A Study of Inexpensive Stable Conducted/Radiated Emission Sources Suitable for the EMC Directives

In this paper, a single-phase stable and inexpensive switching power supply (SPS), which gives three values as called for in the US and EU standards, when spectrum analyzer (SA) operating in peak, quasi-peak and average detecting modes, is identified. In order to have a usable stable source, a warm up time for the SPS should be more than 15 minutes. Several conducted and radiated measurements at four selected frequencies have been repeated in a month span. It is determined that an amplitude variation of plusmn1.0 dB can be achieved. For radiated emissions, an in-house printed circuit board employing a simple logic is designed and built for peak detection mode. The worst amplitude stabilities are within plusmn2.07 dB for vertical polarizations. The inter-laboratory correlation is performed only on conducted emission. The variation was within plusmn3 dB for the three modes of detection