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The symbol for two - input OR- gate in negative logic is:
  • a)
  • b)
  • c)
  • d)
Correct answer is option 'C'. Can you explain this answer?

Let's assume two inputs be A and B.
and the output is Y.
 
 Using De-Morgan's Law:
 Symbols of various logic gates:
1.) OR Gate:
2.) AND Gate:
3.) NOT Gate:
4.) NOR Gate:
5.) NAND Gate:
6.) XOR Gate:
7.) XNOR Gate:

The minimum number of 2-input NAND gates required to implement a 2-input XOR gate is
  • a)
    4
  • b)
    5
  • c)
    6
  • d)
    7
Correct answer is option 'A'. Can you explain this answer?

Mohit Unni answered
Explanation:
To implement a 2-input XOR gate using 2-input NAND gates, we can use the following logic:

1. Connect the two inputs A and B to two separate NAND gates (N1 and N2).
2. Connect the output of N1 to one input of another NAND gate (N3).
3. Connect the output of N2 to the other input of N3.
4. Connect the output of N3 to the input of another NAND gate (N4).
5. Connect the output of N1 to one input of another NAND gate (N5).
6. Connect the output of N2 to the other input of N5.
7. Connect the output of N4 and N5 to two separate inputs of another NAND gate (N6).
8. The output of N6 is the output of the XOR gate.

Calculation:
We can see that we need a total of 6 NAND gates (N1 to N6) to implement a 2-input XOR gate using 2-input NAND gates. Therefore, the correct answer is option A (4 is not enough and options B and C are too many).

Conclusion:
Thus, the minimum number of 2-input NAND gates required to implement a 2-input XOR gate is 6.

______ is also known as Inverter.
  • a)
    NOT Gate
  • b)
    OR Gate
  • c)
    NAND Gate
  • d)
    AND Gate
Correct answer is option 'A'. Can you explain this answer?

Ravi Singh answered
  • NOT Gate is also known as Inverter
  • The 7404 is a high-speed CMOS Logic Quad NOT Gate.
  • The 7404 is also known as Hex inverter.
  • The contains Six independent NOT gates in one package. T
  • The NOT gate consists of only one input and one output.
  • A NOT gate is used to output the Boolean inverse of the applied input.
  • Hence the name ‘Digital Inverter’ or ‘Inverting buffer’. The most commonly used NOT gate IC is 7404.
  • The symbol  and truth table of NOT gate and a buffer given as 

How many AND and OR gates are required to realise Y = AB + BC + CD?
  • a)
    2,3
  • b)
    2,2
  • c)
    B and D
  • d)
    3,1
Correct answer is option 'D'. Can you explain this answer?

To realise the expression Y = AB + BC + CD, follow these steps to determine the number of AND and OR gates required:
  • Each product term (AB, BC, CD) needs an AND gate to combine the variables:
    • AB needs 1 AND gate.
    • BC needs 1 AND gate.
    • CD needs 1 AND gate.
  • An OR gate is used to sum the outputs of the AND gates:
    • 1 OR gate for combining AB, BC, and CD.
Therefore, you need 3 AND gates and 1 OR gate.
 
 

Identify the logic gate shown in the figure?
  • a)
    XNOR
  • b)
    NAND
  • c)
    NOR
  • d)
    XOR
Correct answer is option 'C'. Can you explain this answer?

Sanya Agarwal answered
NOR GATE:
Symbol:

Truth Table:
Output equation:  
Y=A+B
Output is high only when all inputs are low.
It is a universal gate

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