About the F#aug chord
To play F# augmented, use the first shape above. Place your index finger on the 1st fret of the A string, your middle finger on the 2nd fret of the C string, your ring finger on the 2nd fret of the E string, and your pinky finger on the 3rd fret of the G string. Strum all four strings and check that each one rings cleanly.
Root
F#
Quality
Augmented
Notes
F# · A# · C##
How the F#aug chord works
F#
Root(1)
The home note. It gives the chord its name.
A#
Major third(3)
The major-third interval that establishes the chord's major base.
C##
Augmented fifth(♯5)
A raised fifth that expands the triad.