# Thevenin equivalent with multiple sources circuit

Sorry if I may ask an idiot question, but its gonna be for few hours right now I have spent on this question. I am asked to find out the value of the voltage between points A and B, aka Uab, and I am supposed to use the Thevin equivalent. I found 12.4 ohms for the thevenin resistance, but for that I replaced every sources by the equivalent, and that short circuited the 4ohms resistance on the left, cause of the replaced 20v voltage source. But when it comes to the Thevenin voltage, I dont know what to do, the 2 resistances above are bothering me, do I need to use the Kennely theorem?

Thanks in advance! • Analyze what is happening at the node in the middle, and ask your self you can simplify the circuit any. – Phil G Sep 23 '19 at 21:00
• Hi, thanks but am I allowed to do the Norton and Thevenin equivalents on any source? I mean converting the only current source by a Thevenin one would simplify a lot, right? Thanks in advance! – Jules K. Sep 23 '19 at 21:05
• Yes - find the Thevenin equivalent source resistance of the current source by setting all the other sources to zero. It should be obvious what I'm hinting at then. – Phil G Sep 23 '19 at 21:12

Finally I've got something of interesting. I was told to use the Thevenin theorem between points C and D instead. C is located on the middle node and D under the 10 ohms resistance. I've summed up everything on that picture, the Rth is 0 ohm because the the circuited voltage source gives a wire with 0 ohms along it, and it is in parallel with the two other resistance, right? And for Eth, I knew the voltage between two branches is supposed to be the same, thats why Eth equals 20 volts. Thanks you Phil! 