The mechanical behavior of a bimorph piezoelectric micro cantilever exposed to harmonic base excitation is investigated. The governing motion equation coupled with the equation of the output electrical circuit is discretized using Galerkin method and numerically integrated over the time. Two different types of output circuits including parallel and series connections are examined and the most effective output circuit from the power delivery point of view on the domain of the governing parameters is introduced. The energy conservation is examined by comparing the input and harvested energies. It is concluded that the energy harvesting in the absence of mechanical damping resembles the behavior of a damped mechanical oscillator due to the exponential attenuation of the motion amplitude. It is shown that the output power in terms of the load resistance of the output circuit, exhibits Lorenzian behavior revealing the multi factorial dependency of the power on the governing parameters. The effect of load resistance and the effective piezoelectric stress constant on the equivalent damping ratio is investigated. Subjected to harmonic base excitation, the steady state voltage, current and power responses are presented. The results are presented for various piezoelectric materials and on the plane of load resistance and effective piezoelectric stress constant, the output power delivery as well as the equivalent non dimensional damping coefficient is determined. (C) 2015 Elsevier Ltd. All rights reserved.