Revisiting Phasors: Understanding the w in VL

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In summary, The speaker is struggling with understanding phasors and the conventions that come with it. They have been using Schaums outline of electric circuits to refresh their knowledge. They are confused about the w (omega, frequency) that appears in the formula for VL and ask for clarification. Another person responds with the first derivative of cos(ax) with respect to x and the speaker realizes their mistake and thanks the person.
  • #1
CoolDude420
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Homework Statement


Hi,

I'm revisiting phasors again. This is one of the topics I've always struggled with. Every time I do a new module, they change a lot of the convention. I've been using Schaums outline of electric circuits recently to get refreshed. I'm just confused on this one part:

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Homework Equations

The Attempt at a Solution



My question is with the w that appears in the forumla for VL. I understand that the current was differentiated to -sin and I understand that L is the inductance from the inductor voltage equation and that I is the amplitude from the current, but where is the w(omega, frequency) coming from at the front?
 
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  • #2
CoolDude420 said:
but where is the w(omega, frequency) coming from at the front?
Do you know what the first derivative is of ##\cos(ax)## with respect to ##x## with ##a## being a constant?
 
  • #3
blue_leaf77 said:
Do you know what the first derivative is of ##\cos(ax)## with respect to ##x## with ##a## being a constant?
-asin(ax). I see now. Quite stupid of me. Guess I just got confused when we're using actual AC signals and not x. Cheers
 

1. What is a phasor and how does it relate to electrical signals?

A phasor is a complex number that represents the magnitude and phase angle of an alternating current (AC) signal. It is used to simplify the analysis of AC circuits by converting the time-domain signals into their equivalent phasor representation in the frequency domain.

2. How is the frequency of a phasor signal represented?

The frequency of a phasor signal is represented by the "w" or omega symbol. This symbol is used to denote the angular frequency, which is equal to 2π times the frequency in hertz (Hz). It is measured in radians per second (rad/s).

3. Why is it important to understand the "w" in VL when working with phasors?

The "w" in VL represents the angular frequency of a phasor signal. It is a crucial factor in understanding the behavior and analysis of AC circuits. The frequency of a signal affects its impedance and phase, which in turn, impacts the overall performance of the circuit. Therefore, understanding the "w" in VL is essential for accurate analysis and design of AC circuits.

4. How does the "w" in VL change in different AC circuits?

The "w" in VL remains constant in a circuit with a purely resistive load. However, in circuits with inductive or capacitive elements, the "w" in VL can change due to the effects of reactance. Inductive elements cause a phase shift of +90 degrees and increase the value of "w" in VL, while capacitive elements cause a phase shift of -90 degrees and decrease the value of "w" in VL.

5. Can the "w" in VL be negative?

No, the "w" in VL cannot be negative because it represents the frequency of an AC signal. Frequencies cannot be negative values. However, the phase angle of a phasor can be negative, which indicates a phase shift in the opposite direction from the reference signal.

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