How Does Kirchoff’s Voltage Law Apply to Supernodes in Circuit Analysis?

[pekpek]

Hello All,

I am trying to teach myself basic EE. The textbook I am using gave the following example:

1. Find I_S2. Diagram is attached.
Given:
I_S1 = 2A
I₂ = 3A
I₃ = 2A
I₄ = 1A
I₅ = 0A

The answer in the textbook is 1A.

My Method using KCF:
I_S1 + I_S2 - I₂- I₃ - I₄ -I₅ = 0

Substituting the numbers I get: 2 + I_S2 - 3 - 2 - 1 = 0; I_S2 = 4A

I am not sure where I am going wrong here.

Thanks for any insight!

 

[NascentOxygen]

At the junction of R1 and R2 applying KCL you see:
Is1 + Is2 = I2

Voila!

 

[NascentOxygen]

If you look at the equation for the supernode, it won't involve I_S2
current in = current out

I_s1 = I₃ + I₅

Good luck with your studies.

 

[pekpek]

Ahhh. Thanks NascentOxygen!