Question

The equivalent resistance between A and B is ​

Answer 1

Answer:

This is a case, which I call it Double Wheatstone Bridge.(although it's not, actual one is Kelvin's bridge)

I do that just for Memorizing.

So, what you have to do is just remove the two resistances that divides the square of resistance into two.

OR a more logical explanation,

Consider the upper two boxes of the AB line, that makes it one Wheatstone bridge. So Resistance in between cancelled.

Similarly the lower two boxes of of the AB line,that makes it one Wheatstone bridge. So Resistance in between cancelled again.

So, you are left with, the upper branch, the middle branch and the lowest branch, all of them in parallel.

Equivalence comes out to be, 1Ω.

Refer attachment with steps for clarity!

Actually the computer uploaded it randomly, sequence:

3-->1-->4-->2.