Question

For the device shown here, assume the D input is LOW, both S inputs are LOW and the input is LOW. What is the status of the Y’ outputs?

(a) All are HIGH

(b) All are LOW

(c) All but Y0 are LOW

(d) All but Y0 are HIGH

The question was asked in quiz.

Question is from Combinational Circuits in section Combinational Circuits of Digital Circuits

Answer 1

The correct answer is (d) All but Y0 are HIGH

The best explanation: In the given diagram, S0 and S1 are selection bits. So,

I/P S0 S1 O/P

D = 0 0 0 Y0

D = 0 0 1 Y1

D = 0 1 0 Y2

D = 0 1 1 Y3

Hence, inputs are S0 and S1 are Low means 0, so output is Y0 and rest all are HIGH.