Current in circuit with many resistors

In summary: He wanted you to combine the two drawings into one so that the parallel resistors are more visible. After doing that, you can then use the BvU formula to find the resistance.
  • #1
miyayeah
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0

Homework Statement


Find the current and potential difference through 3Ω resistor.

Homework Equations


ε - I1 (Ω) - I2 (Ω) ... = 0

The Attempt at a Solution


I only got as far as finding the equation:
ε - I1 (3Ω) - I2 (16Ω) = 0 (For complete loop around circuit)
I know I have to find I1, but I don't know the value of I2 too, so I'm not sure how I need to start the question.

This is due midnight, any help would be appreciated.
 

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  • #2
Why don't you try simplifying the circuit first. Can you think of what you can do with the other resistors (4Ω, 48Ω, 16Ω)?
 
  • #3
When you compare the voltages over the 3, 16 and 48 ohm resistors, what do you notice ?
Can you redraw the diagram so it looks more familiar ?
 
  • #4
Can you identify some resistors in parallel? Do you know how to calculate the effective resistance of the set?
 
  • #5
hehe...
 
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  • #6
haruspex said:
Can you identify some resistors in parallel? Do you know how to calculate the effective resistance of the set?
I believe 4Ω and 48Ω resistors are in parallel.
Req = (1/R1 + 1/R2 +...) -1.
But how would this help solve the problem?

BvU said:
When you compare the voltages over the 3, 16 and 48 ohm resistors, what do you notice ?
Can you redraw the diagram so it looks more familiar ?
I tried drawing it in two different parts, but I'm not sure how to combine the two, if they are right.

28081223_752792301578449_127912078_o.jpg
 

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  • #7
miyayeah said:
I believe 4Ω and 48Ω resistors are in parallel.
They are indeed in parallel. Is there another resistor nearby that could also be considered in parallel with the 4Ω and 48Ω?
miyayeah said:
Req = (1/R1 + 1/R2 +...) -1.
But how would this help solve the problem?
If you can find the Req as seen by the voltage source, finding the current becomes easy. And if you know the current going through the 3Ω, finding the voltage across it becomes easy. Recognizing the parallel resistors is the first step.
miyayeah said:
I tried drawing it in two different parts, but I'm not sure how to combine the two, if they are right.
BvU was asking you to redraw your original circuit so that the parallel resistors would be more obvious. Drawing those two circuits, as you did, is not what he had in mind.
 
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1. What is current in a circuit with many resistors?

The current in a circuit with many resistors refers to the flow of electric charge through the circuit. It is measured in amperes (A) and is dependent on the voltage applied and the resistance of the circuit.

2. How is current affected by resistors in a circuit?

The presence of resistors in a circuit will affect the flow of current. This is because resistors create a resistance to the flow of electric charge, which in turn decreases the amount of current flowing through the circuit.

3. What is the relationship between current and resistance in a circuit with many resistors?

According to Ohm's Law, the current in a circuit is directly proportional to the voltage and inversely proportional to the resistance. This means that as the resistance increases, the current decreases and vice versa.

4. How can current be calculated in a circuit with many resistors?

To calculate the current in a circuit with many resistors, you can use Ohm's Law (I=V/R) or Kirchhoff's Current Law which states that the total current entering a junction is equal to the total current leaving the junction.

5. What factors can affect the current in a circuit with many resistors?

The current in a circuit with many resistors can be affected by various factors such as the voltage applied, the resistance of the circuit, the type of material used for the resistors, and the temperature of the circuit. Other external factors such as humidity and pressure can also affect the flow of current.

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