Kirchoff's Rule: How do you determine what direction to draw your loop?

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Homework Help Overview

The discussion revolves around the application of Kirchhoff's Rule, specifically focusing on how to determine the direction for drawing loops in circuit analysis. The original poster expresses confusion regarding the implications of drawing loops in different directions and the resulting signs of current.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants explore the idea that the direction of the loop may not matter as long as consistency is maintained. Questions arise about the meaning of a negative current and whether it indicates an error in the assumed direction of current flow.

Discussion Status

Participants are actively engaging with the original poster's confusion, offering insights about current direction and sign conventions. There is a recognition that the negative current could suggest a misinterpretation of the current's actual path, but no consensus has been reached regarding the correctness of the book's answer versus the original poster's calculations.

Contextual Notes

There is an implied assumption that the problem does not specify a direction for the current, which may contribute to the confusion experienced by the original poster.

jamba88
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Homework Statement


How do you choose which way to draw your loop when using Kirchoff's Rule?

Homework Equations


None

The Attempt at a Solution


I am guessing that it doesn't matter which way you draw your loop as long as you stay consistent with everything. However when doing a problem, I got a negative current as the answer. The book says the same value, but the current is positive not negative like I got.
 
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If you get negative answer for the current, the initial selection of the path of the current is not the actual path of the current. So you have to give the answer by changing the sign of current.
 
Hi jamba88! :smile:
jamba88 said:
I am guessing that it doesn't matter which way you draw your loop as long as you stay consistent with everything. However when doing a problem, I got a negative current as the answer. The book says the same value, but the current is positive not negative like I got.

That's right, it doesn't matter.

hmm :rolleyes: … either the book's answer is wrong, or yours is …

show us what you got. :wink:​
 
More to the point, when you label the current through a component,
you put an arrow on the wire. This simply states your sign convention.
Again it doesn't matter, although we usually try to guess the positive
direction.
(a negative current means current was flowing in the opposite direction).

Did the question specify a direction for the current?
 
Last edited:

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