Engineering Applying Thevenin's theorem to AC circuits

AI Thread Summary
The discussion revolves around the application of Thevenin's theorem to AC circuits, with a focus on the phase angle and imaginary components of loads. A participant expresses confusion over the sign of the imaginary part of a 50 Ω load, questioning whether a lagging power factor results in a negative phase angle. Others clarify that this understanding is incorrect, emphasizing that a lagging power factor corresponds to a positive imaginary component. The conversation highlights the importance of correctly interpreting phase angles in AC circuit analysis. Overall, the thread serves as a resource for clarifying misconceptions about power factors and their implications in circuit calculations.
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Homework Statement
FIGURE 1 shows a 50 Ω load being fed from two voltage sources via
their associated reactances. Determine the current i flowing in the load by:

(a) applying Thévenin’s theorem
(b) applying the superposition theorem
Relevant Equations
Thevenin equivalents, polar & rectangular conversions
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Image (2).jpg

So I've seen other threads on here with the same problem from a few years ago, and I'm just not getting the same answers. However, I followed along with a similar problem in the textbook and used all the same methods, so can't understand where I've gone wrong, or if I even am wrong. Also not sure if its ok that the current should be at an angle greater than 90 degrees
 
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The Electrician said:
See the first few posts in this thread: https://www.physicsforums.com/threads/thevenins-theorem.775385/

You have the sign of the imaginary part of the 50 Ω load wrong.
I thought a lagging power factor leads to a negative phase angle, and thus a negative imaginary component. Is that not right?
 
The Electrician said:
That is not right.
Look here: https://en.wikipedia.org/wiki/Power_factor#Lagging_and_leading_power_factors

Part way down the page under the heading "Lagging and leading power factors" you'll find discussion of the topic.
I don't know why I was so set on it being negative. I think I must have mixed it up with the angle between current and voltage maybe. Thanks for your help
 

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