In the original drawing, all voltage sources are short-circuited and all current sources are open-circuited, so the equivalent internal resistance of the power supply can be obtained.

RS = 5//6ω= 2.727ω

Then the current source and voltage source are equivalently transformed, and the original picture (a) is transformed into the picture (f).

The equivalent electromotive force can be obtained from figure (f)

E = (5/11) x3v =1.364v, with positive and negative polarity.