Longitudinal and transversal permanent electric fields generated by an ac current through superconducting Pb and Nb thin strips have been studied as the function of the drive frequency (10(3)< f < 10(8) Hz), temperature, and magnetic field. At low frequencies (f < 10(4) Hz) and below the critical temperature, the superconducting strips behave as one-dimensional rectifiers, whereas for higher drive frequencies (f>10(5) Hz) the rectification becomes two dimensional. The rectification strongly depends on the magnetic field, temperature and ac drive. The unusual dc electric field topology generated by the ac current in the superconducting strips can be explained by a local rectification due the oppositely directed asymmetric edge (Bean-Livingston type) barriers. (c) 2006 American Institute of Physics.