Major chords

Most chords are taken from the scale and each note of the scale can have a chord built upon it. The best way to understand this is to look at an example. Here is the scale of A major:

Figure 1. Notes and intervals of A major scale (Enlarge)

To base a chord on the first note of the scale, take the first note (A) the third note (C#) and the fifth note (E). This creates the chord (triad) of A major.

Major chords consist of a root note, a major third and a (perfect*) fifth. The interval of a major third consists of two tones. Referring to the piano keyboard, you can see that C# is two tones above A, and is the 3rd note in the A major scale. Consequently the interval between A and C# is a major third. E, which is one a half tones above C#, is the fifth note (a fifth) above A. Therefore, A + C# + E gives the chord of A major.

[*Note: A 'perfect fifth' is the fifth note in the major or minor scale. The perfect fifth is so called because it produces a consonant, pleasing, harmony when played with the root note.]

Figure 2. A major triad (Enlarge)

Next: Minor chords