1. Magnitude of the gain in the inverting op-amp amplifier circuit shown in the figure be x with switch S₁ open. When switch S₁ is closed, then magnitude of gain becomes
   
   

1. 1. 	x
      	2

      
      

   
   
   

   2. – x
      

   
   
   

   3. 2x

   
   
   

   4. – 2x

   
   
   

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   	Vo	= A =	-2R	= -2 = x
   	Vi		R

   
   When switch S₁ is closed,
   

   A =	-R	= -1 =	x
   	R		2

   Correct Option: A

   	Vo	= A =	-2R	= -2 = x
   	Vi		R

   
   When switch S₁ is closed,
   

   A =	-R	= -1 =	x
   	R		2

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2. The common mode voltage is completely alternated at the out put of the differential amplifier shown in the figure, if
   
   

1. 1. R₁ + R₂ = R₃ + R₄

   
   
   

   2. R₁ – R₂ = R₃ – R₄

   
   
   

   3. 	R1	=	R3
      	R2		R4

   
   
   

   4. 	R2	=	R3
      	R1		R4

      
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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3. In an non-inverting OP-AMP summer is shown in the figure, output voltage V₀ will be
   
   

1. 1. 		3		sin (100t)
      		2

      
      

   
   
   

   2. 3 sin (100t)

   
   
   

   3. sin (100 t)

   
   
   

   4. 2 sin (100 t)

   
   
   

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   V0 = -2		1 +	2R		+ (2 + sin 100 t)		1 +	2R
   			R					R

   
   = – 6 + 6 + 3 sin 100 t = 3 sin 100 t

   Correct Option: B

   V0 = -2		1 +	2R		+ (2 + sin 100 t)		1 +	2R
   			R					R

   
   = – 6 + 6 + 3 sin 100 t = 3 sin 100 t

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4. The circuit connection of OP-AMP given in the Fig. (a) and Fig. (b) represent
   
   

1. 1. logarithmic amplifiers for both Fig. (a) and (b)

   
   
   

   2. detectors for both Fig. (a) and (b)

   
   
   

   3. detectors for Fig. (a) and logarithmic amplifier for figure (b)

   
   
   

   4. logarithmic amplifier for Fig. (a) and detector for Fig. (b)

   
   
   

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   NA

   Correct Option: D

   NA

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5. If I .C. amplifier shown in the figure has an input volt age V_i = 0.1 cos (2π × 100t) volt s, t hen waveform of the output voltage V₀ is
   
   
   

1. 1. 
      

   
   
   

   2. 
      

   
   
   

   3. 
      

   
   
   

   4. 
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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