## 4 Methodology  
In stage 1, the problem description is defined based on the collected knowledge of the topic. A literature review of the topic is provided. The scope of the study and the relevant aspects are determined in stage 2. The non-intentional emission measurements have been examined under normal operating conditions of the selected individual nonlinear loads with different technical specifications in a laboratory environment located at the Department of Electrical Engineering Fundamentals of Wroclaw University of Science and Technology. The experiment setup includes:  
* KIKUSUI PCR 500 LA programable generator with regulated voltage level whose task is to supply the equipment under test (EUT) without disturbances coming from the public power system network;
* LISN Rohde & Schwarz HM6050-2 artificial network, whose task is to match the impedance of the supply network and the tested device;
* FLUKE 435 Power Quality Analyzer (possible to analyze signals up to 5 kHz);
* Tektronix RSA306B Real-Time Spectrum Analyzer (possible to analyze signals from 9 kHz to 6.2 GHz);
* Voltmeter to monitor the value of the supply voltage at the terminals of the tested device;
* Lighting fixture in which the tested lamps are placed. The diagrams of the prepared test setups for the research are shown in Figure 1.  
Table 1 shows the technical specifications, measured power factor (PF), classification, name of the model and manufacturer of the used EUT. According to EN61000-3-2 standard [16] the devices are classified in class C which is dedicated to lighting sources. For Class C equipment the standard allows specification of fundamental current and power factor by the manufacturer. Lighting equipment can broadly be classified into three categories depending on the type of power factor correction (PFC): passive, active and no-PFC  
Figure 1: Diagram of the experiment setup: (**a**) intended for measurements in the frequency range up to 2 kHz; (**b**) intended for measurements in the frequency range from 9 to 150 kHz. topology. It influences the efficiency of the device. To highlight the features of the passive or active topologies Figure 2 represents a comparison of the current waveform of investigated LED as well as CFL. The real power factor was obtained by measurements. Information about the EUT including detailed specifications, topologies and schematics can be obtained from manufacturers at request. The paper intends to provide data based on measurements in laboratory conditions. Simulation tests using a digital model of the EUT (digital twin) can be used as the augmentation of the research, but they are not included in the scope of the paper. Each lamp is turned on five minutes before taking measurements to stabilize the thermal conditions of the power supply system in the lamp. In all cases, the examined object is supplied with sinusoidal voltage from the KIKUSUI PCR 500 LA generator. To conduct measurements up to 2 kHz, the class A PQ analyzer FLUKE 435 (with the implemented method of spectrum determination following EN61000-4-7 standard [17]) is used, including the associated equipment such as 5 A precision current \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Lighting** & **Nominal** & **Nominal** & **Power Factor** & \multicolumn{2}{c}{**Class**} & \\
**Source** & **Power [W]** & **Voltage [V]** & **[-]** & **According to** & **Manufacturer/Model** \\  & & & & & EN61000-3-2 [16] & \\ \hline LED & 7 & 220–240 & 0.85 & C & Blitzmann/BLZ-DL01-7W \\ LED & 8 & 220–240 & 0.92 & C & Blitzmann/BLZ-DL-CC-8W \\ CFL & 20 & 220–240 & 0.6 & C & Osram/D STICK 20W \\ \hline \hline \end{tabular}
\end{table} 
Table 1: List of equipment under test (EUT). Figure 2: Current waveform (red) under nominal voltage supply (blue) for investigated lighting equipment: (**a**) CFL 20 W lamp; (**b**) LED 7 W lamp; (**c**) LED 8 W lamp. clamps Fluke I5s. The obtained data are analyzed using the manufacturer's PC software (V3.34.1).