Electronics and Communication Engineering - Digital Electronics - Discussion

3. 

An OR gate has 4 inputs. One input is high and the other three are low. The output

[A]. is low
[B]. is high
[C]. is alternately high and low
[D]. may be high or low depending on relative magnitude of inputs

Answer: Option B

Explanation:

In OR any input high means high output.


Sangee said: (Jul 17, 2014)  
If all of the input is 0 then the output is low.

If any one of the input is high output becomes high.

Lata said: (Sep 23, 2014)  
Explain deeply and explain with symbol and property.

Dilip N said: (Feb 13, 2015)  
Inputs Outputs
A | B | C | D | Y
0 | 0 | 0 | 0 | 0
1 | X | X | X | 1
X | 1 | X | X | 1
X | X | 1 | X | 1
X | X | X | 1 | 1

X = don't care value(X = 0/1).

Sgb said: (Nov 23, 2016)  
Output=1.

Harish said: (Nov 25, 2016)  
Suppose, in 4 inputs one input is low remaining 3 are high what is the output?

Manjuladevi said: (Mar 23, 2017)  
@Harish.

The Output is high, because in OR any input is high means output is high.

Anusha said: (Aug 25, 2017)  
Hi, everyone.

Suppose take the four inputs as,
a ,b ,c ,d.
OR is nothing but simply add all the inputs.
They have said that one input is high
So, let us take it as a=1, and 3 of them are 0.
b=c=d=0.
OR operation:
a+b+c+d=1+0+0+0
Now we get 1.

It is the final answer.

Badhshah said: (Jan 6, 2018)  
In the OR operation.

If the two inputs are high then the output is high.
For example:-take two inputs A, B &Output Y.

A B Y
0 0 0
0 1 1
1 0 1
1 1 1


So if the three inputs are high then,

1OR1OR1=. first, do for two inputs 1OR1=1.
And now do for another one with this answer1OR1=1,
1OR1OR1=1.

Haseeb Chaudhry said: (Feb 3, 2018)  
a b c d
1 0 0 0 = 1 for OR gate.

In OR gate even one input high causes high.

Giriii said: (Sep 5, 2018)  
One or more of its inputs are high and to produce high on its output. So, the output is "high". Example:0+0=0, 0+1=1, 1+0=1, 1+1=1.

Nagababu said: (Jan 3, 2020)  
How it's high? Please explain.

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