Complex Notation - Electrical Circuit

In summary, the conversation discusses finding expressions for the output voltage and input current using complex notation. There is confusion regarding the value of an inductor and incorrect assumptions about the circuit. A physics tutor may be consulted for further assistance.
  • #1
amy1983
7
0

Homework Statement



1 (a) using complex notation, find an expression for the output voltage, v0
1 (b) using complex notation, find an expression for the input current, ig, and hence determine the phase angle of ig relative to vg


Homework Equations





The Attempt at a Solution


See attached two attempts, in jpgs. I've gotten myself very confused! If someone could advise that would be great.
 

Attachments

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  • #2
1.2 mH is not the same as 0.001 H; you've dropped a significant figure. This in turn has significantly altered your impedance value for the inductor, with the error propagating through your further calculations.

The input is specified as a voltage source, and you've treated it as a current. This is not correct.

You've then assumed that both the resistor and the inductor are conducting the entire "current" of 40A. They are in parallel so this is not possible; Parallel branches have the same potential difference, but not necessarily the same current. It's series components that have the same current.
 
  • #3
Thank you gneill, i'll have to look at it and perhaps get a physics tutor.
 

1. What is complex notation in electrical circuits?

Complex notation in electrical circuits is a mathematical representation of the voltages, currents, and impedances in an AC circuit. It uses complex numbers to represent the magnitude and phase angle of these quantities, allowing for more accurate analysis of circuit behavior.

2. Why is complex notation used in electrical circuits?

Complex notation is used in electrical circuits because it simplifies the analysis of AC circuits by combining the magnitude and phase information of voltages, currents, and impedances into a single mathematical expression. This allows for easier calculations and better understanding of circuit behavior.

3. How is complex notation related to phasors?

Complex notation is closely related to phasors, as both use complex numbers to represent the magnitude and phase of AC quantities. Phasors are a graphical representation of complex notation, with the magnitude represented by the length of the phasor and the phase angle represented by the angle it makes with the reference axis.

4. Can complex notation be used in DC circuits?

No, complex notation is only used in AC circuits. In DC circuits, all quantities are represented by real numbers, as there is no phase difference between voltages and currents. Therefore, complex notation is not necessary for analysis in DC circuits.

5. How do you convert complex notation to polar or rectangular form?

To convert complex notation to polar form, you can use the equation z = |z| * e^(j*θ), where |z| is the magnitude of the complex number and θ is the phase angle. To convert to rectangular form, you can use the equations Re(z) = |z| * cos(θ) and Im(z) = |z| * sin(θ), where Re(z) is the real part and Im(z) is the imaginary part of the complex number.

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