Resolve Parallel Resistor Error: I Set Rtot = 0.168

You need to use Ohm's Law to find the equivalent resistance of two resistors in parallel: Rtot = (R1*R2)/(R1+R2). In this case, R1 = 0.168⋅(1/Ω) and R2 = 9⋅(A/V). Plugging these values into the formula gives you Rtot = 0.151Ω. This is the correct solution. In summary, the conversation discusses finding the equivalent resistance of two resistors in parallel using Ohm's Law. The individual resistances are given in different units, causing confusion in the solution process. However, by properly converting the units and using the correct formula, the correct answer of
  • #1
amwil
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Homework Statement
Two resistors, R1 and R2, are connected in parallel to a power supply that has voltage V and negligible internal resistance. R2 = 9.00 Ω and the resistance of R1 is not known. For several values of V, you measure the current I flowing through the voltage source. You plot the data as I versus V and find that they lie close to a straight line that has slope 0.168 Ω^−1.
Relevant Equations
V = IR
1/Rtot = 1/R1 +1/R2
Since the slope of the I versus V graph is equal to 1/R, I set Rtot equal to 0.168. So then I subtracted 1/0.168 by 1/9 and got 1/R1 =5.841. I then found R1 equal to 1/5.841 or 0.171 but it said I was wrong. Can someone tell me what I did wrong?
 
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  • #2
amwil said:
1/Rtot = 1/R1 +1/R2
Can someone tell me what I did wrong?
0.168 Ω^−1. is a conductance = I / V.
V / I = 1 / 0.168 = 5.952 Ω

1 / ( 1 / 5.952 - 1 / 9 ) = 17.575 Ω
1 / ( 0.168 - 1 / 9 ) = 17.578 Ω
 
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  • #3
Try again, but everytime you write down a number include it's units. As @Baluncore said it's not 0.168, it's 0.168⋅(1/Ω) = 0.168⋅(A/V). This practice will help in future problems too.

So, in your solution you suggest 1/(9V/A) - 1/(0.168A/V), this doesn't make sense because the units don't match.
 
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FAQ: Resolve Parallel Resistor Error: I Set Rtot = 0.168

1. What does "Resolve Parallel Resistor Error: I Set Rtot = 0.168" mean?

This message indicates that there is an error in the calculation of the total resistance (Rtot) in a parallel circuit, and the value calculated for Rtot is 0.168.

2. Why is it important to resolve this error?

Resolving this error is important because it ensures that the calculated values for resistance, current, and voltage in the circuit are accurate. It also helps to identify any potential issues with the circuit design or measurement equipment.

3. How can I fix the parallel resistor error?

To fix the parallel resistor error, you will need to review your circuit design and calculations to determine where the error may have occurred. Double-check your calculations and make sure all components are connected correctly. You may also need to check the measurement equipment for any malfunctions.

4. Can this error occur in other types of circuits?

Yes, this error can occur in other types of circuits, such as series circuits. In series circuits, the total resistance is calculated differently, so the error message may be different. However, the underlying issue of an incorrect calculation of total resistance can still occur.

5. How can I prevent this error from happening in the future?

To prevent this error from happening in the future, it is important to double-check all calculations and circuit designs before conducting any experiments. Also, regularly calibrating and maintaining measurement equipment can help to minimize the chances of errors occurring.

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