This part is a kind of semiconductor called TYP512.

Function of this product has SCR FOR OVERVOLTAGE PROTECTION.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

® TYP512 TYP1012 SCR FOR OVERVOLTAGE PROTECTION A FEATURES High surge current capability High dI/dt rating High stability and reliability s s s G K DESCRIPTION The TYN512 and TYN1012 Family of Silicon Controlled Rectifiers uses a high performance glass passivated technology. This general purpose Family of Silicon Controlled Rectifiers is designed for overvoltage protection in crowbar circuits application. K A G TO-220AB ABSOLUTE RATINGS (limiting values) Symbol IT(RMS) IT(AV) ITSM I2t ITM dI/dt Tstg Tj Tl Parameter RMS on-state current (180° conduction angle, single phase circuit) Average on-state current (180° conduction angle, single phase circuit) Non repetitive surge peak on-state current (Tj initial = 25°C) I2t value Non repetitive surge peak on-state [ ... ]

TYP512 PDF Datasheet Download