Write the Boolean expression and construct the truth table for the function y of A and B in Fig.

Explanation

In the given circuit, the gate I is NOR gate and gate II is NAND gate.
The output of NOR gate, `y^(')=bar(A+B)`
The output of `NAND` gate, `y=bar(A.y^('))`
`:. y=barA+bar(y^('))=barA+bar(bar(A+B))=barA+A+B=1+B`
`[ :' bar(bar(A+B))=A+B and A+barA=1]`
The truth table for this combination of gates is shown below:
`|{:(A,B,bar(A+B),A.bar(A+B),bar(A.bar(A+B))),(0,0,1,0.1=0,1),(1,0,0,1.0=0,1),(0,1,0,0.1=0,1),(1,1,0,1.0=0,1):}|`