Digital Electronics - Logic Gates - Discussion


A 2-input NOR gate is equivalent to a ________.

[A]. negative-OR gate
[B]. negative-AND gate
[C]. negative-NAND gate
[D]. none of the above

Answer: Option B


No answer description available for this question.

M.Naresh said: (Aug 25, 2011)  
Please explain me.

G.V.Narayanan said: (Sep 19, 2011)  
Reason for 2 input NOR gate we apply.

Why this result for AND gate?

Rooh said: (Oct 14, 2011)  
For input seq 00 01 10 11
output of nor is 1 0 0 0
output of and is 0 0 0 1
output of nand is 1 1 1 0

So wich is negegetive AND reffer to here i cant understand.

For me it should be negetive OR... the option A will be the answer then..

If given answer is right then please explain it to me...

Bhargavi said: (Mar 8, 2012)  
Can any one please explain this clearly ?

Ashok said: (Apr 18, 2012)  
Negative and gate means your inputs are inverted to the and gate. So you get a output for (00 01 10 11) is 1 0 0 0. It same as the nor gate output. Ok.

Komal said: (Jun 4, 2012)  
A Negative-AND gate functions same as AND gate with all its inputs inverted

A B -A -B OR(A+B) NOR -AND(-A*-B)
0 0 1 1 0 1 1
0 1 1 0 1 0 0
1 0 0 1 1 0 0
1 1 0 0 1 0 0

From above truth table output of NOR gate and negative AND (Bubbled AND gate) are equal.

Arjun Tehale said: (Oct 7, 2012)  
can any one spell it out properly plz

Viswanath said: (Dec 29, 2012)  
If inverter is placed for the two terminals of the and gate. Then it is nor gate. Then from this we can say that -ve and gate is equivalent to nor gate.

Khyati said: (Oct 25, 2013)  
If we compare truth table of negative AND gate And truth table of NOR gate. Than we can easily understand.

Guruswamy said: (Jan 24, 2014)  
Given inputs are A, B,

Case 1:

For NOR gate output is (A+B)complement.

Case 2 :

For negative and gate output is:

(A complement) * (B complement) = (A+B) complement.

S Kumar Swami said: (Feb 21, 2014)  
In this problem we can solve like also,

At first we have taken 2 input as 1 & 0. In the nor gate the output is 0.

It is equivalent to negative and gate because in and gate we will got 0 as output. So in negative and gate it must be 1.

Hence 2 input-nor gate is equivalent to negative and gate.

Jagadish said: (Jun 16, 2015)  
NOR gate is equivalent to AND gate with its inputs bubbled. Means NOR gate = Inputs bubbled AND gate.

Similarly NAND gate means inputs bubbled or gate.

Nitesh Jain said: (Sep 29, 2015)  
How to Remember?

-1/4AND ===negative==> NOR^-2.

-1/4OR ===negative==> NAND^-2.

-1/4NAND ===negative==> OR^-2.

-1/4NOR ===negative==> AND^-2.

Narottam said: (Jun 1, 2016)  
Why not option C?

Shreyan said: (Jul 6, 2016)  

I got it, Thanks.

An007 said: (Aug 2, 2016)  
NOR = (A + B) compliment.

-ve AND means bubble at the input,= NAND.
A comp + B comp = A.B comp.

Sharath said: (Aug 17, 2016)  
Nice explanation, Thanks to all.

Sudhakar said: (Jun 9, 2017)  
I think Option 'A' is the answer.

Pavan Chowdary said: (Sep 10, 2017)  
Yes, correct explanation @Guruswamy.

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