Trying to apply superposition method to circuit, not working

In summary, the conversation discusses the use of superposition to calculate the power dissipated in a double loop circuit with two batteries and a 6 Ω resistor. The method involves replacing one battery with a short and solving for the voltage and current through the resistor, then doing the same with the other battery and adding the individual values. However, it is pointed out that power cannot be added by superposition and instead current or voltage should be computed and then used in the power equation.
  • #1
TheKShaugh
22
0

Homework Statement



A double loop circuit is shown in the figure below.[/B]
FVTMCtE.png

The Emf
mimetex.gif
x = 6.00 V and the Emf
mimetex.gif
w = 19.00 V. Both are shown on the diagram. Calculate the power dissipated in the 6 Ω resistor located on the extreme right in the circuit.

Homework Equations



V=IR, P=VI

The Attempt at a Solution



I tried using superposition, where I replaced one battery with a short and solved for the voltage and current through the 6 ohm resistor, and the did the same by replacing the other battery with a short. The total current and voltage is the sum of the individual values. I plugged those final values into P=VI and got the wrong answer. Should this method work and I just did the work wrong or is there something I'm not aware of?
 
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  • #2
Sounds like you did it right but without your posting your work it's impossible for us to see where you might have gone wrong.
 
  • #3
TheKShaugh said:
I tried using superposition, where I replaced one battery with a short and solved for the voltage and current through the 6 ohm resistor, and then did the same by replacing the other battery with a short. The total current and voltage is the sum of the individual values. I plugged those final values into P=VI and got the wrong answer. Should this method work and I just did the work wrong or is there something I'm not aware of?
You cannot add power by superposition. You can compute current I by superposition:
I = I1 + I2.
Then P = I^2 R.
Or you could have computed V1 and V2 by superposition, then P = VI = (V1 + V2)(V1 + V2)/R.
 
  • #4
rude man said:
You cannot add power by superposition. You can compute current I by superposition:
I = I1 + I2.
Then P = I^2 R.
Or you could have computed V1 and V2 by superposition, then P = VI = (V1 + V2)(V1 + V2)/R.
DOH ! I assumed that's what he was doing but on rereading I see I just glossed over what he really said. Good catch.
 

1. Why is the superposition method not working on my circuit?

The superposition method may not work on a circuit for a few reasons. One possibility is that the circuit contains dependent sources, which cannot be easily separated for the superposition method. Another reason could be that the circuit has non-linear elements, which cannot be analyzed using the superposition method. Additionally, the circuit may have been set up incorrectly, leading to incorrect results.

2. How do I know if my circuit is suitable for the superposition method?

To determine if the superposition method is applicable to your circuit, you must first check for dependent sources and non-linear elements. If these are present, the superposition method cannot be used. Additionally, the circuit must have multiple sources that can be turned off individually, and the circuit must be in a steady-state condition.

3. What are the limitations of the superposition method?

The superposition method is limited to circuits with linear, time-invariant components. This means that the components must have a constant relationship between voltage and current and their behavior cannot change over time. Additionally, the method cannot be used for circuits with dependent sources or non-linear elements.

4. How can I troubleshoot my circuit if the superposition method is not working?

If the superposition method is not working on your circuit, you can try analyzing the circuit using other methods such as nodal analysis or mesh analysis. Additionally, double-check your circuit setup and make sure all sources are set up correctly. It may also be helpful to redraw the circuit and simplify it to make it easier to analyze.

5. Can the superposition method be used for both AC and DC circuits?

Yes, the superposition method can be used for both AC and DC circuits as long as the circuit satisfies the requirements of the method. However, for AC circuits, the sources must be sinusoidal and in the same frequency. The superposition method can be applied separately for each frequency component to obtain the overall solution.

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