This part is a kind of semiconductor called 78T12.

Function of this product has 3-TERMINALS 0.5A POSITIVE VOLTAGE REGULATOR.

Manufacturers : Unisonic Technologies

Image and pinout :

Some of the text within the PDF file :

UNISONIC TECHNOLOGIES CO., LTD 78TXX LINEAR INTEGRATED CIRCUIT 3-TERMINALS 0.5A POSITIVE VOLTAGE REGULATOR  DESCRIPTION The UTC 78TXX family is monolithic fixed voltage regulator integrated circuit. They are suitable for applications that required supply current up to 0.5 A.  FEATURE * Output current up to 0.5 A * Fixed output voltage of 5V, 6V, 8V, 9V, 12V, 15V and 18V * Thermal overload shutdown protection * Short circuit current limiting * Output transistor SOA protection available  ORDERING INFORMATION Note: Ordering Number Lead Free Halogen Free 78TXXL-TA3-T 78TXXG-TA3-T 78TXXL-TQ2-R 78TXXG-TQ2-R 78TXXL-TQ2-T 78TXXG-TQ2-T 78TXXL-TQ3-R 78TXXG-TQ3-R 78TXXL-TQ3-T 78TXXG-TQ3-T 1. xx: output voltage, refer to Marking Information 2. Pin Code: I: Input G: GND [ ... ]

78T12 PDF Datasheet Download