Solving KCD Question: Understanding I1=I2/I1+2

[wencme]

I understand the current divider and generally comprehend what this professor is saying. BUT, I do not understand why to look only at I3 in the top circuit and look at everything except I4 in the bottom example.

I1= I2/I1+2 so looking at I3 makes sense to me in the first example, but it seems that I should also be looking at I3 in the second example.

 

[berkeman]

I understand the current divider and generally comprehend what this professor is saying. BUT, I do not understand why to look only at I3 in the top circuit and look at everything except I4 in the bottom example.

I1= I2/I1+2 so looking at I3 makes sense to me in the first example, but it seems that I should also be looking at I3 in the second example.

Welcome to the PF.

Can you say more about what is going on in this example? Are they demonstrating how to use superposition to solve for the currents in the original circuit?

 

[wencme]

Yes, we are simply finding the currents in the circuit.
I'm just having a hard time understanding how the current divider is being used.