Source: http://www.ests.um5.ac.ma/cours/Dipl%C3%B4me%20Universitaire%20de%20Technologie/G%C3%A9nie%20Electrique%20et%20Informatique%20Industrielle/Semestre%2002/Composants%20de%20puissance/chap1-composants%20de%20puissance.pdf