Engineering Finding the frequency of a series parallel circuit using complex notation

AI Thread Summary
The discussion focuses on determining the frequency, ω, of a series-parallel circuit using complex notation, specifically when the current ig is in phase with the voltage vg. Participants emphasize the importance of calculating the impedance of the circuit components and expressing it in the form of a + jb, where the imaginary part must equal zero at resonance. Users express difficulty in simplifying the equations and finding accurate values for ω. Guidance is provided to separate the impedance into real and imaginary parts to facilitate the calculation. The conversation highlights the need for clear attempts at solving the problem to receive effective assistance.
Karma1
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The frequency, ω, of the source in the circuit of Figure 2 is adjusted until ig is in phase with vg.

(a)using complex notation, determine the value of ω (rad/sec)

Can anyone out there please help with this question? I've tried multiple methods but I am really struggling with simplifying the equation and my answers are wildly inaccurate.

(Please see attached document for details of the circuit)
 

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Karma1 said:
The frequency, ω, of the source in the circuit of Figure 2 is adjusted until ig is in phase with vg.

(a)using complex notation, determine the value of ω (rad/sec)

Can anyone out there please help with this question? I've tried multiple methods but I am really struggling with simplifying the equation and my answers are wildly inaccurate.

(Please see attached document for details of the circuit)

You'll have to demonstrate an attempt so that we can see how to help.
 
Karma1 said:
Ive tried multiple methods but I am really struggling with simplifying the equation and my answers are wildly inaccurate.
Hi Karma1! http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

To get you started, at a frequency ω, what is the impedance of 1kΩ || 500mH? Express your answer in the form: a + jb
 
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Hey NascentOxygen,

I havn't got a clue where to start I'm sorry.
 
This is what I've managed so far.
 

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    Complex Calculations.jpg
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j is not zero; j is the square root of -1. What is zero at resonance is the imaginary term of the impedance.

You've got the correct approach for determining the impedance. What you need to do is separate it into its real and imaginary parts; write it in the form: [real part] + j[imaginary part], and then deal with finding a value for ω that makes [imaginary part] zero.
 

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