Calculate Current in Homework Statement | KCL

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In summary: Yeah, this has to be the answer.In summary, the current I will be present through the wire, even if there is zero potential difference. You can make use of superposition principle to calculate this current.
  • #1
john88
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Homework Statement





Homework Equations



KCL


The Attempt at a Solution



I have some question for this circuit.

http://img510.imageshack.us/my.php?image=questpt3.jpg

I want to calculate the current I, my first thought was that it can't go any current because the potential difference is zero. But then I thought that the current source can produce a current even if there is zero potential, so there is a current I anyway. I am correct?

I would appreciate some help.
 
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  • #2
There will be a current through the wire. The potential difference across any ideal wire is 0, but still there will be current flow if the other circuit element are present. You can make use of superposition principle to do this problem.
 
  • #3
ok so if I use the superposition method I get this:

First I have this situation

http://img387.imageshack.us/my.php?image=firstum9.jpg

First I replace the current source whit an open circuit and I end up whit this:

http://img66.imageshack.us/my.php?image=second2ud4.jpg

So I = -(2.71/R9)


Next I replace the voltage source whit a short-circuit

http://img399.imageshack.us/my.php?image=second1br1.jpg

(im not sure if that step is right, I replaced the voltage source whit a short-circuit. So the resitance R10 got short circuted and I took it away correct?)

Then I = I1 (current source) not sure of that either...

which means that the total current I is equal to I1 -(2.71/R9)
 
  • #4
john88 said:
You could have just reverse the direction of the battery instead of writing a negative voltage source, you know.

john88 said:
First I replace the current source whit an open circuit and I end up whit this:

http://img66.imageshack.us/my.php?image=second2ud4.jpg

So I = -(2.71/R9)
What happened to the 2k resistor?

Next I replace the voltage source whit a short-circuit

http://img399.imageshack.us/my.php?image=second1br1.jpg

(im not sure if that step is right, I replaced the voltage source whit a short-circuit. So the resitance R10 got short circuted and I took it away correct?)
Yes, and so is the R9 resistor, so you have I = I1 here as well.
 
  • #5
Well ye I took away the 2k resistor, and that's not correct but I still end up whit the same answer when I use the current divider, but its not negative. I = 2.72/6500

So now I_tot = I + I1

This must be the right answer
 

1. What is KCL and how does it relate to calculating current?

KCL stands for Kirchhoff's Current Law, which is a fundamental law in electrical engineering that states that the sum of currents entering a node (or junction) in a circuit must equal the sum of currents leaving the node. This law is used to calculate the current flowing through different branches of a circuit.

2. How do I apply KCL in a circuit to calculate current?

To apply KCL, you need to identify all the nodes in the circuit and label them with a unique name or number. Then, at each node, write an equation that equates the sum of all the currents entering the node to the sum of all the currents leaving the node. Finally, solve the equations simultaneously to find the current values.

3. Can KCL be used in all types of circuits?

Yes, KCL can be used in any type of circuit, whether it is a simple series circuit or a complex parallel circuit. It is a fundamental law that applies to all types of circuits and is used extensively in circuit analysis and design.

4. How does KCL help in troubleshooting circuit problems?

KCL is a powerful tool for troubleshooting circuit problems. By applying KCL at different nodes in a circuit, you can identify where the current is not flowing as expected. This can help you pinpoint faulty components or connections and fix them to restore the proper functioning of the circuit.

5. Are there any limitations to using KCL in circuit analysis?

While KCL is a useful and accurate tool for calculating current in circuits, it does have some limitations. For example, it assumes that the current flows in a single direction in a circuit, and it does not take into account the time-varying nature of some electrical components. Additionally, KCL can become more complex to apply in circuits with multiple loops or when the number of nodes is large.

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