Pentatonic scales are abbreviated forms of regular scales. They only use five notes of a scale, and are more versatile as they work better over most chord changes.
The minor pentatonic scale uses scale degrees 1, 3, 4, 5, 7 of a natural minor scale.
The major pentatonic scale used the scale degrees 1, 2, 3, 5, 6 of a regular scale, demonstrated here with the C Major Pentatonic Scale:
Relative Minor Pentatonic Scales
As with the full scale pattern covered before, the same relationship exists between major pentatonic scales and their relative minor pentatonic scale. All that changes is which note you start on.
By looking at both scales like this you can see that the final note of the major pentatonic scale is the same as the starting note of the relative minor pentatonic. The starting note of the relative minor pentatonic is also just one below the starting note of the major pentatonic.
For the moment let's look at some basic chord progressions and identify the pentatonic scales that fit them. G, D and A are all very common fiddle tune keys, so we'll use those. Note that each scale starts with the root note or tonic of that scale:
Let's make these a little more interesting by changing the order of the notes very slightly, and arranging them into a resolving chord progression in the style of an actual tune:
Key of G:
Key of D:
Key of A:
These patterns can also be moved up and down an octave, which helps to vary them and opens up more possibilities for improvising, so for example in D you could play the following (and note that the Pentatonic Scale for A is the same as E, but played on the G and D string with A as our tonic note):
Now if you add a slide with a blues note, and again rearrange the order of the notes, it starts to sound a bit more like a lick:
As mentioned before, major pentatonic scales have a natural minor equivalent. When using the minor pentatonic scale to solo over a tune's relative minor chord, you can simply use the same notes as the major pentatonic. Here's the same example, but with the Am pentatonic scale included: