Have the Currents Been Labelled Correctly?

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In summary, the conversation discusses a circuit problem where the currents need to be found using Kichhoff's Laws and Ohm's Law. The person is struggling to get the correct answer and believes there may be errors in the book they are using. The equations and results are shown, and it is determined that the current i_{2} should be 11/6 A, not 13/6 A as stated in the book. The voltage drop across the 6 ohm resistor is fixed at 11V, making the 11/6 A result logical. The correctness of the labelling of currents is also questioned.
  • #1
Addem
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Homework Statement



Linked below is a rough picture of the circuit for which I need to find the currents.

https://docs.google.com/drawings/pub?id=1jY6r1yjOf9OG5VixjZKcQbG2rj-ZQ7LZzaybGzkjva0&w=960&h=720

Homework Equations



Kichhoff's Laws, Ohm's Law.

The Attempt at a Solution



I'm doing a self-study using a book that I think may be riddled with errata, so I keep finding that I'm getting a result which disagrees with the answer the back and cannot see why my answer differs. I get the system of equations

[itex]11 - 3i_{3} + 1 = 0[/itex]

[itex]11 + 6i_{2} = 0 [/itex]

[itex]-3i_{3} + 1 -6i_{2} = 0[/itex]

[itex] i_{3}=i_{1}+i_{2}[/itex]

I believe my choice of direction of flow is consistent and cannot affect my solution up to a change of sign. The book produces the result that [itex]i_{2}=13/6[/itex] when I obtain 11/6.
 
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  • #2
Addem said:

Homework Statement



Linked below is a rough picture of the circuit for which I need to find the currents.

https://docs.google.com/drawings/pub?id=1jY6r1yjOf9OG5VixjZKcQbG2rj-ZQ7LZzaybGzkjva0&w=960&h=720

Homework Equations



Kichhoff's Laws, Ohm's Law.

The Attempt at a Solution



I'm doing a self-study using a book that I think may be riddled with errata, so I keep finding that I'm getting a result which disagrees with the answer the back and cannot see why my answer differs. I get the system of equations

[itex]11 - 3i_{3} + 1 = 0[/itex]

[itex]11 + 6i_{2} = 0 [/itex]

[itex]-3i_{3} + 1 -6i_{2} = 0[/itex]

[itex] i_{3}=i_{1}+i_{2}[/itex]

I believe my choice of direction of flow is consistent and cannot affect my solution up to a change of sign. The book produces the result that [itex]i_{2}=13/6[/itex] when I obtain 11/6.
attachment.php?attachmentid=49266&stc=1&d=1342999707.png

Added in Edit:

If i2 = 11/6 A, then the voltage drop across the 6Ω resistor is 11 V, which makes perfect sense. So, it looks like you are correct !
 

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  • #3
I agree. The voltage across the 6 ohm resistor is fixed at 11V so the current is simply 11/6 amps.

Have they/you labelled the currents correctly?
 

FAQ: Have the Currents Been Labelled Correctly?

What are the basic components of a circuit?

The basic components of a circuit include a power source, such as a battery or generator, conductors (wires) to carry the current, and loads, such as resistors, capacitors, and inductors, which use the energy from the power source.

What is Ohm's Law and how is it used to solve circuits?

Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage applied and inversely proportional to the resistance of the conductor. This means that by knowing two of the values (voltage, current, or resistance), we can use the equation V=IR to solve for the third value.

How do you calculate the total resistance of a series circuit?

In a series circuit, the total resistance is equal to the sum of the individual resistances. This can be calculated by adding the resistances of each component, or by using the formula Rtotal = R1 + R2 + ... + Rn.

What is Kirchhoff's voltage law and how is it applied in circuit analysis?

Kirchhoff's voltage law states that the sum of all voltages in a closed loop must equal zero. This means that the total voltage drop across all components in a series circuit must equal the voltage of the power source. This law is used to calculate unknown voltages in a circuit.

How do you use the node voltage method to solve a circuit?

The node voltage method involves assigning unknown voltages to each node in a circuit, and then using Kirchhoff's current law to create equations to solve for those node voltages. This method is useful for solving circuits with multiple voltage sources and complex configurations.

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