General Circuit Question

Thread Starter


Joined Oct 20, 2011

So my question is like the figure. It is given that V0 = 2V and asked what Is the independent current is.

I wrote i1, i2, i3 and i4. I took the bottom essential node as ground zero.

Yellow node is 2V, therefore 2V = i4*4, i4 = 0.5A.

Vblue-2V=8*0.5, Vblue=6V, so i3 = 2A.

i2=i3+i4, which means i2 = 2.5 A

Vgreen-6V = 2.5*2, Vgreen = 11V = (12+10)*i1, i1 = 0.5 A

Is = i1 + i2 = 3 A.

Now my questions. :D

1. Did I solve it correctly? I'm not quite sure about some steps.
2. Does the independent current source has a voltage on its own? Because I tried to solve this question with nodal analysis and I couldn't decide what to do with Is.
3. It was just an instict not to write any current flowing to the node a or node b. Is it always the case in the open circuits?
4. Is it an easy question? At first, I couldn't find the appropriate position to start. I said current flowing through 4 ohms is i1 and then I had to call the current through 8 ohms i2, which turned out to be wrong in my final solution. :D How do we decide the best way of determining the unknown currents?

Thank you for any answer in advance. :) I'm not a native speaker, so if you have trouble understanding anything I've written, I'd gladly explain what I really meant.


Joined Feb 17, 2009
AD1. Your answer look good.

AD2 The voltage across the current source is equal 11V.

AD3 Yes if we have a open circuit the current is always equal 0A.

AD4 The only thing you need is experience in solving those type of circuit.