Most times we think of the Power Chord as having the Root on the bottom.

In G, then: 35xxxx

There's another one that has a more modern sound, which puts the 5th on the bottom:

Same key, G: x55xxx

Assume that the bass will be playing the root.

One can also do some fast powerchord changes with this one, as it is just a one-finger barre of two strings. Don't overlook the A string as bottom string for motion in 4ths. If the G is as above, then the IV chord, the C, would be: x55xxx

This one also has a lot of use in blues rhythm guitar work for certain songs, too. While still a Power Chord, it has a "lighter" sound to it.


--Mac