Watch the Black Dog: Ex. 4b online guitar lesson by Andy Aledort from Kings of Rock & Roll Vol. 7: Jimmy Page
In the first half of this excerpt, the phrases are played up in 17th position of A minor pentatonic, phrased in a "free" way that floats around the straight beat; this sequence requires the execution of oblique bends, which means that one note is bent on one string and allowed to ring while another note is played on another, unbent, string.
In bar 9, I bring in a bit of chromaticism (sequences of notes played half steps apart) which offers a nice diversion from minor pentatonic.