The A minor triad follows the standard formula for all minor triads. This means you take the 1st, 3rd and 5th notes from the related natural minor scale (obviously in this case A natural minor).

So if you look at the notes in the A natural minor scale
A B C D E F G A

So from this scale the 1st, 3rd and 5th notes are A, C and E which gives you

5th string  open = A
4th string 2nd fret = E
3rd string 2nd fret = A
2nd string 1st fret = C
1st string open = E

As with the C Major scale last month, some notes are doubled. 

Once you know the notes in the triad then you can figure out where else on the guitar you can play the same chord. Like this.

6th string 5th fret = A (same note as the open 5th string)
5th string 7th fret = E
4th string 7th fret = A
3rd string 5th fret = C
2nd string 5th fret = E
1st string 5th fret = A

Which is the standard 'E' shape bar chord version of A minor. 

Following on from last months C Major the A Natural Minor scale is another easy scale to remember in terms of notes.

As the C Major scale is a scale with no sharps or flats, so is A Natural Minor and is what is known as the 'Relative Minor' to C Major. It is made up from the following notes:

A B C D E F G A

If you look at the notes in this scale against the notes in the C Major scale (C D E F G A B C) you can see that the relative minor scale begins on the 6th note of the major scale.
(1 = C, 2 = D, 3 = E, 4 = F, 5 = G and 6 = A).

This relationship is standard for all natural minor scales, with all natural minor scales having a related major scale and all major scales having a relative minor scale.

As with last months scale this scale also has a scale spelling.

As a natural minor scale it's scale spelling is:

1 2 b3 4 5 b6 b7 8

The important point to remember with scale spellings is that they are all number in relation to the major scale. Have a look at the thread on Scale spelling for more on this.

One of the items you'll find in this blog and also in the RGT syllabus is the concept of scale spelling. In practise this is something that can be a bit confusing so I thought I'd try and explain it here using examples.

So the first thing is 'What is a scale spelling'. Simply put this is just giving each note in the scale a number. Each major scale has 8 notes (including the octave, more on what an octave is to follow), so the numbers run from 1 to 8.

The two main things to bear in mind with scale spellings is that they are all intended to show how the scale you are looking at relates to a major scale and secondly, that just because a scale spelling might contain a flattened note it doesn't mean that the actual note you play is a flattened note (see told you it could be confusing).

Let's use the C Major, A Major and C Natural Minor, A Natural minor scales to explain this.

If you read last months scale of the month (C Major) you'll see that the scale spelling for major scales is 1 2 3 4 5 6 7 8. This means that the notes in the C Major scale are
1 = C, 2 = D, 3 = E, 4 = F, 5 = G, 6 = A, 7 = B, 8 = C
as they say in the meerkat add 'simples'.

Now the scale spelling for a Natural minor scale is
1 2 b3 4 5 b6 b7 8.
So if you take the 3rd, 6th and 7th notes of the C Major scale (E, A and B) and take them down a fret on your guitar So the E becomes Eb, A becomes Ab and B becomes Bb. Which means the notes for a C Natural minor scale are
C, D, Eb, F, G Ab, Bb and C with the scale spelling underneath.
1    2   b3  4  5   b6   b7         8

So what's confusing about that. Not a lot really until you apply the same logic so something like the A Major and A Natural minor scales.

The key signature for the A Major scale is 3 sharps so whilst the scale spelling remains the same some of the notes are sharpened thus.
1 = A, 2 = B, 3 = C#, 4 = D, 5 = E, 6 = F#, 7 = G#, 8 = A.

So where does the confusion come in?. Well if you take the scale spelling for the natural minor scale again to this scale you'll have to again take those notes down by a fret on your guitar. BUT whilst you're flattening a note (remember is b3, b6, b7) the notes that you're applying that to are already sharpened by the key signature (C#, F# and G#.) so what you end up with is that the C# becomes a C (not a Cb), the F# becomes a F (not a Fb), and the G# becomes a G (not a Gb), so the notes in the A Natural minor scale are
A B   C  D E   F   G  A, again with the scale spelling underneath.
1  2  b3 4  5 b6 b7 8

Once you get your head around this you can then use the same logic to work out any scale from it's scale spelling as long as you know the key signature of the major scale your applying it to.

More on key signatures later.