How Do You Calculate Power for Components C and E in a Circuit?

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Discussion Overview

The discussion revolves around calculating power for components C and E in a circuit, specifically focusing on the role of the current ix and the voltage across the components. The scope includes technical reasoning and circuit analysis.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant expresses uncertainty about how to handle the current ix in the context of calculating power for components C and E.
  • Another participant states that the current ix is given as 3A but in the opposite direction, leading to ix = -3A, and calculates the voltage across component E as V(E) = 2 * ix = -6V.
  • This calculation is challenged by the same participant who notes that for the conservation of energy to hold, E must be 6V, suggesting to use E = 6V for calculations instead.
  • A different participant suggests that ix could be ignored, arguing that the current and voltage across each element are known, allowing the use of P = V.I for power calculations.
  • This participant also mentions specific voltages across components, indicating 10 volts for one element and 4 volts for another, leading to a 6-volt difference across a component referred to as a "rhombus." They note uncertainty about whether to assign a positive or negative sign to power calculations to indicate power sources or sinks.

Areas of Agreement / Disagreement

Participants do not reach a consensus on how to handle the current ix or the implications for calculating power. Multiple competing views remain regarding the treatment of voltages and the necessity of ix in the calculations.

Contextual Notes

There are limitations regarding the clarity of the voltage across certain components and the assumptions made about the direction of current and voltage polarities. The discussion reflects uncertainty about the correct approach to power calculations in this circuit context.

jojobananas
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My biggest issue is I don't know what to do with the ix
So I really just need to know how to calculate power for C and E. Thank you!
 
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The ix current is given as 3A, but it is in the opposite direction, so we say ix = -3A.

E is a Current Controlled Voltage Source (CCVS) which has the voltage across it depending on the current ix. We know ix = -3A so V(E) = 2 * ix = -6V.

This doesn't make sense for the circuit though, as we need E = 6V for the law of conservation of energy not to be violated, so pretend E = 6V for your calculation.
 
Last edited:
thank you!
 
jojobananas said:
My biggest issue is I don't know what to do with the ix

Actually, I think you could ignore it! * :rolleyes:

Simply because you know the current through each of the elements, and you know the magnitude of the voltage across each, so for each P=V.I

Okay, you may not have been told the voltage across that rhombus-thing :smile:
but the element in the centre has 10volts, and that on the right has 4volts, leaving (paying close attention to polarities) 6volts across the rhombus. (I must admit I didn't recognize it as a CCVS until Zryn pointed that out.)

It's not clear whether you need to attach a + or - sign to each power calculation, to indicate whether a power source or sink. If in doubt, it won't hurt to do so.

*you can do this in this case because there seems to have been more information provided on I's and V's than absolutely necessary
 

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