This part is a kind of semiconductor called D1857.

Function of this product has 2SD1857.

Manufacturers : Unisonic Technologies

Image and pinout :

Some of the text within the PDF file :

UNISONIC TECHNOLOGIES CO., LTD 2SD1857 POWER TRANSISTOR FEATURES * High breakdown voltage.(BVCEO=120V) * Low collector output capacitance.(Typ.20pF at VCB=10V) * High transition frequency.(fT=80MHz) NPN SILICON TRANSISTOR 1 TO-92 1 TO-92NL *Pb-free plating product number: 2SD1857L ORDERING INFORMATION Order Number Normal Lead Free Plating 2SD1857-x-T92-B 2SD1857L-x-T92-B 2SD1857-x-T92-K 2SD1857L-x-T92-K 2SD1857-x-T9N-B 2SD1857L-x-T9N-B 2SD1857-x-T9N-K 2SD1857L-x-T9N-K 2SD1857-x-T9N-R 2SD1857L-x-T9N-R Package TO-92 TO-92 TO-92NL TO-92NL TO-92NL Pin Assignment 1 2 3 E C B E C B E C B E C B E C B Packing Tape Box Bulk Tape Box Bulk Tape Reel 2SD1857L-x-T92-B (1)Packing Type (2)Package Type (3)Rank (4)Lead Plating (1) B: Tape Box, K: Bulk, R: Tape Reel (2) T92: TO-92 [ ... ]

D1857 PDF Datasheet Download