Think about a qube which has resistance of 2 ohms in its each arm. no resistance physically in its diagonals.Now what will be its equvalent resistance.
I have to disagree. Almost all courses use a set of classic problems that have been used by similar courses for decades. Remember, others may have thoroughly plowed the ground in general, but the students taking that course are working on a whole new field (their mind).zamansabbir,
Variations of problems like this have had the hell beaten out of them in this and other forums, besides the WWW. http://www.radioelectronicschool.net/files/downloads/resistor_cube_problem.pdf. If your instructor gave you this problem, it is pretty lame, and covers ground that has been thoroughly plowed before.
Ratch
I get a different result. Your final result is 411.7 ohms, but I get 419.47342.
I made a single digit error when I copied your resistor values into my matrix, so, yes, I didn't proceed with absolute care. The correct final result is 411.733653166Checked by my grandaughter yesterday.
She confirmed it is 411.7 Ohms.
She cheated using LTSpice. Not allowed in the kindergarden.
Quoting myself:
If you proceed carefully, you will arrive to the right result.
From node To node Resistance
1 2 212.785Ω
1 3 402.671Ω
1 4 440.994Ω
1 5 421.633Ω
1 6 354.618Ω
1 7 400.303Ω
As a Chief Officer I was used, in the pre-PC times, to run routinely the moment calculations requiered to know the final trim and mean draft of a vessel. With just a small calculator.I must say, I'm impressed that you did all those Y-Δ and Δ-Y transformations, got them in the right order and made as few errors as you did. You obviously exercised a lot of care.
However, I think it's better to avoid methods that are so cumbersome; they invite error. You can write the admittance matrix for the resistor cube by inspection and then let the computer (I used an HP-50 calculator) do all the number crunching involved in inverting the matrix.
And, about your granddaughter, is she really in kindergarten? She can use spice? She's got an obvious career path.
What calculations are you referring to? Aren't the calculations for this problem the ones that appear on your web page:If I find my calculations (they should be somewhere) I could post them here. Be well.
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