Find the Equivalent Resistance in Complicated Electrical Circuits

In summary, the individual resistors in a complicated circuit can be identified as being connected in series or parallel by labeling them and the connection nodes. Redrawing the network can also help to clarify the relationships between the components. A step-by-step approach can be used to simplify the circuit and find the equivalent resistance. It is important to properly label the components in order to avoid confusion.
  • #1
Grievery
3
0
Hi! I have been trying to understand how a "complicated" circiut can be transformed to show which resistors are connected in series and which are parallel... Sometimes I manage to do it but it's often too hard for me because I can't find any sort of algorithm about it. Could anybody show me "step-by-step" how to transform this circuit for example...?
arx1303670379t.jpg

We need to find the equivalent resistance...
Thank you in advance!
 
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  • #2
It's always a good idea to label the components in a diagram. In this case your resistors should be numbered R1, R2 etc. This allows people to identify what is being referred to and, if the OP doesit, doesn't waste 2 posts.
Alternatively you can label the connection nodes, A, B, C etc (which you have already started, but not finished).

I will comment (ask) if your diagram is correct since R1 and R2 are (almost) shorted out.

Can you see which resistors I mean by R1 and R2?

Oh and welcome to PF
 
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  • #3
First of all, thank you for the very quick response... I have labeled the resistors... Now, how can I find the equivalent one.
P.S. The answer is 3 ohms.
jdv1303671601e.jpg
 
  • #4
I find it often helpful to redraw the network to bring out the relationships. Sometimes you have to do this several times to get a clear result.

The attachment shows a sequence of single step series or parallel simplifications leading to the desired result.

Although I agree with the 3 ohm answer I have left you do do some of the work in the intermediate steps.

Hope this helps
 

Attachments

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  • #5
Well.. thank you once again! :) I hope now I can figure out HOW to do it myself...
 

What is the purpose of finding the equivalent resistance in complicated electrical circuits?

The equivalent resistance in a complicated electrical circuit is the single value that represents the combined resistance of all the individual components in the circuit. It is important to find the equivalent resistance because it allows us to simplify the circuit and make calculations and predictions about the flow of current and voltage.

How do you calculate the equivalent resistance in a complicated electrical circuit?

To calculate the equivalent resistance, you can use Ohm's Law, which states that resistance is equal to voltage divided by current. However, in a complicated circuit, you may need to use a combination of series and parallel resistors, which requires a different formula. You can also use a tool called a circuit solver to help you find the equivalent resistance.

What is the difference between series and parallel resistors?

In a series circuit, the resistors are connected end-to-end, so the current flows through each resistor one after the other. The total resistance in a series circuit is equal to the sum of all the individual resistances. In a parallel circuit, the resistors are connected side by side, so the current is divided among them. The total resistance in a parallel circuit is less than the smallest individual resistance.

Can you have a negative equivalent resistance?

No, it is not possible to have a negative equivalent resistance. Resistance is a physical property of a material and cannot have a negative value. If your calculations result in a negative equivalent resistance, it is likely due to an error in your calculations or a faulty component in the circuit.

How can finding the equivalent resistance help in circuit analysis?

By finding the equivalent resistance, you can simplify a complicated circuit into a single resistor, making it easier to analyze and understand. It also allows you to make predictions about the behavior of the circuit and determine the amount of current and voltage at different points in the circuit. This information is essential for troubleshooting and designing new circuits.

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