This part is a kind of semiconductor called B857.

Function of this product has 2SB857.

Manufacturers : Renesas

Image and pinout :

Some of the text within the PDF file :

2SB857, 2SB858 Silicon PNP Triple Diffused Application Low frequency power amplifier complementary pair with 2SD1133 and 2SD1134 Outline TO-220AB 1 2 3 1. Base 2. Collector (Flange) 3. Emitter Absolute Maximum Ratings (Ta = 25°C) Ratings Item Collector to base voltage Collector to emitter voltage Emitter to base voltage Collector current Collector peak current Collector power dissipation Junction temperature Storage temperature Note: 1. Value at T C = 25°C Symbol VCBO VCEO VEBO IC I C(peak) PC * Tj Tstg 1 2SB857 –70 –50 –5 –4 –8 40 150 –45 to +150 2SB858 –70 –60 –5 –4 –8 40 150 –45 to +150 Unit V V V A A W °C °C 2SB857, 2SB858 Electrical Characteristics (Ta = 25°C) 2SB857 Item Collector to base breakdown volta [ ... ]

B857 PDF Datasheet Download