Consider the following logic circuit. [figure] The output is Y = 0 when :
- A = 1 and B = 0
- A = 0 and B = 0
- A = 1 and B = 1
- A = 0 and B = 1
Answer
(3) A = 1 and B = 1
Solution
Output of the AND gate: Y1 = A B
Inputs of the OR gate are B and A: Y2 = B + A
Final NAND gate: Y = Y1 Y2
Y = 0 only when Y1 = 1 and Y2 = 1
Y1 = 1 A = 1 and B = 1; then Y2 = 1 + 0 = 1 ✓
Y = 0 when A = 1 and B = 1.
Answer: (3)