Kirchhoff's law: Find the current I3 through the Amp meter

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SUMMARY

The discussion focuses on applying Kirchhoff's laws to find the current I3 through an Amp meter in a circuit. The user initially formulated equations for the upper and lower loops but later corrected them to -14 + 3.3(I1) + 3.4(I3) + 2(I1) = 0 for the upper loop and -16 + 5.3(I2) - 3.4(I3) + 2.9(I2) = 0 for the lower loop. After solving, the user calculated I3 to be 0.336 A, I1 to be 2.43 A, and I2 to be 2.09 A. The results were verified, but it was noted that rounding I1 to 2.426 A could yield a more accurate result.

PREREQUISITES
  • Understanding of Kirchhoff's Voltage Law (KVL)
  • Familiarity with circuit analysis techniques
  • Ability to manipulate algebraic equations
  • Knowledge of current and voltage units (Amperes and Volts)
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  • Investigate the impact of rounding errors in circuit calculations
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Electrical engineering students, circuit designers, and anyone involved in analyzing and solving electrical circuits using Kirchhoff's laws.

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Homework Statement
Find the current I3,I2, and I1 through the Amp meter.
Answer in units of A.
Relevant Equations
I used the Junction Rule - I3= I1+I2
I separated the circuit into parts- upper and lower

For the upper loop I wrote: -14-2I1-3.4I3-I2 = 0
For the lower loop I wrote 16-2.9I2+3.4I3-5.4I2 = 0

I solved for I1 and I2 separately and plugged it into the junction rule and solved for I3.

I may have got it wrong because of the incorporation of the extra resistor in the upper loop and lower loop and solved incorrectly.

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Correction for the problem after i found I3 correctly now.

The correct equation is now -14+3.3(I1)+3.4(I3)+2(I1)= 0 for the upper loop and
-16+5.3(I2)-3.4(I3)+2.9(I2) = 0 for the bottom loop. Once you separate variables, I2 = stuff and I1 = stuff, you can use the junction rule I1 = I2+I3 and rearrange to get I1-I2=I3. Plug it in and you should get I3 = 0.336A
 
Use I3 to get I2 and I1 since you have separate equations for them already -

I1 = -3.4(I3)+14/5.3 and I2 = 3.4(I3) +16/ 8.2

I1 = 2.43 A , I2 = 2.09 A
 
If anyone else sees this, can you verify that my explanation is correct since I was able to get the correct answers on my own.
 
## \text { The explanation is correct, but the result can be more accurate. } ##

## 3,3 \Omega \cdot 2,43 A + ( - 14 ) V + 2 \Omega \cdot 2,43 A + 3,4 \Omega \cdot 0,336 A = ##
## = 8,0058 V – 14 V + 4,852 V + 1,1424 V = ##
## = 0,0214 V \neq 0 V ##
## \text { It is hard to say that Kirchhoff Voltage Law is satisfied for the upper loop because it is hard to say that } 0,0214 V \text { is equal to } 0 V \text { . } ##
## \text { The more accurate result can be got rounding the value of } I _ 1 \text { to } 2,426 A \text { instead of } 2,43 A \text { . } ##
## \text { Values of } I _ 2 \text { , which is } 2,090 A \text { , and } I _ 3 \text { , which is } 0,336 A \text { , can remain the same. } ##
 

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