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I am doing a nodal analysis of this circuit.

enter image description here

I have found that \$ V_A = 10 V \$ and \$ V_B = -20 V \$ is it possible to have a situation like that? I mean a difference in potential between terminals of a current source?

I have found \$ i_{R1} = 0 A \$ and \$ i_{R2} = 2 A \$

If that is true there is a difference in potential of 30V on the current source.

If all this is true, the current source is the one driving the circuit, R1 and the voltage source V1 are not having any effect. No current circulating from V1/R1.

Is this calculation wrong?

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  • \$\begingroup\$ Imagine a circuit with just a current source and a resistor, say 1 A and 1 ohm. How could the current source drive 1 A through the resistor except by producing 1 V across it? \$\endgroup\$ – The Photon Sep 15 '18 at 19:45
  • \$\begingroup\$ ok but it would be 1V across the resistor not across the current source, right? \$\endgroup\$ – SpaceDog Sep 15 '18 at 19:46
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    \$\begingroup\$ If you just have the resistor and the current source forming a loop, the same two nodes are across the resistor as across the current source. So if there's a voltage across the resistor, there must also be a voltage across the current source. \$\endgroup\$ – The Photon Sep 15 '18 at 19:47
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Yes, it is possible to have a non-zero voltage across an ideal current source. The voltage may be positive or negative, and a current source may either absorb power or provide power in a circuit.

Likewise, an ideal voltage source may have positive, negative or zero current.

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A current source will adjust the voltage across itself as needed to produce the specified current.

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