This part is a kind of semiconductor called LM7805.

Function of this product has 3-Terminal 1A Positive Voltage Regulator.

Manufacturers : Fairchild Semiconductor

Image and pinout :

Some of the text within the PDF file :

www.fairchildsemi.com MC78XX/LM78XX/MC78XXA 3-Terminal 1A Positive Voltage Regulator Features • • • • • Output Current up to 1A Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V Thermal Overload Protection Short Circuit Protection Output Transistor Safe Operating Area Protection Description The MC78XX/LM78XX/MC78XXA series of three terminal positive regulators are available in the TO-220/D-PAK package and with several fixed output voltages, making them useful in a wide range of applications. Each type employs internal current limiting, thermal shut down and safe operating area protection, making it essentially indestructible. If adequate heat sinking is provided, they can deliver over 1A output current. Although designed primarily as fixed voltage regulators, these devices ca [ ... ]

LM7805 PDF Datasheet Download