This part is a kind of semiconductor called LM7905.

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

Manufacturers : Fairchild Semiconductor

Image and pinout :

Some of the text within the PDF file :

www.fairchildsemi.com MC79XX/MC79XXA/LM79XX 3-Terminal 1A Negative Voltage Regulator Features • Output Current in Excess of 1A • Output Voltages of -5, -6, -8 , -9, -10, -12, -15, -18 and 24V • Internal Thermal Overload Protection • Short Circuit Protection • Output Transistor Safe Operating Area Compensation Description The MC79XX / MC79XXA/ LM79XX series of three terminal negative regulators are available in TO-220 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. TO-220 Vin 1 1. GND 2. Input 3. Output Internal Block Digram GND R1 VOLTAGE REFERENCE R2 Output Out + Q1 Q2 PROTECTION CI [ ... ]

LM7905 PDF Datasheet Download