Calculate the equivalent resistance of the network across the points A and B shown in figure.
Here in this diagram, say:
R1 = 4Ω
R2 = 8Ω
R3 = 4Ω
R4 = 8Ω
When we want to find the resistance across points A and B then resistance R1 and R2 are connected in series and resistances R3 and R4 are also connected in series.
Thus,
R5 = R1 + R2 = 4Ω + 8Ω = 12Ω
And, R6 = R3 + R4 = 4Ω + 8Ω = 12Ω
Now, this R5 and R6 are connected to each other in parallel. Thus the equivalent resistance RAB across points A and B is: