Electronics and Communication Engineering - Digital Electronics - Discussion


An AND gate has two inputs A and B and one inhibit input 3, Output is 1 if

[A]. A = 1, B = 1, S = 1
[B]. A = 1, B = 1, S = 0
[C]. A = 1, B = 0, S = 1
[D]. A = 1, B = 0, S = 0

Answer: Option B


All AND inputs must be 1 and inhibit 0 for output to be 1.

Tharun said: (May 19, 2014)  
What is inhibit?

Vinay said: (Aug 16, 2014)  
When a digital "on" signal is present at a particular input (known as the inhibit input) to the logic circuit, the logical output from the logic circuit is blocked; and when the inhibit input signal is absent, the logical output from the logic circuit is affected only by signals at the remaining inputs.

Thus the answer is B.

Smjr said: (Aug 4, 2016)  
Is inhibit is the opposite of enable?

Akshay said: (Sep 21, 2016)  
Inhibit input is just as the third input to AND gate which is given through not gate as an input so,
When inputs are :- A * B * S(bar) = 1 * 1 *0 (bar).
Then output will be 1.

Joemad said: (Sep 24, 2016)  
It is basically an AND gate which has one of its inputs negated by an inverter. The input which is negated acts to inhibit the gate. Or we can say the gate will behave like an AND gate only when the negated input is set at a logic level '0'. Now we will see this through the circuit symbol and truth table for a four input INHIBIT gate.

Arjun Krishna Dev said: (Apr 21, 2018)  
Nice explanation, thanks @Akshay.

Bingi Sainath said: (Oct 12, 2018)  
Nice explanations. Thanks all.

Rabas said: (Apr 1, 2020)  
Since we are applying logic'0' to NOT gate the input to the AND gate should be logic '1'right.

So, here now all the inputs are logic '1' so, how s=0?

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