In this paper, the operation of a system for stabilized power supply of an active load from a photovoltaic panel via a step-down DC converter without galvanic isolation was analyzed at the experimental level. The voltage regulation of the load was ensured by automatic adjustment of the converter control factor. First, the basic characteristics of photovoltaic modules and the influence of temperature and insolation on the electrical characteristics of a photovoltaic cell are described. The basic characteristics of the step-down DC converter and its characteristic operating modes are listed. Some possibilities of the programmable DC source Magna Power, which can operate in several different operating modes, are also shown. In this paper, the mentioned DC source was used as a photovoltaic panel emulator. A control algorithm was created in the MATLAB Simulink software package and the parameters of the PI regulator were determined. The interface for controlling the experiment in real time was implemented in the ControlDesk software package. A laboratory mock-up of the system with a DS1104 control card (dSpace), an optocoupler as a pulse device for IGBT, and current and voltage sensors is described. The responses of selected system variables to changes in the voltage reference value and changes in insolation and temperature of the photovoltaic panel are shown, as well as the corresponding waveforms in the steady state.