Under 621.3 is classed information about electrical engineering, including electronics, and the fundamental applications of electrical engineering. Particular applications of electrical engineering are classed under various other sections (see related subjects below). The theoretical aspects of electricity, magnetism and electromagnetism and their measurement are found under 537.
BS 1000[621.3]:1989 history
1989BS 1000[621.3]:1989 Universal Decimal Classification - English full edition - Electrical engineering