This part is a kind of semiconductor called MC7812CT.

Function of this product has (MC78xxCT) 3-Terminal Fixed Positive Voltage Regulator.

Manufacturers : Vishay

Image and pinout :

Some of the text within the PDF file :

MC78xxCT Series New Product Vishay Semiconductor 3-Terminal Fixed Positive Voltage Regulators MC78xxCT TO-220AB Pin Definition 1. Input 2. Ground 3. Output (Heatsink/ tab connected to pin 2) Description These voltage regulators are monolithic integrated circuits designed as fixed-voltage regulators for a wide variety of applications including local, on-card regulation. These regulators employ internal current limiting, thermal shutdown, and safe-area compensation. With adequate heatsinking the MC78xxCT can deliver output currents in excess of 1.5 ampere. Although designed primarily as a fixed voltage regulator, these devices can be used with external components to obtain adjustable voltages with currents. Output 1 2 3 Standard Application Input MC78xx Features • Output current in [ ... ]

MC7812CT PDF Datasheet Download