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

  • #1
skibidi
10
0
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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  • #2
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
 
  • #3
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
 
  • #4
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.
 
  • #5
## \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. } ##
 

1. What is Kirchhoff's law?

Kirchhoff's law, also known as Kirchhoff's circuit laws, are two fundamental principles in circuit analysis that explain the behavior of electrical circuits. These laws are used to calculate the current and voltage in a circuit.

2. What are the two laws in Kirchhoff's law?

The two laws in Kirchhoff's law are the Kirchhoff's Current Law (KCL) and the Kirchhoff's Voltage Law (KVL). KCL states that the sum of all currents entering and exiting a node in a circuit must be equal to zero. KVL states that the sum of all voltages in a closed loop in a circuit must be equal to zero.

3. How do I apply Kirchhoff's law to find the current I3 through the Amp meter?

To find the current I3 through the Amp meter, you will need to use KCL and KVL to set up a system of equations. First, apply KCL at the node where the current I3 flows. Then, apply KVL to the loop that includes the voltage source, resistor, and Amp meter. Solve the equations simultaneously to find the value of I3.

4. What is the significance of Kirchhoff's law in circuit analysis?

Kirchhoff's law is significant in circuit analysis because it allows us to determine the current and voltage in any point of a circuit, regardless of its complexity. These laws are essential in designing and troubleshooting electrical circuits.

5. Are there any limitations to Kirchhoff's law?

While Kirchhoff's law is a powerful tool in circuit analysis, it does have some limitations. These laws assume ideal conditions, such as no resistance in wires and perfect voltage sources. In real-world circuits, there may be some deviations from these ideal conditions, which can affect the accuracy of the calculations.

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