## 1 Introduction  
Nowadays, apart from traditional bulb lamps, all lighting technology equipment and accessories are subject to the EMC Directive 2014/30/EC [1]. Going back two decades, the primary light sources of the time were gassed, halogen, and incandescent light sources. The second group consisted of discharge (luminescent) lamps, i.e., fluorescent lamps--fluorescent tubes, high-pressure mercury vapour lamps, and high-pressure and low-pressure sodium lamps. The third group of sources are incandescent-luminescent lamps, i.e., mercury vapour, xenon, and arc lamps. Today, significant technological advances in the production of semiconductor light sources have led to LEDs being used as full-fledged light sources. The increasing emission powers of these sources have allowed LEDs to be used in both outdoor and indoor general lighting, the automotive industry, large LCDs, decorative and architectural lighting, and traffic signalling. The significant advantages of LED lamps are their exceptional durability of up to 100,000 h of reliable operation and energy efficiency resulting from the use of modern SMD-type, light-emitting diode LEDs. The widespread use of LEDs in lighting technology is made possible by the high luminous efficacy of white LEDs. Currently, LEDs with efficiencies in excess of 200 lm/W are commercially available. LED lamps based on them have efficiencies in excess of 100 lm/W [2]. They are usually powered by direct current, so there is no flickering or pulsating effect, and they do not emit ultraviolet radiation. They do not contain mercury in their construction. LED drivers have high efficiency (\(\eta\) > 0.95 and even 0.98), and overload and thermal protection are included. The modern modules are compatible with intelligent lighting systems in buildings. Among the number of the abovementioned advantages, modern LED lamps also have disadvantages. From the point of view of electromagnetic compatibility, a significant problem with LED lamps is their generation of electromagnetic disturbances. This problem was not present in the case of classic incandescent lamps. The generation of disturbance is a consequence of DC/DC converter circuits. Electronic power supplies, which are an integral part of an LED lamp, are used for this purpose. They range from simple converters without a transformer through power supplies containing specialised current stabilisers to more advanced constructions with AC/DC and DC/DC converter circuits [3]. Each LED requires a stable constant value of voltage and a DC to operate properly regardless of whether the LED and its circuits are powered from a DC voltage source or the 110 or 230 V mains. In order to ensure a stable value of the current flowing through the LEDs in modern LED lamps, current stabilisers of the direct AC driver type are commonly used as AC/DC and DC/DC converters in various configurations depending on the power source and the layout of the LEDs being powered. In the case of a power supply circuit with a direct AC driver stabiliser, the mains voltage is rectified by a Greatz bridge and smoothed by an electrolytic capacitor connected to the bridge output. At the output of the rectifier, a DC voltage is obtained which directly supplies the LEDs, usually connected in one or two branches in series (applying to the lamp power). The role of the direct AC driver current stabiliser is to maintain a constant value of the current supplying the LEDs irrespective of fluctuations in the mains voltage. In the case of AC/DC converters, the mains voltage is converted to DC voltage in the first phase and then converted to a voltage with a value adapted to the layout of the LEDs being powered in the second phase. In the case of LED lamps powered from a DC source, the supply voltage is converted in the DC/DC converter from the value of the supply source to the voltage required to power the LEDs. Each converter, whether AC/DC or DC/DC, must ensure that the LED supply current is stable regardless of fluctuations and variations in AC or DC voltage [4].