Monday, 24 August 2015

Contradiction while solving circuit problem!


Translation: Find the supplied power from the 4V Source using meshes method enter image description here


I proposed five equations related with the circuit but I only find contradiction cause I find Rv value fixed. I suspect there should be voltage drops in current sources but I am not sure I think I am doing something conceptually wrong.


Here my calcuations enter image description here


I skipped some steps but I hope you can follow me.



I am currently getting I2=I3 = 0 which makes the first two equations to fix Rv. By my understanding it is a contradiction.


Note: .5Nk is a name for the resistor value (proportional to N), I have just called it Rv.



Answer



Let's set up the mesh equations as you have the schematic drawn up:


0V200I3600I3400(I3I2)V5mA=0V0VRV(I2I1)400(I2I3)VV2400=0V0V+4V500I1+V5mARV(I1I2)=0VI1I3=5mAI2=V2=200I3400=I32


This provides 5 equations and five unknowns: $I_1$, $I_2$, $I_3$, $V_{5\:\text{mA}}$, $V_{V_2\over 400}$.


Note that this includes the fact that there are, in fact, voltage drops across your current sources. Those are just two more variables, as shown.


Solving this yields 5 functions which depend upon $R_V$.




I can't tell you if $I_2=I_3=0\:\text{A}$ without knowing more about $R_V$. And I don't understand $.5\:N\:k$. (Does it mean $500\cdot N$?) So I'm stuck at this point, if you are looking for numerical results that aren't functions of $R_V$ (or N.)





(You can get $I_2=I_3=0\:\text{A}$ if and only if $R_V=300\:\Omega$. For obvious reasons.)


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