How Are These Resistors in Parallel

In summary, the output resistance of a voltage divider is the sum of the resistances of the individual resistors in the divider.
  • #1
FAS1998
50
1
I’ve included an image of a solution to a problem from my textbook. Part of the problem is to find the equivalent resistance of the given circuit. In the solution they seem to be treating the resistors as if they were in parallel. I don’t understand why they are doing this.

For the two resistors to be in parallel would they not need to have both nodes in common? The resistors in the series don’t appear to have this property.

[Moderator's note: Moved from a technical forum and thus no template.]
 

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  • #2
FAS1998 said:
I’ve included an image of a solution to a problem from my textbook. Part of the problem is to find the equivalent resistance of the given circuit. In the solution they seem to be treating the resistors as if they were in parallel. I don’t understand why they are doing this.

For the two resistors to be in parallel would they not need to have both nodes in common? The resistors in the series don’t appear to have this property.

[Moderator's note: Moved from a technical forum and thus no template.]
It might clarify matters if you post the whole question.
 
  • #3
haruspex said:
It might clarify matters if you post the whole question.
Here’s the original question. It states that the circuit is a voltage divider, which I believe implies that the resistors are in series, and then the solution uses the equation for resistors in parallel to calculate the equivalent resistance.

I’ve seen similar things elsewhere in the textbook solutions so I assume I’m doing something wrong, and it’s not just a mistake in the solution.
 

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  • #4
FAS1998 said:
Here’s the original question. It states that the circuit is a voltage divider, which I believe implies that the resistors are in series, and then the solution uses the equation for resistors in parallel to calculate the equivalent resistance.

I’ve seen similar things elsewhere in the textbook solutions so I assume I’m doing something wrong, and it’s not just a mistake in the solution.
The key is the meaning of "equivalent output resistance".
See if the answer given here helps:
https://electronics.stackexchange.com/questions/265800/voltage-divider-output-resistance?rq=1
 

Related to How Are These Resistors in Parallel

What is the definition of parallel resistors?

Parallel resistors are two or more resistors that are connected side by side, allowing the current to split and flow through each resistor separately.

How do you calculate the total resistance of resistors in parallel?

The total resistance of resistors in parallel can be calculated using the formula 1/R(total) = 1/R1 + 1/R2 + 1/R3 + ..., where R1, R2, R3, etc. are the resistance values of each individual resistor.

What is the effect of adding resistors in parallel?

Adding resistors in parallel decreases the total resistance of the circuit, as the current has multiple paths to flow through instead of just one. This can also increase the total current in the circuit.

What are the advantages of using parallel resistors?

Some advantages of using parallel resistors include: increasing the total current in the circuit, allowing for fine-tuning of resistance values, and providing redundancy in case one resistor fails.

What are some real-life applications of resistors in parallel?

Resistors in parallel are commonly used in household appliances, electrical circuits, and electronic devices. They can also be found in voltage regulators, light dimmers, and audio systems.

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