Solving a Circuit: Neglecting the 1 Ohm Resistor

In summary, the conversation discusses the disregard of a 1 ohm resistor in a problem and finding the equivalent resistance of 6 and 3 ohms. It is mentioned that the current through the resistor is unknown and if it is zero, the resistor can be removed without affecting the circuit. The conversation concludes with an understanding and appreciation for the explanation.
  • #1
Neon32
68
1
I want to know why in this problem in the solution, he disregarded the 1 ohm resistor and found the equivalent resistance of 6 and 3 ohms right away.

https://imgur.com/a/efG11
 
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  • #2
What is the current through that resistor? What does that tell you about the voltage drop across it?
 
  • #3
Nugatory said:
What is the current through that resistor? What does that tell you about the voltage drop across it?

I don't know the current through that resistor. Actually I don't know the current on any of the resistors so I'm not sure what you are trying to say.
 
  • #4
Current has to come from someplace and go to another. If there was current in the 1 ohm resistor, where would it go?
 
  • #5
anorlunda said:
Current has to come from someplace and go to another. If there was current in the 1 ohm resistor, where would it go?
it will go to V0. there is a voltage V0
 
  • #6
No, you are misinterpreting the diagram. Those circles at the ends of the wires near V0 depict the terminals of an open circuit. Zero current goes to V0.
 
  • #7
anorlunda said:
No, you are misinterpreting the diagram. Those circles at the ends of the wires near V0 depict the terminals of an open circuit. Zero current goes to V0.
So you mean if the current doesn't go anywhere after passing through the resistor so we disregard it? we consider the current is equal 0?
 
  • #8
Neon32 said:
So you mean if the current doesn't go anywhere after passing through the resistor so we disregard it? we consider the current is equal 0?

Yes. If we know the current in the resistor is zero, then the resistor can be removed or ignored without changing the circuit.
 
  • #9
Neon32 said:
So you mean if the current doesn't go anywhere after passing through the resistor so we disregard it?
anorlunda said:
Yes. If we know the current in the resistor is zero, then the resistor can be removed or ignored without changing the circuit.
Got it. Thank you, appreciated.
 

Related to Solving a Circuit: Neglecting the 1 Ohm Resistor

1. What is the purpose of neglecting the 1 Ohm resistor in a circuit?

The purpose of neglecting the 1 Ohm resistor is to simplify the circuit and make calculations easier. In some cases, the 1 Ohm resistor may have a negligible effect on the overall circuit behavior, so it can be safely ignored without significantly impacting the accuracy of the solution.

2. When can we neglect the 1 Ohm resistor in a circuit?

The 1 Ohm resistor can be neglected when the resistance of the other components in the circuit is much larger than 1 Ohm. This can be determined by calculating the equivalent resistance of the circuit using Ohm's law.

3. What are the consequences of neglecting the 1 Ohm resistor?

Neglecting the 1 Ohm resistor can result in a slightly less accurate solution for the circuit. It may also affect the power dissipation and voltage drops across the other components in the circuit.

4. How does neglecting the 1 Ohm resistor affect the current in the circuit?

Neglecting the 1 Ohm resistor does not affect the current in the circuit, as long as the other components have significantly higher resistance. The current will still flow through the circuit in the same manner.

5. Can we always neglect the 1 Ohm resistor in a circuit?

No, we cannot always neglect the 1 Ohm resistor in a circuit. It depends on the specific components and their values in the circuit. If the 1 Ohm resistor has a significant effect on the overall behavior of the circuit, it should not be neglected.

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