The fourth basic chord type is the augmented chord. The augmented chord consists of three notes taken from the major scale of the same letter name. These notes are the first (1), third (3) and augmented fifth (5+) of the major scale, so the chord formula for the augmented chord is:
Notice that the augmented chord is simply a major chord with an augmented (sharpened) fifth. Two arpeggio patterns of the A+ chord are shown here.
As the augmented arpeggio consists entirely from consecutive major 3rds piled on top of each other,
e.g., the notes of the A+ are A, C# and F,
A - C# = maj 3rd,
C# - F = maj 3rd,
F - A = maj 3rd,
all inversions have the same pattern.
The augmented chord shape actually has three different names. To understand why this is so, examine the formula for an augmented chord, 1 3 #5. By applying this formula to the respective scales of each note in the scale, it may be seen that A+, C#+ and F+ all contain the same notes, thus the same arpeggio may be used for all three chords.
Example 139 uses the notes of the A, C# and F augmented arpeggio pattern. The symbol X means a bigger stretch between 1st and 4th finger (5 frets).
The following table illustrates that the notes of the A+,C+ and F+ chord are the same.
Because each arpeggio represents three different chords the complete range of augmented chords is covered by using the shape over four frets. The next example refers to the 4th string.
The easiest way to remember the three different augmented names involved in each shape is simply to read off the notes contained when that shape is held, i.e., if the augmented shape is played at the third fret and the individual notes are named (G B Eb) this gives the three names of the augmented chord (G+, B+ and Eb+). Conversely, if you wish to play a given augmented chord (C+) all you need to do is find a C note on any of the four strings, and then play the augmented arpeggio around it (the arpeggio you play will also produce an Ab+ or E+).
Example 140 uses pattern of the augmented arpeggio pattern without the octave moving up the neck. The first note is C, therefore the chord is C+, E+ or G#+.
Example 141 uses pattern of the augmented arpeggio pattern as illustrated moving up the neck. The first note is Ab, therefore the chord is Ab+, C+ or E+.