Watch the Power Chords online guitar lesson by Jennifer Batten from Rock Sauce for Rhythm Guitar
Power chords are not really chords in the technical sense. A chord needs to have 3 tones; 1, 3, and 5. Power chords have either a 1 (root) and 5 or additional octaves of the same notes. Because there is no 3rd, you don’t know if the chord implies a major or a minor unless your ear tells you, and/or you understand chord scales from the previous segment.