Find the Electric power of the Current source

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Discussion Overview

The discussion revolves around calculating the electric power of a current source within an electrical network, utilizing loop equations and analyzing the current and voltage across various resistors. Participants explore different approaches to find the power output of the current source.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant reports finding the electric power of a voltage source to be 11.4 W and seeks assistance in calculating the power of the current source.
  • Another participant asks for the current in resistor R4 and the corresponding voltage across it.
  • A participant states the current in R4 is 0.2 A and calculates the voltage across R4 to be 1.6 V, questioning the correctness of this calculation.
  • Another participant suggests that knowing the voltage across R4 could assist in determining the power produced by the current source.
  • A participant expresses a need for clarification on how to find the current source's power, stating a desired final answer of 36.9 W.
  • One participant indicates that the voltage across the current source can be found by applying Kirchhoff's Voltage Law (KVL) around a specific path that includes resistors RL and R3.
  • A participant calculates the voltage across the current source as 18 V when including R4, but finds a different voltage of 16.4 V when excluding R4, leading to a power calculation of 36.9 W.
  • Another participant explains that R4 is in parallel with the current source and that the path for KVL should not include R4 to avoid closing the loop incorrectly.

Areas of Agreement / Disagreement

Participants express differing views on the inclusion of R4 in the calculations for the current source's power, indicating a lack of consensus on the correct approach to take.

Contextual Notes

Participants have not fully resolved the implications of including or excluding R4 in their calculations, and there are unresolved assumptions regarding the circuit configuration and the application of KVL.

omni
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in the picture you can see the electrical network.
in blue is the Current of each side of the electrical network. (did it with loop equations)
i asked to find the Electric power of E and the Electric power of the Current source.

so for E i found it and i got pe=11.4w.

i also know what is the Current in each resistor.

i have no problem to find the electric power of voltage source, but for current source i need some help.

thanks.
 

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omni said:
i also know what is the Current in each resistor.
That's good. What is the current in R4? And therefore, what is the voltage across R4?
 
the current in R4 is 0.2A and the voltage across R4 is 0.2*8=1.6v

do i correct ?

thanks.
 
omni said:
the current in R4 is 0.2A and the voltage across R4 is 0.2*8=1.6v

do i correct ?

thanks.
I don't know if it's correct (unless you want to show all your work so far), but knowing the voltage across R4 should help you with finding the power produced by the current source.
 
ok so just tell me how is help me to find the current source?

the final answer need to be P( of the current source)=36.9w.

thanks
 
You need to find the voltage that appears across the current source. A path can be drawn from one terminal of the current source through RL and R3 and back to the current source. Use KVL around that path.
 
the voltage that appears across the current source, i get 18v (if i include R4)

but if i take only RL and R3 i get 16.4v and then multiply it by 2.25A i get that the Plo=36.9w and for real this is the correct answer.

can you explain me why i not need to include R4?

thank you.
 
omni said:
the voltage that appears across the current source, i get 18v (if i include R4)

but if i take only RL and R3 i get 16.4v and then multiply it by 2.25A i get that the Plo=36.9w and for real this is the correct answer.

can you explain me why i not need to include R4?

thank you.

R4 is connected to the same nodes as the current source (they're in parallel). The path that you want should have ends that start at one node (B) and end at the other (A), and not 'close the gap'.

attachment.php?attachmentid=41354&stc=1&d=1322587471.jpg
 

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great answer thank you :)
 

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