Source google image: http://1.bp.blogspot.com/–JvdrYrIsII/Ug4f3CIXh6I/AAAAAAAADBE/bRK9VLmV8Is/s1600/2013-08-16+14.11.59.jpg
Schema electrique normalise
Source google image: http://1.bp.blogspot.com/–JvdrYrIsII/Ug4f3CIXh6I/AAAAAAAADBE/bRK9VLmV8Is/s1600/2013-08-16+14.11.59.jpg