Current of Phasor going in CCW direction

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Discussion Overview

The discussion revolves around the interpretation of phasor representation in relation to current direction, specifically addressing whether a counterclockwise (ccw) direction affects the sign and phase of the current expression. The scope includes mathematical reasoning and conceptual clarification regarding phase shifts and amplitude inversion.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant questions whether the current being in the ccw direction necessitates a negative sign in the expression for current, suggesting it could be -5cos(10t - 45) instead of 5cos(10t - 45).
  • Another participant notes that inverting the amplitude is equivalent to adding a 180-degree phase shift, implying that the direction of rotation may require a different adjustment in the equation.
  • A further contribution suggests that a 180-degree phase shift would modify the angle to 5cos(10t + 135), although this interpretation is challenged by another participant.
  • There is a call for clarification on where to apply the negative sign in the equation to achieve the desired rotation direction.

Areas of Agreement / Disagreement

Participants express differing views on how to correctly represent the current in relation to its direction of rotation, indicating that the discussion remains unresolved with multiple competing interpretations.

Contextual Notes

Participants have not fully resolved the implications of phase shifts versus amplitude inversion, and there is uncertainty regarding the correct placement of negative signs in the equations.

smstepanic
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Hi,

I feel I have solved this problem correctly (solving for vo(t)), however since the current is going in the ccw direction, would this make the current -5cos(10t - 45) versus 5 cos(10t -45)? This may be a simple question, so I am just making sure. Thanks!
 

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smstepanic said:
Hi,

I feel I have solved this problem correctly (solving for vo(t)), however since the current is going in the ccw direction, would this make the current -5cos(10t - 45) versus 5 cos(10t -45)? This may be a simple question, so I am just making sure. Thanks!
Inverting the amplitude is the same as adding a 180-degree phase shift. To make the rotation direction different, you need a negative sign in a different place...
 
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berkeman said:
Inverting the amplitude is the same as adding a 180-degree phase shift. To make the rotation direction different, you need a negative sign in a different place...

I think I understand. A 180 degree phase shift would apply to the -45 degrees. So 5cos(10t + 135)?
 
smstepanic said:
I think I understand. A 180 degree phase shift would apply to the -45 degrees. So 5cos(10t + 135)?
Um, no, that's not what I meant.

Regardless of the problem you posted, if you want the phasor to rotate in the opposite direction, you need to multiply by -1 where in the equation? Think about how each term in the equation affects the function...
 
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