IC 7805

Try LM-7805 datasheet, Fairchild, and 78xx in wiki.

There is so much data available about this IC, it may be possible miss it.

Try http://pdf.datasheetcatalog.com/datasheet2/9/0p4t1g1lw0spoo5ukh2s1uxchzky.pdf

and http://pdf.datasheetcatalog.com/datasheet/fairchild/LM7805.pdf

I hope that helps you.

http://www.electrokits.com/Datasheets/IC-7805-datasheet

A linear voltage regulator consists of a voltage reference, a comparator, and an output circuit.

Here is a simple voltage regulator that shows the principle:

The zener voltage reference is D1. The comparator is Q1. When the output voltage drops, Q1 turns on Q2, letting more current through and raising the output voltage. If the output voltage is too high, Q1 turns off Q2, reducing current and lowering the output voltage.

The schematic for the 7805 is more complicated, but you should be able to spot the voltage reference diode (on the left), the comparator circuit (center) and the series pass output circuit (right side) between input and output.

You can try Datasheets360:

http://www.datasheets360.com/search/results?query=7805

http://www.righto.com/2014/09/reverse-engineering-counterfeit-7805.html

There are plenty of raw photos in there for you to literally see how the inside of this chip looks like !

Do understand that each chip maker have their own design, but concept and function of a 78xx remains the same eh!

I find it hard to accept that you spent any appreciable time looking for the answers for yourself. Take this trivial search, for instance:

... which yielded about 16,000,000 results, or this rather more complex effort:

... with 430,000 results.

Did you get the answer you were looking for? If your DC voltage is a little too high, do you know what to do to drop it a little bit without wasting a lot of power in the form of heat?