The following is the AB flip flop:
What are values of A, B when change in the flip flop state is from 0 to 1 ?
Note: x in the options below represents that it can have any value out of 0 and 1.
(A) 1, x
(B) 0, x
(C) 1, 0
(D) x, 1
Answer: (B)
Explanation: Characteristic equation => Qn = A′.Q′ + B′.Q
To change from 0->1 means Q = 0 and Qn = 1
Thus
1 = A’(1) + B’(0) = A’
Hence , A = 0 and B can have 0 or 1 not matters.