 Lic# QSC/L- 000019.2 NPN SILICON PLANAR TRANSISTORS BC171 , A, B BC172, A, B, C BC174, A, B TO-92 Plastic Package C BE Amplifier Transistors ABSOLUTE MAXIMUM RATINGS (Ta=25ºC unless specified otherwise) DESCRIPTION Collector Emitter Voltage Collector Base Voltage Emitter Base Voltage Collector Current Continuous Total Device Dissipation @ Ta=25ºC Derate Above 25ºC Total Device Dissipation @ Tc=25ºC Derate Above 25ºC Operating And Storage Junction Temperature Range THERMAL RESISTANCE Junction to ambient Junction to case SYMBOL VCEO VCBO VEBO IC PD PD Tj, Tstg BC174 BC171 65 80 45 50 6 100 350 2.8 1.0 8.0 -55 to +150 BC172 25 30 UNIT V V V mA mW mW/ºC W mW/ºC ºC Rth [ ... ]

BC172B PDF Datasheet Download