This part is a kind of semiconductor called BC557.

Function of this product has Small Signal Transistors (PNP).

Manufacturers : General Semiconductor

Image and pinout :

Some of the text within the PDF file :

BC556 THRU BC559 Small Signal Transistors (PNP) TO-92 .181 (4.6) min. .492 (12.5) .181 (4.6) .142 (3.6) ♦ ♦ FEATURES PNP Silicon Epitaxial Planar Transistors for switching and AF amplifier applications. These transistors are subdivided into three groups A, B and C according to their current gain. The type BC556 is available in groups A and B, however, the types BC557 and BC558 can be supplied in all three groups. The BC559 is a low-noise type available in all three groups. As complementary types, the NPN transistors BC546 … BC549 are recommended. On special request, these transistors are also manufactured in the pin configuration TO-18. max. ∅ .022 (0.55) .098 (2.5) C B E ♦ MECHANICAL DATA Case: TO-92 Plastic Package Weight: approx. 0.18 g Dimensions in inches and (millimet [ ... ]

BC557 PDF Datasheet Download