# Question about Thévenin's theorem assignment

Discussion in 'Electronics Homework Help' started by nikola1912, May 20, 2018.

1. ### nikola1912

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May 20, 2018
In this task I'm supposed to determine the value of current between points A and B (Iab). In order to do that I have to calculate the voltage between those 2 points. And in order to do that I have to calculate the value of current passing from point A to point B. But current I1 gets split in one point. So through capacitor C4 is passing current I2 instead of I1.

What my question is, how do I calculate the value of current I2? And did I correctly calculate the value of I1? And also did I define voltage Uab right?

The whole task is supposed to be done in complex numbers btw. Sorry if I misspelled something. Also I put a picture from the book if you can't see the values.

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2. ### nikola1912

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May 20, 2018
This is what I meant to write in the first picture.

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3. ### Ratch

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Mar 10, 2013
I get the impression that you do not have any idea of how to perform loop or node analysis to find circuit voltages or currents. You must learn how to do that before you have any chance of solving that problem.

Ratch

4. ### nikola1912

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May 20, 2018
Yeah that really helps me out a lot. Thanks.

5. ### Ratch

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Mar 10, 2013
You cannot expect this forum to conduct a course in circuit analysis. We can answer specific questions about that subject, but the basic knowledge and background has to be acquired by you.

Ratch

hevans1944 likes this.
6. ### Laplace

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Apr 4, 2010
On first seeing this circuit, my first inclination was to perform a nodal analysis in the complex frequency domain, because that is how I always analyze circuits. But realizing that this particular problem is in the steady-state frequency domain, it can be redrawn as simple resistors & batteries, equations derived to solve for the node voltages, then substitute into these equations the corresponding complex-valued impedance and voltage sources in place of the resistors & batteries.

Here is the form of the original circuit redrawn as resistors & batteries. It may be less daunting to derive the equations in a simple resistor form rather than in complex impedance form (but use no numerical values until the final step.)

Here is the resistor circuit slightly rearranged. It should be easy enough to get a Thevenin equivalent for U1, R1, & R3. Then all that remains is a simple loop to analyze.