The effect of acceptors motion on the ac electronic (electron/hole) I-el-V relations in mixed ionic electronic semiconductors devices, metal1 vertical bar MIEC vertical bar metal2, with material blocking electrodes, are discussed. The motion of acceptors results in hysteresis, peaks, negative resistance and quasi switching. The impact of the motion of the acceptors on the system properties is pointed out. (C) 2012 Elsevier B.V. All rights reserved.