If I have a circuit like the one below, is it possible to determine the total resistance with the usual series and parallel analysis? I have been staring at it for a while and cannot see how I might do it because of the resistors on the left and the right. Hints would be appreciated.


simulate this circuit – Schematic created using CircuitLab

  • \$\begingroup\$ I am not trying to be a smart alec. But there are no resistance values in the circuit. In fact, the rectangles have to be assumed to be resistors. Should we assume that all resistors have the same value, which we can call "R" and then solve from there? \$\endgroup\$ – mkeith Aug 26 '18 at 1:47
  • \$\begingroup\$ I think because the circuit is very symmetric, there is probably a trick you can use to analyze it. \$\endgroup\$ – mkeith Aug 26 '18 at 1:57
  • \$\begingroup\$ the question that you posted does not ask what is the equivalent resistance. .... it asks if the resistance can be solved by a particular method. .... it makes no difference what the resistor values are .... the answer would be either yes or no. \$\endgroup\$ – jsotola Aug 26 '18 at 1:59
  • \$\begingroup\$ @mkeith I left the values blank because I want to know how to go about finding the equivalent resistance for a circuit like this in general. If I gave specific values people might think it was a homework question or something \$\endgroup\$ – user1489 Aug 26 '18 at 2:06
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    \$\begingroup\$ It might be helpful to at least give each resistor a reference designator. It is hard to discuss a circuit which does not have reference designators. \$\endgroup\$ – mkeith Aug 26 '18 at 2:23

If by "parallel and series analysis" you mean combining resistors in series and parallel until you have a single resistor then no, you can't use that kind of analysis because there aren't any resistors in series or parallel to combine. I would be inclined to use node voltage analysis myself.

However, other people might prefer other methods of analysis, such as source transformation or delta-wye transformation. I usually just go for a nodal analysis because it is a general technique and I know it will work.

  • \$\begingroup\$ Thanks. I will try that then. Also isn't delta-wye only useful when the resistors are in a triangle? I thought about trying that but here there are only quadrilaterals \$\endgroup\$ – user1489 Aug 26 '18 at 2:12
  • \$\begingroup\$ wye to delta transformation on some of the three-resistor junctions will yield triangles, and parallel resistors that can then be simplified. \$\endgroup\$ – Jasen Aug 26 '18 at 6:50

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