Solving Current in a Circuit with Kirchhoff's Rules

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SUMMARY

This discussion focuses on solving current in a circuit using Kirchhoff's Rules, specifically addressing a circuit with a 14.4Ω resistor and an 8.6V battery. The application of Kirchhoff's voltage law yields a current of 1.74A through the 14.4Ω resistor and a current of -0.71A through the 23.2Ω resistor. The negative sign indicates that the current flows opposite to the assumed direction. The calculations are confirmed as correct, with the only noted issue being the labeling of currents in the circuit diagram.

PREREQUISITES
  • Understanding of Kirchhoff's Junction Rule
  • Familiarity with Kirchhoff's Voltage Law
  • Basic knowledge of circuit components (resistors, batteries)
  • Ability to solve linear equations
NEXT STEPS
  • Study advanced applications of Kirchhoff's Laws in complex circuits
  • Learn about circuit simulation tools like LTspice or Multisim
  • Explore the concept of internal resistance in batteries
  • Investigate the impact of resistor combinations on circuit behavior
USEFUL FOR

Students studying electrical engineering, physics enthusiasts, and anyone looking to deepen their understanding of circuit analysis using Kirchhoff's Rules.

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Homework Statement



The currents are flowing in the direction indicated by the arrows. A negative current denotes flow opposite to the direction of the arrow. Assume the batteries have zero internal resistance.

http://img123.imageshack.us/img123/2045/599c898aa10950d7027807dyc7.th.jpg

A) Find the current through the 14.4Ω resistor and the 8.6 V battery at the top of the circuit. Answer in units of A.
B) Find the current through the 23.2 Ω resistor in the center of the circuit. Answer in units of A.

Homework Equations


Kirchhoff's Junction and Loop Rules


The Attempt at a Solution




By applying the Kirchhoff's voltage law to the above loop I get
8.6V - (23.2Ω)I1 - (14.4Ω)I = 0

23.2I1 + 14.4I = 8.6 ........(1)

Applying the Kirchhoff's voltage law to the down loop I get

16.4V + (23.2Ω)I1 = 0

I1 = - 0.71A

Substitute this value in the eq(1)

8.6V + (23.2)(0.71) = 14.4I

I = 1.74A

Therefore the current passes through the battery 8.6V and the resistance 14.4Ω is 1.74A

For Part B, I thought that the current would be equal to I1 which I already solved for in Part A, so the current would be -0.71 A.

I've pretty much worked everything out but I was hoping if someone could tell me if I was doing it right or not. I'm not too confident when it comes to these problems. Any comments would be very helpful. Thanks!
 
Last edited by a moderator:
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Everything looks good, except for the picture, where all the currents are labeled by the same label (I). The answers are both correct.
 

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