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My question is about MESH and NODE methods, how I choose to use one over the other?

For example if I have this circuit, my professor used the node method, but also a mesh method could be used? Why?

schematic

simulate this circuit – Schematic created using CircuitLab

Known data: \$R1=1,\$ \$R2=1,\$ \$R3=3,\$ \$I1=3,\$ \$I2=8,\$ \$V1=15\$

I'm asked to find all voltages referred to the resistors.

I haven't tried to resolve it with the mesh method, I resolved it only with the node method (alone and then I checked the professor's solution).

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    \$\begingroup\$ Use the one you feel more comfortable with. \$\endgroup\$ – Eugene Sh. Jul 5 '18 at 18:05
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    \$\begingroup\$ I'd probably use superposition. \$\endgroup\$ – Andy aka Jul 5 '18 at 18:11
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    \$\begingroup\$ Only need two simultaneous equations for nodal analysis; mesh analysis needs three. \$\endgroup\$ – Chu Jul 5 '18 at 18:44
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In general you can use either method. The only cases where you would not want to use the mesh method is if the circuit is not planar.

Sometimes you can recognize that a particular circuit will be a bit easier to solve with one method or the other. For the circuit you've given, I can see that if I use the node voltage method and place ground at the bottom, then I get the voltage at one node (15V) by inspection. I also won't need any supernodes. On the other hand, if I use the mesh method I need to make a supermesh around I1...not a big problem but a little more work.

Learning to use the mesh method and the nodal method isn't as much about solving circuit problems like this as it is about becoming very comfortable using Ohm's Law, KCL, and KVL. This leads to a more intuitive understanding of currents and voltages, which is the real goal. That's why instructors often insist that you use a particular method.

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In general I would suggest the nodal method when you're primarily dealing with voltage sources and calculating voltages, and the Mesh method when dealing with current sources and measuring currents. One isn't always superior to another, so do what you're most comfortable with (or obviously involves fewer equations). I typically default to the nodal method.

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