We have found that small long-type magnetoelectric (ME) laminate composites of magnetostrictive Tb1-xDyxFe2-y and piezoelectric Pb(Zr,Ti)O-3 are quite sensitive to small dc magnetic field (H-dc) variations, when driven by a constant ac magnetic field. The sensitivity limit is H-dc < 10(-3) Oe (10(-7) Tesla) using a constant amplitude low frequencies drive, and H-dc < 10(-4) Oe (10(-8) Tesla) under resonant drive. In addition, an unusual ME switching effect-a 180 degrees phase shift-was observed, in response to changes in the sign of a small H-dc. (c) 2006 American Institute of Physics.