171. Identify the operation of circuit in negative level logic system—
     

1. 1. AND

   
   
   

   2. OR

   
   
   

   3. NAND

   
   
   

   4. NOR

   
   
   

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1. View Hint View Answer Discuss in Forum

   

   Correct Option: D

   

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172. The value of X. 1 is—

1. 1. X′

   
   
   

   2. X

   
   
   

   3. 1

   
   
   

   4. 0

   
   
   

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1. View Hint View Answer Discuss in Forum

   X 1 = X (X nor) 1 = X·1 + X 1 = X
   Hence alternative (B) is the correct answer.

   Correct Option: B

   X 1 = X (X nor) 1 = X·1 + X 1 = X
   Hence alternative (B) is the correct answer.

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173. Identify the circuit—
     

1. 1. AND

   
   
   

   2. XOR

   
   
   

   3. XNOR

   
   
   

   4. OR

   
   
   

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1. View Hint View Answer Discuss in Forum

   XOR
   
   F1 = AB
   F2 = (ABA)′ = AB + A′
   F3 = (ABB)’ = AB + B′
   Y=F2 F3 = (AB + A′) (AB + B′)′
   = (AB + A′B′)′
   = A′B + AB′
   = X OR gate.
   Hence alternative (B) is the correct answer.

   Correct Option: B

   XOR
   
   F1 = AB
   F2 = (ABA)′ = AB + A′
   F3 = (ABB)’ = AB + B′
   Y=F2 F3 = (AB + A′) (AB + B′)′
   = (AB + A′B′)′
   = A′B + AB′
   = X OR gate.
   Hence alternative (B) is the correct answer.

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174. Match correctly—
     

     Counter	Number of states
     (a) Ripple counter	1. 2N
     (b) Johnson Counter	2. N
     (c) Ring Counter	3. 2N
     (d) Sequence counter	4. 2N – 1

1. 1. (a) (b) (c) (d)
      &nsbp;&nsbp;&nsbp;1&nsbp;&nsbp;&nsbp;3&nsbp;&nsbp;&nsbp;2&nsbp;&nsbp;&nsbp;4

   
   
   

   2. (a) (b) (c) (d)
      &nsbp;&nsbp;&nsbp;1&nsbp;&nsbp;&nsbp;3&nsbp;&nsbp;&nsbp;2&nsbp;&nsbp;&nsbp;1

   
   
   

   3. (a) (b) (c) (d)
      &nsbp;&nsbp;&nsbp;1&nsbp;&nsbp;&nsbp;2&nsbp;&nsbp;&nsbp;3&nsbp;&nsbp;&nsbp;4

   
   
   

   4. (a) (b) (c) (d)
      &nsbp;&nsbp;&nsbp;4&nsbp;&nsbp;&nsbp;1&nsbp;&nsbp;&nsbp;2&nsbp;&nsbp;&nsbp;3

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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175. To realise the given truth table from the circuit shown in figure, the input to J in terms of A and B would be—
     

1. 1. AB

   
   
   

   2. A

   
   
   

   3. B

   
   
   

   4. AB

   
   
   

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1. View Hint View Answer Discuss in Forum

   From truth table if we form K map, we get
   
   J = AB + AB = B (A + A) = B

   Correct Option: C

   From truth table if we form K map, we get
   
   J = AB + AB = B (A + A) = B

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