Difference between 7th,Minor 7th and Major 7th Chords

Now you may have confusion regarding the 7th, minor 7th and major 7th chords.
The all three chords are different,I have told you in previous section about scales and scales are the building blocks of Chords. Chord itself is made up of scale's 1st,3rd and 5th note.
This prior knowledge is useful in understanding the construction of all the 7th chords.

7th chord construction
'C' major chord is made up of C E G notes of the 'C' major scale,And 'C' minor chord is made up of C D# G. The 3rd is flatted in minor chords.
In the 7th chords we play four notes instead of three , means the notes that we play in the major and minor chords will remain the same but the one more note will added, that note is the 7th note of that particular scale.

'C7' chord

In the 'C7' chord , we play the notes of the 'C' major chord i.e. C E G and one more note which is note 7th of the 'C' major scale i.e. note 'B'. And we will not play the note 'B' but the flat of note 'B' means half step down. The flat of note 'B' is 'A#' or you can say 'Bb' both of these are the same notes, just name are different. So, the notes play in the 'C7' chord is C E G and A#.

Major 7th Chord construction

Above I told you about the 7th chord construction,Major 7th chords and 7th chords has not much difference. In the 7th chord we have to do the flat of the 7th note of the particular scale,But in the major 7th chords there is no need to do the flat of 7th note. In the 'C7' chord the note we play are C E G A#.

But in the 'Cmaj7' chord the note we play are C E G and B.

'Cmaj7' Chord

Minor 7th chords construction

In the Minor 7th chords the notes we play are the three notes of some particular scale. 1st,3rd,5th notes.

And the 7th note of that scale , but we have to do flat of that 7th note. Same as we do with the 7th chord.

In 'C' minor chord the note play are C D# G and in the 'Cmin7' the notes play are C D# G and A#.

Eb and D# both are same, Bb and A# both are same.

Practice the following chord progression and you will find the difference in the sound in each of these chords:

C7///|Cmaj7///|Cmin7///|C7///|Cmin7///:||C7

I hope you now understand the working of these three chords.