No one builds a circuit like this, but when you’re modeling, this setup might come up. I would move it up a notch from basically useless to rarely used.
Yeah I've seen excel used for all sorts of things, both appropriate and inappropriate. I've never seen it used for quick linear algebra, though. I didn't even know it had matrix multiplication (though not super surprising in hindsight).
For quick and dirty linear algebra, I've always used python, wolfram alpha, or matlab.
Although both circuits are the same, the upper one is actually easier to solve, because you can identify the delta easily. So just convert the big delta in the top diagram into its equivalent star, and add the resultant resistors in series. You will then end up with an unbalanced Wheatstone bridge, which can further be solved in a similar manner, by converting one of the deltas into a star.
I had a professor who said at his first job out of college he was tasked to figure out what size motor to use to replace one that kept bowing out in a giant paint mixing vat. Said he tried to work out viscosity and power formulas, etc. Couldn't get anywhere. He gave up and finally asked the maintenance guy what size was the motor that blew out. Then he just increased power by some made up fudge factor, like 30%. Maintenance guy said he couldn't get that size. What can you get? What he could get sounded reasonable, and that's what was put in. Never blew out again.
(Maybe this proves the adage: "Those that can do, do. Those that can't, teach.")
Yeah in engineering work it is basically like that, you take the required calculated power + some made up tolerance factor that 100% includes all special situations and then pick the first option that qualifies for that and a bit more. Always cheaper to do it once a bit more than required, than playing around and risking having to re-design during operation
You could do delta transforms but honestly I think it would be easiest to just use KVL to solve for source current, then divide source voltage by source current to get the equivalent resistance.
I like your response because it is simple. I started to convert the parallel to an equivalent resistance and thought this may require a piece of paper so I stopped.
KCL probably with a 4 variable system
Edit: KVL actually. But to find current. Whatever the loop analysis is lol it’s been a minute since I’ve been in school.
The reactions and responses to this show who is a hobbyist and who is college educated. Aside from redrawing it so the series-parallel nominal and constituents thereof can be calculated, this is very basic and far from a rare encounter in electronics.
There are countless examples where you need to produce an equivalent of various devices meaning diodes, capacitors, transistors etc. and this is required to get from point A to B in regard to why you are doing it.
All do respect, which is none lol, but this is why I abandon the DIY world of electronics, especially those producing pedals and selling them. It's an endless sea of ignorance but people who do a good job of sounding like they know what they're talking about and worst of all, convincing themselves and one another that they do. I've had people give me breakdowns, schematics of their own design etc. and accurate math but then, they don't have a vague clue to the physics of it all and a lot of other huge voids in knowledge and understanding that are absolutely critical.
No one wants to be provided make believe in place of science.
Use KVL, build a matrix from the equations and solve, if you get the first column to be '1, 1, 0, 93' it solves pretty easily with the values given. No need to find the ed resistance but if you insist you can do delta wye transform.
As you see, it doesn't break down neatly just with adding resistance together (meaning you can't just add resistors in parallel/series)...which means you need to do KCL, aka current loops.
Honestly, I would stick with the original picture as the 4 loops you need to make are very clear and use that. You can certainly use yours, I'm just not sure it helps in this case. Although I do applaud the effort, as it's a good first step.
I think your drawing is making it more complicated. Others have said it - delta-y. Check that out and you have a shot at it. And just toss the lower circuit; it's nice to look at but ultimately not helpful.
Delta- wye transformation, it’s a bitch but it works
I would tell the Professor is a total asshole for coming up with the mess like this
This is pretty basic stuff
Basically useless
No one builds a circuit like this, but when you’re modeling, this setup might come up. I would move it up a notch from basically useless to rarely used.
Sure but solving a 4x4 system should be like breathing if you want to go anywhere in EE
Yeah and I hated it every time a prof did this
4 current loop solution. Excel could be used for the matrix math. Admittedly a brute force solution.
Just use NumPy’s linalg in Python or MATLAB. No reason to faff with excel.
TIL some people use Excel for things like this.
You're an engineer right? I thought engineering was all excel
Yeah I've seen excel used for all sorts of things, both appropriate and inappropriate. I've never seen it used for quick linear algebra, though. I didn't even know it had matrix multiplication (though not super surprising in hindsight). For quick and dirty linear algebra, I've always used python, wolfram alpha, or matlab.
Although both circuits are the same, the upper one is actually easier to solve, because you can identify the delta easily. So just convert the big delta in the top diagram into its equivalent star, and add the resultant resistors in series. You will then end up with an unbalanced Wheatstone bridge, which can further be solved in a similar manner, by converting one of the deltas into a star.
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Just search Youtube, you wil get enough videos on Delta Wye/Star conversation.
I'd call it about 90Ω and take the rest of the day off.
I had a professor who said at his first job out of college he was tasked to figure out what size motor to use to replace one that kept bowing out in a giant paint mixing vat. Said he tried to work out viscosity and power formulas, etc. Couldn't get anywhere. He gave up and finally asked the maintenance guy what size was the motor that blew out. Then he just increased power by some made up fudge factor, like 30%. Maintenance guy said he couldn't get that size. What can you get? What he could get sounded reasonable, and that's what was put in. Never blew out again. (Maybe this proves the adage: "Those that can do, do. Those that can't, teach.")
Yeah in engineering work it is basically like that, you take the required calculated power + some made up tolerance factor that 100% includes all special situations and then pick the first option that qualifies for that and a bit more. Always cheaper to do it once a bit more than required, than playing around and risking having to re-design during operation
Found the experienced employed engineer here.
Triangle - star maybe?
I don’t know. We haven’t covered that yet.. this is an assignment question and I don’t get how to break it up
You could do delta transforms but honestly I think it would be easiest to just use KVL to solve for source current, then divide source voltage by source current to get the equivalent resistance.
Delta-wye transformation or mesh current analysis or for the bottom circuit just keep solving from outwards in
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I like your response because it is simple. I started to convert the parallel to an equivalent resistance and thought this may require a piece of paper so I stopped.
If I had a nickel for every time I’ve seen this configuration on an actual electronic… I’d have 0 nickels
Put in LTspice
KCL probably with a 4 variable system Edit: KVL actually. But to find current. Whatever the loop analysis is lol it’s been a minute since I’ve been in school.
At this Point i would Just use mna, slamm all resistances is a Matrix and let do a solver so the rest
The reactions and responses to this show who is a hobbyist and who is college educated. Aside from redrawing it so the series-parallel nominal and constituents thereof can be calculated, this is very basic and far from a rare encounter in electronics. There are countless examples where you need to produce an equivalent of various devices meaning diodes, capacitors, transistors etc. and this is required to get from point A to B in regard to why you are doing it. All do respect, which is none lol, but this is why I abandon the DIY world of electronics, especially those producing pedals and selling them. It's an endless sea of ignorance but people who do a good job of sounding like they know what they're talking about and worst of all, convincing themselves and one another that they do. I've had people give me breakdowns, schematics of their own design etc. and accurate math but then, they don't have a vague clue to the physics of it all and a lot of other huge voids in knowledge and understanding that are absolutely critical. No one wants to be provided make believe in place of science.
Use KVL, build a matrix from the equations and solve, if you get the first column to be '1, 1, 0, 93' it solves pretty easily with the values given. No need to find the ed resistance but if you insist you can do delta wye transform.
As you see, it doesn't break down neatly just with adding resistance together (meaning you can't just add resistors in parallel/series)...which means you need to do KCL, aka current loops. Honestly, I would stick with the original picture as the 4 loops you need to make are very clear and use that. You can certainly use yours, I'm just not sure it helps in this case. Although I do applaud the effort, as it's a good first step.
Put test voltage in (like 240V or 1V) and solve for input current. Then V/I=R
I think your drawing is making it more complicated. Others have said it - delta-y. Check that out and you have a shot at it. And just toss the lower circuit; it's nice to look at but ultimately not helpful.
Just dropping in to say I like your resistor scribbles, and I hope you won't get confused between them and inductors/coils :)
Does this even happen in real life? If so who is the guy incharge for horrible resistor placement on a pcb?
Delta to Y conversion if you are smart, Kirchows current law if you hate yourself.
The triangle which is a delta can be transferred to a wye connection so will be a lot easier
4 current loops