Analyze this circuit with 2 sources and 4 resistors

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The discussion revolves around analyzing a circuit with two sources and four resistors, focusing on current flow and the implications of a dependent voltage source labeled "5i." Participants emphasize the need to set up a system of equations using Kirchhoff's Current Law (KCL) and Ohm's Law to determine the actual current paths and voltages at various nodes. The circuit's configuration, particularly the relationship between the 2-ohm and 6-ohm resistors, is debated, with suggestions that the 6-ohm resistor has negligible impact on the overall analysis. The importance of understanding supernodes and the correct application of KCL is highlighted as essential for solving the circuit effectively. The conversation underscores the necessity for participants to demonstrate their analytical efforts to receive further guidance.
  • #31
mkamalzayed said:
Depending on your assumptions
Node v2 does not receive any current
How do I apply the KCL law?
v2 receives i2, i4, i5.
 
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  • #33
mkamalzayed said:
Where????
These currents flows out of v2
View attachment 353471
Look at the diagram in post #15. i2, i4 and i5 are shown.
 
  • #34
i2,i4,i5 flows from v2
There are not currents entering the node v2
 
  • #35
mkamalzayed said:
i2,i4,i5 flows from v2
There are not currents entering the node v2
You are forgetting what BvU said in post #15: "No worries about the directions of the currents: the correct sign will come out in the analysis."

The arrows on the diagram may not be showing the direction of physical current flow. What if i2 has a negative value?
 
  • #36
Proceed like this. First note that the 6 ohm resistor is connected across voltage sources so it has no effect on the values of v1, v2 and v3; remove it--that means i6=0.

Treating v1, v2 and v3 as a supernode means that you don't write 3 KCL equations for each of v1, v2 and v3. Instead you write one KCL equation for the supernode (the supernode being the combination of v1, v2 and v3). That equation expresses the fact that the sum of the currents entering or leaving the supernode sum to zero.

If i6=0, then i=i4 and i3=i5 so the 3 currents i, i2 and i3 are the only currents entering or leaving the supernode. So we have i+i2+i3=0. Can you express that equation using v1,v2,v3 and the values of the 3 resistors?

To finish you'll need two constraint eqations; I'll help you with those.
 
  • #37
mkamalzayed said:
How ?? "5i" is a current not a voltage
BvU said:
The diamond
1730723722591.png
represents a dependent voltage source of 5i Volts, where i is the current through the 2Ω resistor (
1730723903277.png
in the diagram).


You have chosen not to answer any of the questions asked in #14, so why should I bother to answer
mkamalzayed said:
Depending on your assumptions
Node v2 does not receive any current
How do I apply the KCL law?
Before diving into supernodes, you should first come to understand the diagram and why KCL says ##\ \ i_2+i_4+i_5=0\ \ ## (or ##-i_2-i_4-i_5=0##, which is equivalent).



##\ ##
 
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Likes SammyS
  • #38
The OP is on a 10-day vacation from PF for several issues, so I'll go ahead and close this thread for now. It may be reopened after the OP is back if they send me a PM and show me what they understand about this circuit analysis. Thank you to all who have been patiently trying to help this user in this thread.
 

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