# Digital Electronics - Boolean Algebra and Logic Simplification - Discussion

Discussion Forum : Boolean Algebra and Logic Simplification - General Questions (Q.No. 41)
41.
An OR gate with schematic "bubbles" on its inputs performs the same functions as a(n)________ gate.
NOR
OR
NOT
NAND
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
4 comments Page 1 of 1.

Umesh chander said:   8 years ago
Question is saying "bubbles" on its inputs.

So inputs to the OR gate is now A' and B' and the on the addition of A'+B' will get the output as NAND gate i.e.

A B A' B' A'+B'
0 0 1 1 1
0 1 1 0 1
1 0 0 1 1
1 1 0 0 0

PRITHA said:   7 years ago
According to Demorgan's 1st theorem,

(A.B)'=A'+B'.
Here, the input of the OR gate becomes,
A',B' as it is passed through the bubble before applied to the gate . Thus the output becomes
A'+B' which gives (A+B)' by De morgan's theorem which is the output of NAND gate.

Steven said:   1 decade ago
why is it a NOR gate. Shouldn't a nor gate be (A+B)(bar) while the and gate has A(bar) + B(bar)?

Saurav said:   9 years ago
The answer should be Option (A) NOR.

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