A railway crossing has 4 railway tracks. If a train comes on atleast 1 of the…
2021
A railway crossing has 4 railway tracks. If a train comes on atleast 1 of the tracks, the crossing has to be closed. Which gate can be used to implement this?
- A.
NAND
- B.
NOR
- C.
OR
- D.
AND
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Correct answer: C
An OR gate produces a high output (1) if any of its inputs are high. In this scenario:
Inputs: Each of the 4 railway tracks acts as an input (A, B, C, D). A "1" represents a train detected on that track.
Logic: The output (Y) will be 1 (close the crossing) if track A OR track B OR track C OR track D has a train.
Boolean Expression: Y = A + B + C + D.