Calculating Current in Parallel Resistor Circuit

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Discussion Overview

The discussion centers around calculating the current in a parallel resistor circuit involving two batteries with different voltages and a resistor positioned between them. Participants explore the implications of battery configurations, internal resistances, and the potential for infinite current in ideal scenarios.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant describes a circuit with two batteries arranged in parallel with a resistor, questioning how to calculate the current through the resistor given the configuration.
  • Multiple participants request a diagram to better visualize the circuit, indicating difficulty in understanding the verbal description.
  • Concerns are raised about the need for knowing the internal resistance of the batteries to accurately calculate the current.
  • Another participant suggests that if the batteries are ideal, the circuit may lead to conflicting potentials, making the problem unsolvable or indicating a possible error in the diagram.
  • One participant asserts that the diagram is correct and questions what else occurs in the circuit aside from it being shorted.
  • A later reply proposes that if the internal resistance of the batteries is known, the current through the resistor can be determined, but warns that ideal batteries could lead to infinite current circulation.
  • Another participant elaborates on the behavior of real batteries, noting that they behave as if they have internal resistance, which varies with conditions, and suggests that knowing this resistance could allow for solving the circuit.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the circuit's solvability and the role of internal resistance, with no consensus reached on how to proceed with the calculations or the implications of the circuit configuration.

Contextual Notes

Participants highlight the importance of internal resistance in calculations, and there are unresolved questions about the circuit's configuration and the assumptions regarding ideal versus real batteries.

casanova2528
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v1 of battery1 is higher than v2 of battery2

The circuit is arranged in a parallel way with 3 layers where the only
Resistor is in the middle layer.
battery1 is on the top layer and the only resistor is on middle layer
Battery2 is on bottom layer.
The terminals of the battery is not facing each other.It appears like the batteries are arranged in series, but
It is not! How does one calculate the current on resistor?
Does all the current from battery1 skip the resistor on the middle layer
And go to the negative terminal of the battery2 on third level?
 
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Can you post a diagram? I can't picture this circuit from the verbal description.
 
redbelly98 said:
can you post a diagram? I can't picture this circuit from the verbal description.

|----1(+ -)----|
|-----R1-------|
|----2(- +)----|there it is. battery 1 has a higher emf than battery 2. how does one figure out the current through resistor1?
 
You have to know the internal resistance of the batteries.
 
Something is wrong here. It could be we need to know the batteries' internal resistance, as The Electrician said.

Or (if we assume ideal batteries with zero resistance) 2 points that must be at different potentials (because of the batteries) must also be at the same potential (because they are shorted together). That makes the problem unsolveable, or suggests the diagram is incorrect.
 
Redbelly98 said:
Something is wrong here. It could be we need to know the batteries' internal resistance, as The Electrician said.

Or (if we assume ideal batteries with zero resistance) 2 points that must be at different potentials (because of the batteries) must also be at the same potential (because they are shorted together). That makes the problem unsolveable, or suggests the diagram is incorrect.

the diagram is correct. it is a diagram that i made from another problem that was solvable. I was wondering if this diagram is solvable. the batteries are ideal.

so, what else happens beside the circuit being shorted?
 
Last edited:
there must be a way to figure out the small amount of current through resistor1.
 
If you know the internal resistance of the batteries, then you can figure out the current through the resistor.

In the conceptual diagram you gave, the batteries are mathematically ideal. If you connect them as shown, then an infinite current will circulate in the batteries and the current in the resistor will be indeterminate.

Imagine if a small resistor were in series with each battery. Then the circuit could be easily solved. Real batteries do in fact behave as if there were a small resistor inside them; its value changes with temperature and state of charge of the batteries. But if you can get an approximate value for the internal resistance, then you can solve the network.
 

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