This work presents an analysis of electric current signal in LEDs lamps. Electrical signals are measured in two circuits, one that corresponds to the commercial LEDs lamp connected to AC source and another one incorporating a control system into the LEDs lamp. Such control system works as a power factor correction (PFC) and is designed by using a boost converter and a current controller. Signals are analyzed in terms of frequency-based representations oriented to estimate the power spectral density (PSD). In this study, two approaches are used: Discrete Fourier transform and periodogram. The goal of this work is to show that more complex PSD estimation methods can provide useful information for studying the quality energy in electric power systems, which is comparable with that provided by traditional approaches. In particular, periodogram shows to be a suitable alternative exhibiting meaningful changes along its spectral power plotting when analyzing the circuit without applying PFC. As a result of this work, a set of LEDs lamps characteristics is introduced, including a novel periodicity factor.