Kirchoffs Voltage Law Understanding

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SUMMARY

This discussion centers on understanding Kirchhoff's Voltage Law (KVL), which states that the sum of all electromotive forces (emfs) in a closed circuit equals the sum of all voltage drops. The user presented equations based on their mock paper, demonstrating how to apply KVL with specific voltage values. The community emphasized the importance of writing equations that sum to zero and suggested a systematic approach to avoid sign errors. The correct interpretation of arrows in circuit diagrams as indicators of potential changes was also clarified.

PREREQUISITES
  • Understanding of Kirchhoff's Voltage Law (KVL)
  • Basic knowledge of electrical circuits and components
  • Familiarity with voltage, electromotive force (emf), and potential difference
  • Ability to interpret circuit diagrams and symbols
NEXT STEPS
  • Study the application of Kirchhoff's Voltage Law in complex circuits
  • Learn how to analyze circuits using mesh analysis techniques
  • Explore the concept of potential difference in electrical engineering
  • Practice solving circuit problems with varying voltage sources and resistors
USEFUL FOR

Students preparing for assessments in electrical engineering, educators teaching circuit analysis, and anyone seeking to deepen their understanding of Kirchhoff's Voltage Law and its applications in circuit design.

Ryan Walkowski
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<< Mentor Note -- Thread moved as requested >>

I am trying to complete a mock paper for an upcoming assessment. The mock comes with the answers supplied in bold under the question yet I am having trouble understanding how the answers are obtained. I know that the law states that the sum of all emfs equals all the sums of the voltage drops and i have looked at several online articles but they seem to be very complex for what I need to understand. I am hoping someone can explain using the example I have. I am not sure how the arrows play a part in this either

EDIT: After much banging my head i have come up with the following.Can someone comment if this is correct and if there is a more excepted way of writing it out:

ΣV=0
B-E = -2V
E-D = +10V
D-C = -5V

BE+ED+DC = +3
∴ C-B = 3V

And

ΣV=0

B-E = -2
E-F = +8
A-B = 0

BE+EF+AB = +6
∴ F-A = 6V
IMG_6241.jpg
 
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The arrows depict a change in potential, increasing towards the arrow head. So for example, the arrow on the battery in the left bottom corner depicts an 8 V rise in potential across the battery going from node E to node F. Similarly, on the resistor connected from E to B there's a 2 V potential increase.

Kirchhoff's voltage law states that the sum of the potential changes around a closed path is zero.
 
Ive updated what i think is correct! If anyone can confirm
 
Ryan Walkowski said:
Ive updated what i think is correct! If anyone can confirm
Looks okay.
 
Ryan Walkowski said:
I know that the law states that the sum of all emfs equals all the sums of the voltage drops

gneill has already mentioned this but it's far better to think...

gneill said:
the sum of the potential changes around a closed path is zero.

and start by writing equations that sum to zero. For example you wrote..

BE+ED+DC = +3

I find I make fewer mistakes with the signs if I specify where I'm starting and write my equation to sum to zero like this..

Going anticlockwise from B..
BE + ED + DC + CB = 0

and then rearrange it to solve for the unknown CB.
 

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