31. Which of the following circuit constitute an oscillator:

1. 1. Monostable multivibrator

   
   
   

   2. Astable multivibrator

   
   
   

   3. Bistable multivibrator

   
   
   

   4. Schmitt trigger

   
   
   

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   NA

   Correct Option: D

   NA

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32. The shorter interval between pulses permitting a binary to switch from one state to another is:

1. 1. Delay time

   
   
   

   2. Rise time

   
   
   

   3. Resolving time

   
   
   

   4. Relaxation time

   
   
   

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   NA

   Correct Option: A

   NA

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33. The voltage regulation is ........... in an excellent power supply

1. 1. zero

   
   
   

   2. large

   
   
   

   3. infinity

   
   
   

   4. negative

   
   
   

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   NA

   Correct Option: A

   NA

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34. 63. The zener diode in the current shown in figure (A) has the characteristics shown in figure (B). If R₂ is the lowest load resistance to be used for regulated supply. Then to get load regulation, R₁ must be:
    
    
    
    

1. 1. greater than	V0 + 0·01R2
      	(Vin – V0)R2

   
   
   

   2. greater than	(Vin – V0)R2
      	V0 – 0·01R2

   
   
   

   3. less than	(Vin – V0)R2
      	V0 + 0·01R2

   
   
   

   4. less than	V0 + 0·01R2
      	(Vin – V0)R2

   
   
   

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   Given that I_{z (max)} = 10 mA
   

   and from figure IL =	V0
   	R2

   
   Now, for good load regulation

   
   

   Correct Option: C

   Given that I_{z (max)} = 10 mA
   

   and from figure IL =	V0
   	R2

   
   Now, for good load regulation

   
   

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35. The small signal voltage gain AV =	V0	is:
    	VS

1. 1. – 4.38

   
   
   

   2. 4.38

   
   
   

   3. – 1.88

   
   
   

   4. 1.88

   
   
   

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   AV =	V0	= – gm. Rc.		rπ
   	VS			rπ + RB

   
   

   = – 24 × 10– 3. 4 × 103		5 × 103
   		5 × 103 + 250 × 103

   
   

   = – 120 ×	5	= – 1.88
   	255

   Correct Option: C

   AV =	V0	= – gm. Rc.		rπ
   	VS			rπ + RB

   
   

   = – 24 × 10– 3. 4 × 103		5 × 103
   		5 × 103 + 250 × 103

   
   

   = – 120 ×	5	= – 1.88
   	255

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