This part is a kind of semiconductor called BD131.

Function of this product has SILICON PLANAR EPITAXIAL POWER TRANSISTORS.

Manufacturers : Comset Semiconductors

Image and pinout :

Some of the text within the PDF file :

NPN BD131 SILICON PLANAR EPITAXIAL POWER TRANSISTORS The BD131are NPN transistors mounted in Jedec TO-126 plastic package. Medium power applications. PNP complements are BD132 Compliance to RoHS. ABSOLUTE MAXIMUM RATINGS Symbol VCEO VCBO VEBO IC IB PT TJ TStg Ratings Collector-Emitter Voltage Collector-Base Voltage Emitter-Base Voltage Collector Current Base current (peak value) Reverse base current (peak value) Total power Dissipation Junction Temperature Storage Temperature IC ICM IBM IBM @ Tmb = 60°C Value 45 45 4 3 6 0.5 0.5 15 150 -65 to +150 Unit V V V A A W °C °C www.DataSheet.net/ THERMAL CHARACTERISTICS Symbol RthJ-mb Ratings Thermal Resistance, Junction to mouting base Value 6 Unit K/W ELECTRICAL CHARACTERISTICS TC=25°C unless otherwise noted Symbol ICBO IEBO VCE(S [ ... ]

BD131 PDF Datasheet Download