Finding current in a combined circuit

[Jennifer_ea]

Homework Statement

We are given the following diagram:

And the values R1 = 13.0 Ω, R2 = 84.0 Ω, and R3 = 18.0 Ω
VAB = 110.0 V

I have previously solved for Req of 69.5 Ω

Homework Equations

V=IR

The Attempt at a Solution

I have found Req for the circuit to the right of A-B (992/11 Ω)

My first try I'm really not sure what I did but got 1 A. I must have made an error somewhere for that one.

For the second try I used the 1 A I got from... somewhere and found that the AB section is 48.2% of the load, and used 0.482 A for the answer. Basically I was flailing around and wasted my chances.

I only have one try left, and this is what I've done so far:

I searched around the forum and found information about this table method.
First I used the series way, having CD Req (R2) and leaving the two 13 Ω resistors (R1 and R3) closest to the beginning.
--| -R1- | --R2-- | --R3-- | T
--|-------|--------|--------|---------
E |2.246 | 7.511 | 2.246 | 12
I | 0.173 | 0.173 | 0.173 |
R| 13 ---| 43.5 -| 13 --- |

I then took the R2 section and split it into CD and Req for the circuit to the right and did it again for parallel
--| -CD- | --Req--- | T
--|---------|---------|--------
E |7.511 --| 7.511 -|
I | 0.0894 | 0.0839 | 0.173
R| --84 ---| 992/11 |

I think this gives me a current of 0.0894 A through CD, but I'm not confident I'm using these tables correctly. Am I allowed to combine like I have?

Thanks for your help!

 

[mark726]

Hello,

Thank you for sharing your approach to solving this circuit problem. It seems like you have made some progress by using the table method. However, I would suggest double-checking your calculations and making sure that you are using the correct values for each resistor.

To answer your question about combining resistors in the table, yes, you are allowed to combine them if they are in series or in parallel. Just make sure to label the combined resistor with the appropriate equivalent value.

Also, I noticed that you have not used the given voltage value (VAB = 110.0 V) in your calculations. Remember that you can use Ohm's law (V=IR) to calculate the current in each section of the circuit.

I would suggest going through your calculations again and checking for any errors. If you are still having trouble, you can try using a different method, such as the loop or node analysis method, to solve the circuit. Don't be afraid to ask for help or clarification if needed.

Good luck with your final try!