| Phasors Interview Questions |
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I feel that I understand the Laplace and inverse Laplace transforms. When s is replaced with j omega I don't understand what I've done exactly. I see that the result is similar to what I was get if I started with phasors but that's about all I see.
Is s is replaced with sigma + j omega I feel clueless. Can anyone with an intuitive sense help me understand it better? I'm looking for different perspectives in hopes of coming across one that "clicks" so the more "off the beaten path" your perspective is, the more helpful it may be. Of course, a simple rehash of the theory may be the key as well.
In other words, anything will be appreciated. Thanks.
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...node voltages, V_1 and V_2. The angles must be expressed in the range -180 degrees <= theta <= 180 degrees.
Please see the circuit here:
http://dave.uta.edu/dillon/boggle/images...
i_s(t)=5cos(1000t)
v_s(t)=100cos(1000t-(45 degrees))
R_a=50 ohm
R_b=10 ohm
L=25 mH
C=10 microF
Since 1000t=wt (w being omega) when dealing with phasors, I calculated the impedance of L and C using 1000 as w. I got:
Z_L=j25
Z_C=-j100.
I figured time could be zero since I am calculating this circuit at an instant so I got:
i_s=5
v_s=50sqrt(2).
I used node voltage method to calculate the voltage across R_a, R_b, L, and C using the impedance that I found. For the equations I got:
V_1: -i_s+I_L+I_a=0
V_2: -I_a+I_C+I_b=0
For the voltages I got:
V_a=250angle0
V_b=v_s=50sqrt(2)
V_C=(207.107angle-90)
V_L=0angle0
My question is, how do I find V_1 and V_2? The sum of the voltages at the node should be zero which isn't right. Is it the sum of some the voltages? If so, which ones?
Thanks in advance!
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I believe I read that I can use either the real OR the imaginary axis when working with phasors (in other words, project the values onto either axis, obviously not both at the same time). Is there anything that determines which axis I can use?
The text I remember reading when I picked up this concept was using V and I instead of Real and Imaginary axises. This only helped to confuse me more...
Thanks.
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How would you write the signal for sin50pt as the real parts of rotating phasors. Also how would you write it as one-half the sum of a rotating phasors and its complex conjugate.
I'm not understanding what they are looking for. A little help.
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Hi,
im having trouble with ohms law (V = iR) and how it relates to phasors...
simply, does V=iZ or V=iY
Z being equivalent impedance of a circuit and
Y being equivalent admittance of a circuit...
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Is complex power a phasor? I don't think it is, but since it is a multiple of two phasors I'm not sure.
Also why is it beneficial to have a larger power factor? Is is so your average power is higher? Why wouldn't you want more reactive power? What exactly is reactive power's significance?
Thanks
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I'm always looking for a better way to visualize this s = sigma + jw, and exactly what s=jw (no sigma, the phasor case) is...
If there is a certain math topic to read please tell me, I will buy a math book and learn more math if that's what it takes.
If there is a way to demonstrate and see this in MATLAB please point me toward a tutorial or give me an idea of what to do to see it and I will do that...
Thanks
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I was given this example but I dont understand how to get the answers, the answers are given below each question.
Thanks in advance, any help is really appreciated!
Please follow the link to the question as I couldn't write it all in here so I uploaded it as an image file.
http://img76.imageshack.us/img76/773/shm...
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When I'm working a problem with Laplace and then instead of finding the inverse Laplace transform I replace s with jw, I feel like I'm just switching back to the phasors that I learned years before Laplace...
Is this the case?
Is this just a shortcut? Use Laplace to solve the circuit and then use phasors to get the steady-state result since both are easiest to use for those tasks?
Kind of like multiplying with polar and adding with rectangular?
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assume that a certain quantity I(t) changes over time as I(t)=I_0*cos(omega*t). A phasor is a vector whose length represents the amplitude I_0
http://i20.photobucket.com/albums/b241/t...
This vector is assumed to rotate counterclockwise with angular frequency omega; that way, the horizontal component of the vector represents the actual value I(t) at any given moment.
In parts 1 - 3 consider the four phasors shown in the diagram
http://i20.photobucket.com/albums/b241/t...
Assume that all four phasors have the same angular frequency omega.
______________________________________
1)
At the moment t depicted in the diagram, which of the following statements is true?
A) I_2 leads I_1 by pi.
B) I_1 leads I_2 by pi.
C) I_2 leads I_1 by pi/2.
D) I_1 leads I_2 by pi/2
______________________________________...
2)
At the moment shown in the diagram, which of the following statements is true?
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has any body got any advice or tips to help me get up to speed on phasors?any help would be appreciated.my tutor from last year wasn`t a big help.
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why not just apply kirchoff's law and add up the potentials across each passive circuit element. why do we need to calculate impedance to find out total potential across the circuit
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I have a series circuit of 3 components and a power supply, the supply voltage is stated as 12 sin wt ( i think this is 12v no angle (i.e 12 +j0)
across one of the components the voltage is stated as;
12sin(wt + 0.733) and another component is
12sin(wt - 0.96)
What is the voltage over the remaining component?
I've come up with a couple of solutions but just don't seem right. Any help would be appreciated.
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Maybe I'm forgetting something...
R and C in series, phasor impedance...
sqrt ( R^2 + 1/wC^2 )
with s-domain isn't it simply
R + 1/sC = R + 1/jwC ? no sqrt or squaring required?
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