Voltage source/Current source equations.

Thread Starter

Xenon02

Joined Feb 24, 2021
190
Hello !!

I've got a small problem.
I've watched this video and I saw that the author said it is ok to link two voltage source parallel like here :

1656539524276.png

I did some calculationswith superposition theorem and I can't do something like that

1656539779184.png

And the author did the same with current source :

1656539922223.png

Am I incorrect ?
 

Suncalc

Joined Mar 23, 2021
8
Yes. Whoever did the video ignored the source impedance on the sources. This is technically something you should never do. If you are going to perform analysis you must include the source resistances (Rs) before doing transformations.

The author appears to be attempting to illustrate that node voltages and individual branch currents must be single valued. But he's being very sloppy in his presentation.
 

Thread Starter

Xenon02

Joined Feb 24, 2021
190
Yes. Whoever did the video ignored the source impedance on the sources. This is technically something you should never do. If you are going to perform analysis you must include the source resistances (Rs) before doing transformations.

The author appears to be attempting to illustrate that node voltages and individual branch currents must be single valued. But he's being very sloppy in his presentation.
So my analisys is correct for "ideal source" without Rs ? That I can't connect ideal voltage source parallel
I mean we can't connect ideal sources parallel even if they have equal value like in my superposition equations ?

PS.
I believe this picture is also incorrect :

1656545000356.png

Because if we want to have the current I = I1+I2 there must be a connection like this :

1656545065522.png

If it's not connected like the one I've showed.
Then here the current is equal 0 but it's not :

1656545202885.png
 

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