This part is a kind of semiconductor called 78M18A.

Function of this product has POSITIVE VOLTAGE REGULATORS.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

L78M TO-220 TO-220FP DPAK IPAK Features • Output current to 0.5 A • Output voltages of 5; 6; 8; 9; 10; 12; 15; 24 V • Thermal overload protection • Short circuit protection • Output transition SOA protection • Output voltage tolerance: 2% (AB and AC versions) or 4% (C version) • Guaranteed in extended temperature range Precision 500 mA regulators Datasheet - production data Description The L78M series of three-terminal positive regulators is available in TO-220, TO-220FP, DPAK and IPAK packages and with several fixed output voltages, making it useful in a wide range of applications. These regulators can provide local on-card regulation, eliminating the distribution problems associated with single point regulation. Each type employs internal current limiting, thermal shu [ ... ]

78M18A PDF Datasheet Download