Question

Truth table for the below logic gate

Answer 1

The expression for this circuit is:

!(!(A&&B) || (B&&C) || (C&&D))

The truthtable is in the picture below.

Step-by-step explanation:

To make the output high, all inputs for the NOR gate must be low. For that, A and B must be high, there is no other way.

That implies that C must be low, to make the second AND gate low.

Finally, input D doesn't play a role in the output.