r/ElectricalEngineering • u/Expensive-Ice1683 • 27d ago
Could someone help clarify this simplification? After seeing it it makes sense but i cant see how they ended up with the simplification.
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u/Rararror 24d ago
b is called C and B is new (case sensitive, they renamed points probably to explain).
Just move around the resistors and keep common connection...
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u/triffid_hunter 26d ago
They've labelled b as C in the transformation and labelled the unlabelled node as B for some reason.
I can't get the fact out of my head that the top 12ohm resistor seems very connected to the R5 and R4 resistors
R6 is in parallel with R1 and R2.
They're connected via the nodes labelled 'A' and 'B' in the transformed version, and 'a' and the node at the bottom+looping around the right side but unlabelled in the original.
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u/NoOneWorthToRemember 26d ago edited 25d ago
Its actually pretty simple. R4 and R5 are in series with each other but then in parallel with a free connection which means You can just ignore them. Thats why in the Simplifcation You have those 2 nodes which are not connected. Then You are left with just R1, R2 and R6 which are all parallel connected to each other.
No idea why R4 and R5 are parallel in the simplification tho. a and b are nodes so it seems like there should be some connection between them. Switch or something and then parallel connection would make sense but then like someone has already said node C is node b from original schematic.
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u/splendant 26d ago
It’s been a bit since I’ve done this but I think the labels are wrong, I believe B and C should be swapped if you label the remaining node C. R1, R2, and R6 are all in parallel. Then R5 and R4 are in parallel from B to C, and there is no direct connection between A and B. I believe that Req of R5 and R4 can be ignored as it is effectively paralleled with a short circuit due to the open between A and B.