# find equivalence resistance....

Discussion in 'Homework Help' started by gaurav1292, Oct 1, 2009.

1. ### gaurav1292 Thread Starter New Member

Oct 1, 2009
12
0

calculate d equivalent resistance b/w d terminals of d cell. d resistance of each quadrant 1.e blue one is 1 ohm and that of intersecting diameter i.e green one is 2 ohm.

i tried by distributing current in various branch but was not successful. plz tell me a way to solve this problem.

2. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
783
I did it by re-drawing the circuit in a clearer format.

Then I used delta-star transformations to reduce the network to a form where simple series-parallel rules can be applied.

I calc Rtot seen by source is 2.6471 Ω

3. ### syed_husain Active Member

Aug 24, 2009
61
5
hi, tnk,

i tried to solve with mesh equations. i got the same answer but the problem is it i had to solve 4 equations with 4 unknown. i tried 2 use thevemin but failed. could u pls tell me how did u do delta-Y transform?

thnx.

Last edited: Oct 1, 2009
4. ### Tesla23 Active Member

May 10, 2009
323
67
Draw a line of symmetry through it at 45° then the resistance is

2 * (0.5 + 2||(1 + 2||0.5)) = 45/17 = 2.6471

where a||b = ab/(a+b) - parallel resistors

5. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
783
Hi Syed,

Tesla123's method is clearly the most elegant and succinct.

If you are not sure how he did it and/or are still interested in my longer method I have included an attachment.

File size:
41.4 KB
Views:
25
6. ### syed_husain Active Member

Aug 24, 2009
61
5
tesla23 and tnk, thank u very much 4 ur help. i really appreciate it.

Syed

7. ### gaurav1292 Thread Starter New Member

Oct 1, 2009
12
0
thanks for ur help!!!!!!!!!!!