An equivalent circuit is proposed and the viability of a resonant amplifier of the average active electric power of periodic current pulses generated in the load is theoretically substantiated. The amplifier consists of two series active-reactive circuits with a common capacitive energy storage. In the primary circuit, in the voltage resonance mode, it is charged, and the charging voltage exceeds the source voltage by a factor equal to the quality factor of the circuit. At the end of the charge to a predetermined energy level, the capacitance is discharged through the inductance to the active load. The periodicity of the charge and discharge is ensured by the coordinated operation of the switches in the circuit circuits with a given frequency of their synchronous switching. In principle, the proposed amplifier of active electric power consists of a reactive power amplifier (charging circuit) and a reactive power converter into active power of the generated current (dis-charge circuit). The obtained analytical relationships allow one to navigate in the magnitude of the charging voltage on the capacitance, which can be obtained depending on the charge time. Thus, the maximum voltage set by the quality factor of the charging circuit adopted for numerical evaluations requires charging for ~ 0.004 s. However, already 50% of the maximum voltage is reached in a much shorter time ~ 0.0005 s (almost an order of magnitude lower than the charge length to the maximum). The expressions found for the characteristics of the processes in the discharge circuit make it possible to select its parameters in such a way as to provide the highest gain coefficient for the average power of a periodic sequence of current pulses generated in the active load of the amplifier. It is shown that the value of the average electrical power in the load should depend on the ratio of the charge and discharge times, since when the capacitive storage is being charged, the current in the load is zero. It was found that the gain value can exceed the corresponding energy indicator of the power source by an order of magnitude.