Calculating the Current in a Two battery Combination Circuit

AI Thread Summary
The discussion focuses on calculating the current I4 through a 1.94Ω resistor in a circuit with two batteries. The relevant equations include Ohm's Law (V=IR) and Kirchhoff's laws for current and voltage. The user initially set up their equations correctly but realized they had mixed up the resistor values for R2 and R3. After correcting this error, they confirmed that the two equations provided were sufficient for solving the problem. The thread highlights the importance of careful attention to detail in circuit analysis.
BornSurvivor
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Homework Statement



For the circuit shown in the figure below, calculate the current I4 through the 1.94Ω resistor.
cutj20104.gif

As shown, R1 = 4.05Ω, R2 = 8.11Ω, R3 = 6.17Ω, R4 = 1.94Ω, I1 = 2.97A and E1 = 12V

Homework Equations


V=IR
ƩI in a junction = ƩI out of a junction
ƩV in a loop = 0

The Attempt at a Solution


I1R1+I1R2 -E1 + I2R3 =0
I1 = I2 + I4
So
I4 =I1 - ((-(I1*R1) - I1R2 + E1)/R3)

I don't have many tries left, so I want to know if my analytical solution is correct, and if I've just been making my error plugging the numbers back in.
 
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Hi BornSurvivor! :smile:
BornSurvivor said:
I1R1+I1R2 -E1 + I2R3 =0
I1 = I2 + I4

looks ok so far

but won't you need an equation involving E2 ? :confused:
 
Nope! Those two equations were all I needed. It turns out I had mixed up the numbers for R2 and R3. :)
 
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