231. The purpose of comparator is to:

1. 1. amplify an input voltage.

   
   
   

   2. detect the occurrence of a changing input voltage

   
   
   

   3. maintain a constant output when the dc input voltage changes.

   
   
   

   4. produce a constant output when an input voltage equals the reference voltage.

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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232. The voltage gain of a voltage follower:

1. 1. unity

   
   
   

   2. less than unity

   
   
   

   3. greater than unity

   
   
   

   4. variable

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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233. Which of the following characteristics do not necessarily apply to the op-amp?

1. 1. high gain

   
   
   

   2. high power

   
   
   

   3. high input impedance

   
   
   

   4. low output impedance

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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234. For a given circuit, the value of V_o and A_CL is:
     
     
     

1. 1. 5 V and 1

   
   
   

   2. 5 V and 5

   
   
   

   3. 0 V and 1

   
   
   

   4. 0 V and 5

   
   
   

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1. View Hint View Answer Discuss in Forum

   The given circuit represents voltage follower. So,
   V_o = V_in = V₊ = 5 V.
   Since R_f = 0.
   so feedback factor.
   β = 0
   A_OL = 1 (open loop gain)
   

   Now, ACL =	ACL	=	1	= 1
   	1 + AOLβ		1 + 0

   
   Hence alternative (A) is the correct choice.

   
   

   Correct Option: A

   The given circuit represents voltage follower. So,
   V_o = V_in = V₊ = 5 V.
   Since R_f = 0.
   so feedback factor.
   β = 0
   A_OL = 1 (open loop gain)
   

   Now, ACL =	ACL	=	1	= 1
   	1 + AOLβ		1 + 0

   
   Hence alternative (A) is the correct choice.

   
   

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235. The maximum allowable value of V_in for circuit given below. Given gain of the amplifier is 200
     
     
     

1. 1. 400 mV

   
   
   

   2. 40 mV

   
   
   

   3. 4 V

   
   
   

   4. 4000 mV

   
   
   

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1. View Hint View Answer Discuss in Forum

   Given that
   V_o = 8 V
   A = 200
   V_in =?
   

   Vo = Vin		–	20 × 103
   			100

   
   

   or Vin =	8	= 40 mV
   	200

   
   

   Correct Option: B

   Given that
   V_o = 8 V
   A = 200
   V_in =?
   

   Vo = Vin		–	20 × 103
   			100

   
   

   or Vin =	8	= 40 mV
   	200

   
   

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