Triad is a set of three notes which located one from another through thirds (more about intervals here). Let’s consider the four main triads.
Major Triad
Major triad consists of the following intervals:
- major third;
- minor third.
On the picture above shows the C major scale and the triad, consisting of 1, 3 and 5 steps (more about the steps and scales here).
Minor Triad
Minor triad consists of the following intervals:
- minor third;
- major third.
On the picture shows the C minor scale and the triad, consisting of 1, ♭3 and 5 steps.
Minor and major triads are basic, but there are others.
Diminished Triad
Consist of:
- minor third;
- minor third.
Augmented Triad
Consist of:
- major third;
- major third.
On the picture below we see schemes of the all four basic triads:
