The question is as follows:
My answer is as follows:
However, per the source the answer is:
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\$\begingroup\$ Millman's is good for this but you need to show the working between your first two lines. Maybe some rounding errors can account for the small difference? \$\endgroup\$– Andy akaCommented Jan 9, 2021 at 10:26
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\$\begingroup\$ You keep asking the same question over and over again: "Can I / Should I use this method on a circuit to analyse it", and the answer is always the same: if you've got all the terms you need for that, yes, you can. If it's easy to solve, then yes you should. I don't think you need another answer. \$\endgroup\$– Marcus MüllerCommented Jan 9, 2021 at 11:46
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1\$\begingroup\$ I'm suspicious of your question. Did you really take the time to carefully typeset your equations, even coloring some of the text red? Show us your work. If you got this answer from another source, give us the link. If you can't tell us where you got the answer then I suggest you take your questions elsewhere. \$\endgroup\$– Elliot AldersonCommented Jan 9, 2021 at 13:07
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1\$\begingroup\$ @ElliotAlderson the OP did show his work, and it's correct. It's the source that is wrong and this is a legit question since it ask for confirmation about what is wrong teaching. \$\endgroup\$– Sredni VashtarCommented Jan 9, 2021 at 13:45
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1\$\begingroup\$ @ElliotAlderson the OP took the picture from the website detailed by Sredni Vashtar (see above) and there isn't anything there that I can see that looks like his carefully typeset equations so I think we should give the benefit of the doubt here. \$\endgroup\$– Andy akaCommented Jan 9, 2021 at 13:52
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1 Answer
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Well, if it's of any help, I also get the same numbers as you. I calculated \$V_L\$ to be 4.7646 volts and I got a current magnitude of 1.0654 amps. I didn't bother to calculate the phase angles.
Is Millman's Theorem approach here correct?
Yes it is and I expect that the "formal" answer given has got some rounding errors. They also appear to be calculating \$V_L\$ to be exactly 5 volts and that is a mistake. I'd consider changing your text books if I were you because that's two questions you have delivered where the formal answer is either wrong or dubious.
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3\$\begingroup\$ yes, if you look at the website I linked above, they computed the voltage disregarding the last branch, and then erroneously attached the branch to the 'Millman equivalent circuit'. I get the same results you and the op get. It's the website that messed things up. \$\endgroup\$ Commented Jan 9, 2021 at 13:43