With the 78XX family IC's you can get regulated dc voltage at the output . The last two digits of the IC represents the IC's output voltage , for example: in 7805 the last two digit is 05 which means the IC will give 5v regulated output .These are easy to use and cheap but are very inefficient as the input goes higher,which the higher the input voltage the lower is their effficiency and requires heatsink .But there are certain norms in using this IC which you can get to know with the video attached.
With the video attached surely you can get a detailed view on 7805 IC.
Step 1: Basics
The basic knowledge you need to have before start using 7805 IC is listed in the picture.