IEC 61204-3:2011 specifies electromagnetic compatibility (EMC) requirements for power supply units (PSUs) providing d.c. output(s) with or without auxiliary a.c. output(s), operating from a.c. or d.c. source voltages up to 600 V a.c. or 1 000 V d.c. The main changes with respect to the previous edition are listed below: - Update of the scope to align with IEC 61204-7. - Update of the normative references to the latest editions. - Change of the definitions of environments to align with the latest editions of the applicable normative references. - Revision of the applicability of tests to different power supply technologies. - Revision of the emission limits and requirements to align with the latest editions of the applicable normative references. - Revision of the immunity limits and requirements to align with the latest editions of the applicable normative references. - Clarification of the different classes of PSU.