Once you have an understanding of how scales work, it’s time to start understanding how chords are constructed. The basic building block of chords is called a triad, and today we going to be explaining what these are, and how they work.
What Is A Triad?
A triad is a collection of three notes, most often. A root note, a third, and a fifth, though as we will see, this isn’t always the case. In formula form, they are notated the same way as a scale, for example, 1-3-5. Triads are the most basic of chords. For example, If someone is playing an A minor chord, they are playing the notes from the A minor triad, which are A-C-E. A triad is a chord, but a chord is not necessarily a triad. In most sheet music, it is denoted my a capital letter of the root note, an then a symbol that denotes what kind of chord it is. Those will be explained below.
1. Major And Minor Triads
The major triad is made up of the root, the major third, and a perfect fifth. The major chord is notated by just the note, and nothing else.
The minor triad is made up of the root, minor third, and perfect fifth. The minor chord is notated by the note, followed by a lowercase 'm'.
2. Augmented And Diminished Triads
The Augemented Triad is the same as the major triad, but with an augmented fifth instead of a perfect fifth. It is notated by a "+" sign after the root note name. This chord doesn’t show up in the standard diatonic (major and minor) scales.
The Diminished Triad is the same as the minor triad, but with a diminished fifth instead of a perfect fifth. It is notated by a "º" symbol.
These chords don’t come up a lot in most music todays. You will see the diminshed triad occasionally, and it classical or classicly influenced music. The augmented chord is seen sometimes in classical music as well, and occasionally in jazz.
3. Suspended Triads
The Suspended 2nd triad is made up of the root, the major second, and the perfect fifth. It is notated with a ’sus2′ after the root note.
The Suspended 4th triad is made up of the root, the perfect fourth, and the perfect fifth. It is notated with a ’sus4′ after the root note.
Something interesting to note is that these chords are neither major or minor, and can be used as a substitute for both.
Lesson Review
Here is a chart with this information for quick reference.
Triad name Triad formula Notation
Major 1 - 3 - 5 C
Minor 1 - b3 - 5 Cm
Augmented 1 - 3 - #5 C+
Diminished 1 - b3 - b5 Cº
Suspended 2nd 1 - 2 - 5 Csus2
Suspended 4th 1 - 4 - 5 Csus4
/ my profile 
