What a Power Chord Is

In some styles of music, particularly in rock and roll, it's not always necessary to play a big, full sounding chord. Often, especially on an electric guitar, it sometimes sounds best to play two or three note chords. This is when power chords come in handy.

Power chords have been popular since the birth of blues music, but when grunge music started to rise in popularity, many bands chose to use power chords almost exclusively, instead of more "traditional" chords. The power chords we are about to learn are "movable chords", meaning that, unlike the chords we've learned so far, we can move their position up or down the neck, to create different power chords.

The power chord contains only two different notes, the root note, and another note called the "fifth". For this reason, power chords are referred to as "fifth chords" (written C5 or E5, etc). The power chord does NOT contain the note which traditionally tells us whether the chord is major or minor. Thus, a power chord is neither major nor minor. It can be used in a situation where either a major or a minor chord is called for, however. Take a look at this example of a chord progression:

Cmajor - Aminor - Dminor - Gmajor

We could play the above progression with power chords, and we'd play it as follows:

C5 - A5 - D5 - G5

As you begin to play power chords, you'll note that they work well in certain circumstances (in rock music on electric guitars for example), and don't work well in others (eg. in folk songs played on acoustic guitar).

Power chords on the sixth string

Take a look at the diagram on the left... note that you do NOT play the third, second, and first strings. This is important, and if any of these strings ring, the chord just won't sound very good. You'll also notice that the note on the sixth string is circled in red. This is to denote that the note on the sixth string is the root of the chord. This means that, while playing the power chord, whatever note is being held down on the sixth string is the name of the power chord. For example, if the power chord were being played starting on the fifth fret of the sixth string, it would be referred to as an "A power chord", since the note on the fifth fret of the sixth string is A. If the chord were played on the eighth fret, it would be a "C power chord". This is why it is so important to know the names of the notes on the sixth string of the guitar.
Play the chord by placing your first finger on the sixth string of the guitar. Your third (ring) finger should be placed on the fifth string, two frets up from your first finger. Lastly, your fourth (pinky) finger goes on the fourth string, on the same fret as your third finger. Strum the three notes with your pick, making sure that all three notes ring clearly, and that all are of equal volume.

Power chords on the fifth string

If you can play the power chord on the sixth string, this one should be no trouble at all. The shape is exactly the same, only this time, you'll need to be sure you don't play the sixth string. Many guitarists will overcome this problem by lightly touching the tip of their first finger against the sixth string, deadening it so it doesn't ring.
The root of this chord is on the fifth string, so you'll need to know what the notes are on this string in order to know what power chord you're playing. If, for example, you're playing a fifth string power chord on the fifth fret, you are playing a D power chord.