  We investigate the origin and evolution of primordial electric and magnetic
fields in the early universe, when the expansion is governed by a cosmological
constant $\Lambda_0$. Using the gravitoelectromagnetic inflationary formalism
with $A_0=0$, we obtain the power of spectrums for large-scale magnetic fields
and the inflaton field fluctuations during inflation. A very important fact is
that our formalism is {\em naturally non-conformally invariant}.
