# Help in a circuit

Discussion in 'Homework Help' started by luigihs, Oct 10, 2012.

1. ### luigihs Thread Starter New Member

Oct 10, 2012
12
0
Hi Im trying to figure this circuit

I already got the total current that I did doing the Delta / star . what I got is 4.06 for total current, now is asking me to get the current of R1 , I know I have to get the voltage in order to get the current that is I = V/R but I dont have any idea how to get the voltage when is parallel im lost somebody can help me please!

Oct 10, 2012
12
0
Anyone ?

3. ### justtrying Active Member

Mar 9, 2011
329
405
the calculations for this circuit work out very nicely. You should get a round number for your total current, from there on, if you are using conversion, you have to work backwards to calculate currents through the legs. Current divider rule is handy. I think that mesh analysis is easier when solving these problems when they are not so nicely set up.

1. you may have made a slight mistake during conversion, as I total is slightly off
2. apply current divider to figure out current through R1

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4. ### mlog Member

Feb 11, 2012
276
36
This problem screams, "Use mesh analysis!"

5. ### WBahn Moderator

Mar 31, 2012
18,087
4,917
I agree -- mesh current is the way to go. Doing the delta-wye transforms is valid and will work, but I think the effort involved in doing the transformations (plus the resulting parallel reductions that follow) is more than the effort of doing the mesh current analysis, especially since the latter will yield the information you need to answer the follow-up questions directly.

6. ### justtrying Active Member

Mar 9, 2011
329
405
These problems are definitely to be solved by mesh analysis - simple and effective - but I have a feeling that the OP has not been exposed to it yet...

7. ### WBahn Moderator

Mar 31, 2012
18,087
4,917
Then hopefully the OP will say so and we can find out what the relevant background is and go from there. But I know that I got mesh, nodal, superposition, and source transformations before I got delta-wye conversions.

8. ### Dodgydave AAC Fanatic!

Jun 22, 2012
5,155
772
Total resistance is, 1R in parallel with 5.5R = 0.846R

so total resistance is 2.4R+2R+0.846R=5.24R

voltage drop across R1= 0.846/5.24 X 16V =2.58V

so current is 2.58Amps

Last edited: Oct 13, 2012
9. ### The Electrician AAC Fanatic!

Oct 9, 2007
2,301
338
You have ignored the effect of the 3Ω resistor.