In this article we consider the questions of studying the characteristics of modern light sources on the example of LED lamps (LED). The problem of energy savings gained weighty significance in recent years, particularly in the light. In many developed countries as a way to reduce power consumption the replacement of incandescent lamps to LED is considered. LED are advanced energy efficient lamps, but much of the lamps that are coming on the inner market of Ukraine do not correspond to the declared lighting and electrical parameters. That is why we investigated LED lamps of such brands as «AUKES», «OK», «Iskra», «Lemanso» if they are in accordance with lighting and electrical parameters. The results of the study indicate that among the investigated parties of lamps value for active power of all the producing capacity does not meet the stated on the package. On the basis of experiments we also determined the dependence of illuminance E, Lx of voltage U, V. On the basis of this study we can say that most of LED lamps when changing the voltage in the range of 180 -240 V LED illumination is proportional to approximately 1% ( ± 0,2%) with a change in voltage at 1%. As we have seen from the research the alleged power LED lamps does not match the experimental data, in some cases more than 30% - LED (AUKES). A major drawback of LED, that enter the market in Ukraine is a low power factor, which varies between 0,51-0,63 further reduces technical and economic parameters of power supply and increases electric gates.