Recent developments in the design of low-power circuits have allowed Energy Harvesting (EH) systems to feed electronic circuits that execute complex processes, permitting that such systems play an important role in different application areas (e.g. Wireless Sensor Networks (WSN), biomedical devices, Internet of things (IoT), among others). Due to the low power output presented by these systems (in the range of #x03BC;W to mW), the reduction of any potential losses presented in the circuits that form the EH system is a mayor issue; therefore, a careful selection of the circuits and its components may improve the performance. In this work, a comparison of various rectifier circuits found in the EH literature is presented. Based on the operation of each rectifier, the modeling of the power losses of each circuit will be introduced. Finally, the simulation results of the considered circuits are presented with the aim to measure parameters, like the efficiency, and perform a quantitative comparison.