Abstract. The problems of investigation of contemporary illuminants characteristics are considered. Particularly the LED lamps of the following trade marks were tested: «Maxus», «Electrum», «Lemaso». Photometric and electrotechnical parameters, stated by the producers, were tested. The investigation revealed that the stated illuminants’ power did not correspond to the actual experimental data, in some cases the 8% exceeding was registered (Lemaso). On the other hand, the actual power of “Maxus” and “Electrum” LED lamps was lower than stated, -22,5 % and -2,35 % accordingly. The low power coefficient is the major drawback of LED lamps in Ukrainian market. Its actual value ranges are 0,4–0,65, whereas its minimal value for a LED lamp of 5-25 Watt power is considered to be not less than 0,8.
Key words: illuminants, illumination, LED lamp, luminous efficacy, power coefficient.