This part is a kind of semiconductor called 2N3055.

Function of this product has COMPLEMENTARY SILICON POWER TRANSISTORS.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

TAB 1 2 TO-3 Figure 1. Internal schematic diagram 2N3055, MJ2955 Complementary power transistors Datasheet - production data Features • Low collector-emitter saturation voltage • Complementary NPN - PNP transistors Applications • General purpose • Audio amplifier Description The devices are manufactured in planar technology with “base island” layout and are suitable for audio, power linear and switching applications. Order code 2N3055 MJ2955 Table 1. Device summary Marking Package 2N3055 MJ2955 TO-3 Packaging Tray November 2013 This is information on a product in full production. DocID4079 Rev 8 1/7 www.st.com Absolute maximum rating 1 Absolute maximum rating 2N3055, MJ2955 Table 2. Absolute maximum rating Symbol Parameter VCBO VCER VCEO VEBO IC IB PTOT Tstg TJ [ ... ]

2N3055 PDF Datasheet Download