# Electronics and Communication Engineering - Digital Electronics - Discussion

Discussion Forum : Digital Electronics - Section 1 (Q.No. 3)
3.
An OR gate has 4 inputs. One input is high and the other three are low. The output
is low
is high
is alternately high and low
may be high or low depending on relative magnitude of inputs
Explanation:

In OR any input high means high output.

Discussion:
12 comments Page 1 of 2.

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.

Anusha said:   6 years ago
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.

(1)

Dilip N said:   9 years ago
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).

Giriii said:   5 years ago
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.
(1)

Sangee said:   10 years ago
If all of the input is 0 then the output is low.

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

@Harish.

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

Harish said:   7 years ago
Suppose, in 4 inputs one input is low remaining 3 are high what is the output?

HASEEB CHAUDHRY said:   6 years ago
a b c d
1 0 0 0 = 1 for OR gate.

In OR gate even one input high causes high.

Ravi singh said:   2 years ago
@All.

Can anyone explain all gate input and output when its high or low?

Lata said:   9 years ago
Explain deeply and explain with symbol and property.