In recent years, the need for low power electronic circuits like sensors and wireless systems has been considered by many researchers. Excessive weight, limited lifetime of the batteries and also the problem of replacing them, are the main reasons for harvesting energy from ambient vibrations. Among the various sources of environmental energy, mechanical vibrations have gained in popularity due to their availability. Between the different METHODs of ambient vibration energy harvesting, piezoelectric METHOD, is one of the good ways to harvest energy due to the favorable effects of electromechanical coupling. The most common means of harvesting energy from vibrations is a cantilevered beam with one or more piezoelectric layers. In the present paper, electrical energy harvesting from Euler-Bernoulli trapezoidal cantilevered unimorph beam with base excitation using DISTRIBUTED parameter METHOD has been considered. First, equations of motion are analytically obtained and then using Assumed modes METHOD (for rectangular beam), system’s natural frequencies are calculated and output voltage, current and power diagrams are presented. For verifying results, presented voltage, current and power output diagrams for trapezoidal configuration close to rectangular configuration, the results of which are published in references, will be compared. Then, functional PARAMETERS for trapezoidal energy harvester with resistance value changes for energy consumer have been analyzed.