Concept:
Combinational Circuit: Combinational circuit is a circuit in which we combine the different gates in the circuit, for example, Half adder, Full Adder, Half Subtractor, Full Subtractor, encoder, decoder, multiplexer, and demultiplexer.
→ Half Adder:
Boolean expressions for Sum and Carry (if A and B are the inputs)
Sum = A'B + AB' = ( A ⨁ B)
Carry= AB
→ Full Adder:
Boolean expressions for Sum and Carry (if A, B and C are the inputs)
Sum = A'B'C + A'BC' + AB'C' + ABC
Carry= AB + BC + AC
→ Half Subtractor:
Boolean expressions for Difference and Borrow (if A and B are the inputs)
Difference = A'B + AB' = ( A ⨁ B)
Borrow = A'B
Analysis:
From the given circuit diagram
X = [(A'B)' . (AB')']'
⇒ X = [(A + B') . (A'+B)]' [∵ (AB)' = (A' + B')]
⇒ X = [ AB + A'B']' = ( A ⨀ B)' = ( A ⨁ B)
Y = ( A' + B')' = AB
Obtained boolean expression refers to Half Adder.