NCERT Class XII Chapter
Semiconductor Electronics
Questions With Solutions
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Question : 18
Total: 19
Write the truth table for circuit given in figure below consisting of NOR gates and identify the logic operation (OR, AND, NOT) which this circuit is performing.
(Hint: A = 0, B = 1 then A and B inputs of second NOR gate will be 0 and hence Y = 1. Similarly work out the values of Y for other combinations of A and B. Compare with the truth table of OR, AND, NOT gates and find the correct one.)
(Hint: A = 0, B = 1 then A and B inputs of second NOR gate will be 0 and hence Y = 1. Similarly work out the values of Y for other combinations of A and B. Compare with the truth table of OR, AND, NOT gates and find the correct one.)
Solution:
Let us find the Boolean expression for the logic circuit.
So, output Y =
(
)
Hence, the output of given logic circuit shows that logic circuit act as OR gate.
Truth Table
So, output Y =
Hence, the output of given logic circuit shows that logic circuit act as OR gate.
Truth Table
| First NOR gate | Second NOR gate | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| A | B | A + B | X = | A = X | B = X | Y = | ||||
| 0 | 0 | 0 | 1 | 1 | 1 | 0 | ||||
| 0 | 1 | 1 | 0 | 0 | 0 | 1 | ||||
| 1 | 0 | 1 | 0 | 0 | 0 | 1 | ||||
| 1 | 1 | 1 | 0 | 0 | 0 | 1 | ||||
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