There are 4 triads. Major, minor, augmented, and diminished.

Let's examine the C maj chord: C, E, G.

flowchart TD

  

subgraph Z[" "]

direction LR
classDef highlight stroke:#fed7e2
classDef grey stroke:#17171f
W[C]:::highlight ~~~ O[E]:::highlight
O[E]:::highlight ~~~ U[G]:::highlight

end

Z

Chords are built from 3rds. This means we stack notes on top of each other using intervals of either a minor 3rd or a major 3rd. The most basic chord is a triad, which consists of 3 notes.

If we look at the intervals C to E (4 half steps), and then E to G (3 half steps), we can see that we have a major 3rd with a minor 3rd paired after it.

flowchart TD

  

subgraph Z["Maj 3rd"]

direction LR

classDef highlight stroke:#fed7e2
classDef grey stroke:#17171f
W[C]:::highlight ~~~ G[C#]:::grey
G[C#]:::grey ~~~ I[D]:::grey
I[D]:::grey ~~~ A[D#]:::grey
A[D#]:::grey ~~~ O[E]:::highlight


end

  

subgraph ZA["Min 3rd"]

direction LR

Y[E]:::highlight ~~~ U[F]:::grey
U[F]:::grey ~~~ D[F#]:::grey

D[F#]:::grey ~~~ P[G]:::highlight




end

Z ~~~ ZA

The Maj 3rd interval with a Min 3rd on top creates the major triad, so what if we did a minor 3rd with a major 3rd on top? That would give us the notes: C, E♭, and G, which is the C minor triad. There are only 4 possible combinations to be made. Two major 3rd intervals stacked on top of each other will be an augmented triad: C, E and G#. Two minor 3rds together will create a diminished triad: C, E♭, G♭.

flowchart TD

  

subgraph Z[" "]

direction LR
classDef highlight stroke:#fed7e2
classDef grey stroke:#17171f
W[Maj 3rd]:::highlight ~~~| + | G[Min 3rd]
G[Min 3rd] ~~~| = | H(Major Triad):::grey


end

flowchart TD

  

subgraph Z[" "]

direction LR
classDef highlight stroke:#fed7e2
classDef grey stroke:#17171f
W[Min 3rd] ~~~| + | G[Min 3rd]
G[Maj 3rd]:::highlight ~~~| = | H(Minor Triad):::grey


end

flowchart TD

  

subgraph Z[" "]

direction LR
classDef highlight stroke:#fed7e2
classDef grey stroke:#17171f
W[Maj 3rd]:::highlight ~~~| + | G[Maj 3rd]
G[Maj 3rd]:::highlight ~~~| = | H(Augmented Triad):::grey


end

flowchart TD

  

subgraph Z[" "]

direction LR
classDef highlight stroke:#fed7e2
classDef grey stroke:#17171f
W[Min 3rd] ~~~| + | G[Min 3rd]
G[Min 3rd] ~~~| = | H(Diminished Triad):::grey


end