Suspended 4th replaces the 3rd with the 4th (1–4–5). It builds tension that classically resolves down to the major 3rd, a staple of rock and gospel.
NotesE · A · B
Formula1 · 4 · 5
Every suspended 4th chord tone across the neck. Solo with these and you spell the chord — that's the difference between running a scale and playing the changes.