Equivalent resistance of tricky circuits?

In summary, the conversation is about finding the equivalent resistance between points A and B in a circuit with a middle point B. The student has already calculated the equivalent resistance between A and C, but is struggling to find the equivalent resistance at point B. The suggestion is to treat the circuit as a cube of resistors and use Kirchoff's Law to find the equivalent points at equal potential and connect them with a wire. An advanced approach is to also consider the points D, E, G and J, H, C as equivalent and connect them with a wire.
  • #1
asifrulzz
4
0
equivalent resistance of tricky circuits?

Homework Statement


what is the equivalent resistance between A and B?
img002.jpg



Homework Equations


kirchoffs law for voltage and current


The Attempt at a Solution


i got the equivalent resistance between A to C as 3R/4
but i have to find the resistance between A to B but point B is in the middle of the circuit and i don't know how to approach it
i am stuck on this
please help!
 
Last edited:
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  • #2
asifrulzz said:

Homework Statement


what is the equivalent resistance between A and B?https://www.physicsforums.com/attachments/43813


Homework Equations


Kirchhoff's Law for voltage and current


The Attempt at a Solution


i got the equivalent resistance between A to C as 3R/4
but i have to find the resistance between A to B but point B is in the middle of the circuit and i don't know how to approach it
i am stuck on this
please help!
Hello asifrulzz. Welcome to PF !

No attachment found !
 
  • #3


i have attached the circuit diagram
 
  • #4


What approach have you tried? Can you show your work so far?
 
  • #5


i have always calculated equivalent resistance at the ends
i don't have any idea how i would reach at point B which is in the middle
 
  • #6


help please!
anybody
thanks in advance
 
  • #7


The network of resistors is equivalent with a cube of resistors. You can use that the equivalent points are at equal potential if you connect a voltage source between points A and B, and can be connected with a wire.

ehild
 

Attachments

  • cubes.JPG
    cubes.JPG
    17.1 KB · Views: 2,003
Last edited:
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Likes Rafij Sadiq
  • #8


A step ahead: The points D,E,G of the cube are equivalent and can be connected with a wire. The same holds for J, H, C.

ehild
 

Attachments

  • cuberes.JPG
    cuberes.JPG
    11 KB · Views: 1,601

1. What is meant by equivalent resistance?

Equivalent resistance refers to the single resistance value that can replace a complex circuit and produce the same current flow as the original circuit. This simplifies circuit analysis and makes it easier to determine the overall behavior of the circuit.

2. How do I calculate the equivalent resistance of a tricky circuit?

The equivalent resistance of a tricky circuit can be calculated using the formula Req = R1 + R2 + R3 + ..., where R1, R2, R3, etc. represent the individual resistances in the circuit. This formula applies to both series and parallel circuits, but may differ for more complex circuits.

3. Is it possible for the equivalent resistance to be lower than the lowest individual resistance in a circuit?

Yes, it is possible for the equivalent resistance to be lower than the lowest individual resistance in a circuit. This can occur in parallel circuits, where the combined resistance of multiple paths is lower than the resistance of any single path.

4. Can the equivalent resistance of a circuit be negative?

No, the equivalent resistance of a circuit cannot be negative. Resistance is a physical property that represents the opposition to current flow, and it cannot have a negative value. If the calculated equivalent resistance is negative, it is likely an error in the calculation.

5. How does the arrangement of resistors in a circuit affect the equivalent resistance?

The arrangement of resistors in a circuit can significantly affect the equivalent resistance. In series circuits, the equivalent resistance is the sum of all individual resistances, while in parallel circuits, it is less than the smallest individual resistance. Additionally, the equivalent resistance may also change if resistors are added or removed from the circuit.

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