Full Idea
A is a logical truth (tautology) (|= A) iff it is a semantic consequence of the empty set of premises (φ |= A), that is, every interpretation makes A true.
Gist of Idea
A logical truth or tautology is a logical consequence of the empty set
Source
Herbert B. Enderton (A Mathematical Introduction to Logic (2nd) [2001], 1.3.4)
Book Reference
Enderton,Herbert B.: 'A Mathematical Introduction to Logic' [Academic Press 2001], p.4
A Reaction
So the final column of every line of the truth table will be T.