I am presenting augmented chords as triads that are formed by playing a major chord, then raising the top key one half-step. I have picked spellings that I find most easy to read.
However, augmented chords split an octave into three equal parts. Because of our notational system, it is very hard to see this without playing them and counting the number of keys that are skipped between the three keys that are pressed and form the chords. I have added color to show the augmented chords at the end of each measure of each line are really all using the same keys.
F aug = F A C#, A aug = A C# E#, Db aug = Db F A. They all look different because of spelling, but by spelling them enharmonically, we can see that they are really the same.
- A aug could be written enharmonically as A C# F.
- Db aug could be written enharmonically as C# F A.
Fine points, for those of you who are more advanced: We say that F aug, A aug and Db aug are “enharmonically equivalent”. In other words, they look different, but they sound the same.
I hesitate to call augmented chords “triads”, since they so often do not appear as three lines or three spaces in a row. Their spelling is actually determined by what chords preceed them and follow them.