Consider a digital logic circuit consisting of three 2-to-1 multiplexers M1, M2, and M3 as shown below. X1 and X2 are inputs of M1. X3 and X4 are inputs of M2. A, B, and C are select lines of M1, M2, and M3, respectively. For an instance of inputs X1=1, X2=1, X3=0, and X4=0, the number of

Question

Consider a digital logic circuit consisting of three 2-to-1 multiplexers M1, M2, and M3 as shown below. X1 and X2 are inputs of M1. X3 and X4 are inputs of M2. A, B, and C are select lines of M1, M2, and M3, respectively. For an instance of inputs X1=1, X2=1, X3=0, and X4=0, the number of combinations of A, B, C that give the output Y=1 is

Accepted Answer

4. The output Y=1 can occur when M1 selects either X1 or X2 (both are 1), and M2 selects either X3 or X4 (both are 0). Since M3's selection does not affect the output when M2 outputs 0, there are 4 combinations of A, B, and C that can yield Y=1.

Solution

Related GATE Technical questions