Help with this confusing circuit Using superposition find voltages

In summary: All current will flow trough the resistor at the top of the circuit. As for the bottom part, all the current will flow trough the resistance-free cable.
  • #1
nchin
172
0
Help with this confusing circuit! Using superposition find voltages!

The problem is

"In the following circuit, find the voltages at A,B, and C. Use or confirm with superposition."

I was able to find the current through the top one ohm resistors as .333A (sorry didnt label on my picture). but what do i do next?


PICTURE:
http://imageshack.us/a/img689/7025/circuit3a.jpg
 
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  • #2
You could try to analyze the lower part, and ignore the upper part for a while (as you know its contribution already). What is the current flowing through the resistor below B?
 
  • #3
There is a little trick here. Actually the circuit is quite simple (in fact, as simple as a circuit can be).

Hint: If you have two paths in a circuit and one of them has o resistance, all charges will flow trough that path.
 
  • #4
Vvs

It is very simple. Try using KCL and KVL.

For example:

I is flowing through the top resistor and 1A is flowing in the bottom left branch. Applying KCL at node A. I+1A will flow through the 1ohm resistor from Node A to Node B. Multiply that current by the 1 Ohm Resistor will give you the voltage drop across the 1ohm resistor so B=A-(I+1A)*1.

Continue analysis in a similar fashion for the rest of the circuit.

hope this helps
 
  • #5
VVS said:
It is very simple. Try using KCL and KVL.

For example:

I is flowing through the top resistor and 1A is flowing in the bottom left branch. Applying KCL at node A. I+1A will flow through the 1ohm resistor from Node A to Node B. Multiply that current by the 1 Ohm Resistor will give you the voltage drop across the 1ohm resistor so B=A-(I+1A)*1.

Continue analysis in a similar fashion for the rest of the circuit.

hope this helps

What you say is usually ok, but not for this paticular problem. All the current will flow only trough the resistor at the top of the circuit. As for the bottom part, all the current will flow trough the resistance-free cable.
 
  • #6
CFede said:
There is a little trick here. Actually the circuit is quite simple (in fact, as simple as a circuit can be).

Hint: If you have two paths in a circuit and one of them has o resistance, all charges will flow trough that path.

sorry I do not understand. Which two paths and which has 0 resistance?
 
  • #7
CFede said:
What you say is usually ok, but not for this paticular problem. All the current will flow only trough the resistor at the top of the circuit. As for the bottom part, all the current will flow trough the resistance-free cable.
Did you check the direction of the 1A source to the left?
There will be a current flow in the interior of the circuit.
 

FAQ: Help with this confusing circuit Using superposition find voltages

What is superposition and how does it apply to circuit analysis?

Superposition is a principle that states that the total response of a linear system is equal to the sum of the individual responses of each input. In circuit analysis, this means that we can break down a complex circuit into smaller, simpler circuits and analyze them separately before combining the results to determine the overall response.

How do I use superposition to find voltages in a circuit?

To use superposition, we first need to turn off all but one voltage or current source in the circuit. Then, we can analyze the circuit using traditional methods to find the voltage at the desired point. We repeat this process for each source in the circuit, keeping all other sources turned off. Finally, we add the individual voltage values together to get the total voltage at the desired point.

Can superposition be used for both DC and AC circuits?

Yes, superposition can be used for both DC and AC circuits as long as the circuit is linear. This means that the circuit components, such as resistors and capacitors, follow Ohm's law and other linear relationships.

Are there any limitations to using superposition in circuit analysis?

Superposition is a powerful tool for circuit analysis, but it does have some limitations. It can only be used for linear circuits, and it cannot be applied to nonlinear components such as diodes and transistors. Additionally, superposition assumes that the circuit is in a steady-state condition.

How can I check my results when using superposition to solve a circuit?

To check your results when using superposition, you can compare the total voltage calculated using superposition with the voltage calculated using traditional methods for the entire circuit. If the values match, then you can be confident in your solution. It can also be helpful to use simulation software or a breadboard to physically test the circuit and compare the results to your calculations.

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