ISRO | ISRO CS 2014 | Question 26

The output of a tristate buffer when the enable input in 0 is
(A) Always 0
(B) Always 1
(C) Retains the last value when enable input was high
(D) Disconnected state

Answer: (D)
Explanation: Truth table is:

E(Enable)   X(input)     y(output)
0           0,1       Z(disconnected)
1           0               0
1           1               1

Even if x is 0 or 1, that current does not flow (means disconnected) through when enable input is 0.

So, option (D) is correct.
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