# Should the 3A Current Source Be Included in KCL Equations for Nodes a and c?

• princejan7
In summary, the conversation discusses whether the 3A current source should be included when writing a KCL equation for nodes a and c. The conclusion is that it should be included, as it is connected to both nodes. However, the solution also takes into account the current through "2" and the individual wiring of each node. The conversation also emphasizes the importance of using the correct template when asking for help and understanding the concept of nodes and conductors in electrical circuits.
princejan7
http://postimg.org/image/mk8vo32in/

Just wondering whether the 3A from the current source should be included when writing a KCL equation for nodes a and c,
and if yes, why the full 3A? Wouldn't it split up along the way

thanks

KCl is not potassium chloride but some relevant relationship (yes, I know). If you use the template (required by PF rules), you make it easier for helpers to help you. 1. Introduces us to what is asked, 2. helps us help you if you miss some relationship or use the wrong ones and 3. Helps us help you by indicating what you can and can not do and where you get stuck.

Your direct question has a direct answer: No. the 3A isn't entering or exiting point a nor point b. If you smack KCL on the points just above a and b, then it shows up!

BvU said:
KCl is not potassium chloride but some relevant relationship (yes, I know). If you use the template (required by PF rules), you make it easier for helpers to help you. 1. Introduces us to what is asked, 2. helps us help you if you miss some relationship or use the wrong ones and 3. Helps us help you by indicating what you can and can not do and where you get stuck.

Your direct question has a direct answer: No. the 3A isn't entering or exiting point a nor point b. If you smack KCL on the points just above a and b, then it shows up!

http://postimg.org/image/j6jddk8if/

But the solution to the problem treats the 3A as entering both node a and node c? Is it wrong?

Last edited by a moderator:
It's not 'legally' wrong, as long as you take the current through "2" into account. And the j6jddk8if link seems to do so Ok (I didn't try to untangle what V1,2,3, stand for (lazy me, because it's pretty obvious :-); in general answers supplied are pretty decent).

My general impression is that you understand what's going on and how it is dealt with. Am I far off? If so (or if not so) I'm glad to answer further questions.

A node consists of any contiguous network of wiring. So in your diagram, reproduced here, all of the blue highlighted wiring comprises node a, while all of the green highlighted wiring comprises node c. So yes, when writing KCL for either of those nodes you need to include all branches connecting to them, which of course includes the 3 A current source.

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Fully agree. Makes life easier too. Conductors and chunks of wire are ideal conductors in homework assignments. I stand (actually, I sit) corrected.

## 1. What is Kirchhoff's Current Law?

Kirchhoff's Current Law, also known as Kirchhoff's First Law or Kirchhoff's Junction Rule, states that the sum of all currents entering and exiting a junction in a circuit must equal zero.

## 2. How is Kirchhoff's Current Law used in circuit analysis?

Kirchhoff's Current Law is used to determine the unknown currents in a circuit by setting up equations based on the current entering and exiting a junction. These equations can then be solved using algebraic techniques.

## 3. Can Kirchhoff's Current Law be applied to any type of circuit?

Yes, Kirchhoff's Current Law can be applied to any type of circuit, whether it is a series or parallel circuit, or a combination of both. It is a fundamental law in circuit analysis and is used in all types of circuits.

## 4. What are the limitations of Kirchhoff's Current Law?

Kirchhoff's Current Law assumes that the circuit is in a steady state, meaning that the currents and voltages are constant over time. It also assumes that the circuit is a closed loop and that there are no internal sources of current.

## 5. How is Kirchhoff's Current Law related to Kirchhoff's Voltage Law?

Kirchhoff's Current Law and Kirchhoff's Voltage Law are two fundamental laws in circuit analysis. Kirchhoff's Voltage Law states that the sum of all voltages around a closed loop in a circuit must equal zero. These two laws are often used together to analyze complex circuits and determine the unknown currents and voltages.

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