Calculating Effective resistance

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In summary, the equivalent resistance between points A and B will be 2Ω+2Ω=4Ω. The current will not enter the triangle as equal amt of current enter from opposite sides, meaning the effective resistance will be 2Ω+2Ω=4Ω.
  • #1
pratyushag
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Homework Statement



In the given circuit,the equivalent resistance between points A and B will be?

Homework Equations


The Attempt at a Solution


My solution

Effective resistance will be 2Ω+2Ω=4Ω as the current will not enter the triangle as equal amt of current enter from opposite sides(Im not sure about this part)
 

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  • #2
pratyushag said:

Homework Statement



In the given circuit,the equivalent resistance between points A and B will be?

Homework Equations



The Attempt at a Solution


My solution

Effective resistance will be 2Ω+2Ω=4Ω as the current will not enter the triangle as equal amt of current enter from opposite sides(Im not sure about this part)
Correct !
 
  • #3
But why doesnot current enter if opp sides have equal amt of current
 
  • #4
pratyushag said:
But why doesnot current enter if opp sides have equal amt of current

Not sure what do you mean by "opp sides". If you redraw the circuit (see attachment), the three resistors short and no current flows through them.
 

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  • #5
Why do the resistors short?
 
  • #6
There is no potential difference across those 3 resistors in the "loop".
 
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  • #7
pratyushag said:
But why doesnot current enter if opp sides have equal amt of current

there is current in the loop that arrive at the same node, but the current is negligible. meaning not worth mentioning.

if you take one part of the loop at the same node to connect after the resistor near B, thereby creating another node, current that enters that series of 3 x 2Ω will meet at another node, this created a potential difference, and usually with p.d. and resistance, you can work out the I.
 
  • #8
pratyushag said:
Why do the resistors short?

because there is a physical short circuit shown in your original circuit.

The drawing produced by Pranav-Arora is electrically the same as yours just a different physical shape. He's not added any wire or nodes just changed the physical shape of the existing node.
 

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Last edited:

1. What is effective resistance?

Effective resistance, also known as equivalent resistance, is the single resistance value that can replace a combination of resistors in a circuit and produce the same overall resistance.

2. How is effective resistance calculated for resistors in series?

For resistors in series, the effective resistance is calculated by simply adding up the individual resistance values. In other words, the effective resistance is equal to the sum of the resistors in the circuit.

3. What is the formula for calculating effective resistance in parallel?

The formula for calculating effective resistance in parallel is 1/Reff = 1/R1 + 1/R2 + 1/R3 + ..., where Reff is the effective resistance and R1, R2, R3, etc. are the individual resistance values in the circuit.

4. Can the effective resistance of a circuit ever be lower than the lowest individual resistance?

No, the effective resistance of a circuit can never be lower than the lowest individual resistance. This is because resistors in parallel offer multiple pathways for current to flow, reducing the overall resistance of the circuit.

5. How does temperature affect the effective resistance of a circuit?

As temperature increases, the resistance of a material also increases. This means that the effective resistance of a circuit will also increase with temperature. Conversely, as temperature decreases, the effective resistance will decrease as well.

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