Power chords are about the simplest chords to play – so simple the experts don’t really consider them chords at all.
They’re made up of just two notes: the root and the fifth (which is why you’ll often see them referred to as C5, D5 etc). You can find the fifth of any note by going up seven frets. For example, the C power chord (C5) is made up of C and, seven frets higher, G. Which is just the bottom two strings open.
You can create power chords all the way up the neck by playing the C and G strings at the same fret. So, playing the G and C strings at the fifth fret will give you an F5 chord.
You can beef the power chords up by doubling the notes on other strings e.g. the C and G notes of the C5 chord can also be found on the third fret of the E and A strings giving you this:
There are plenty of other ways to play power chords too. Here’s a list:
Make sure you don’t play the strings that have an ‘x’ at the top of them. For the A#5 and B5 chords, you have to stop the C string ringing by either resting the tip of your index finger or the underside of your ring finger (of your fretting hand) against it.