Equivalent resistance with a short circuit

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SUMMARY

The discussion centers on calculating the equivalent resistance in a circuit with a short circuit present. The key conclusion is that the subnetwork containing resistors R1, R2, and R3 is effectively bypassed due to the short circuit, which has a resistance of zero Ohms. Therefore, the only resistor that contributes to the equivalent resistance is R4. This understanding clarifies that any resistors in parallel with a short circuit do not affect the total resistance.

PREREQUISITES
  • Understanding of Ohm's Law
  • Familiarity with series and parallel resistor combinations
  • Knowledge of short circuit behavior in electrical circuits
  • Basic circuit analysis techniques
NEXT STEPS
  • Study the concept of short circuits and their impact on circuit analysis
  • Learn about calculating equivalent resistance in complex circuits
  • Explore series and parallel resistor configurations in detail
  • Review circuit simplification techniques using Thevenin's and Norton's theorems
USEFUL FOR

This discussion is beneficial for electrical engineering students, circuit designers, and anyone involved in circuit analysis or troubleshooting electrical systems.

sun18
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Homework Statement


Find the equivalent resistance of the circuit shown below.


Homework Equations


R=\Sigma_{i}R_{i}
1/R=\Sigma_{i}1/R_{i}

The Attempt at a Solution


I'm having a lot of trouble understanding how this circuit can be simplified. All I see is a big short circuit where the only element that matters is R_{4}. What I tried was considering R_{2} and R_{3} as being in parallel, but I still see a short circuit happening. I don't think I understand how short-circuits behave, because I don't think the equivalent resistance is simply R_{4}. Any guidance would be greatly appreciated (also sorry for the terrible drawing)
 

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sun18 said:

Homework Statement


Find the equivalent resistance of the circuit shown below.


Homework Equations


R=\Sigma_{i}R_{i}
1/R=\Sigma_{i}1/R_{i}

The Attempt at a Solution


I'm having a lot of trouble understanding how this circuit can be simplified. All I see is a big short circuit where the only element that matters is R_{4}. What I tried was considering R_{2} and R_{3} as being in parallel, but I still see a short circuit happening. I don't think I understand how short-circuits behave, because I don't think the equivalent resistance is simply R_{4}. Any guidance would be greatly appreciated (also sorry for the terrible drawing)

Hi sun18, Welcome to Physics Forums.

Your intuition is correct; The subnetwork consisting of R1 through R3 is bypassed by the wire running from the top terminal to R4. A short circuit is equivalent to a resistance of zero Ohms, so anything in parallel with it is effectively bypassed (A zero Ohm resistance in parallel with any other resistor value is zero).
 
Thanks so much for the response gneill. I guess I was overthinking it instead of concluding the obvious.
 

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