56. The resonant frequency of the Wein bridge oscillator of given in figure, is
    
    

1. 1. 19597 Hz

   
   
   

   2. 1592.35 Hz

   
   
   

   3. 3120.7 Hz

   
   
   

   4. 4777 Hz

   
   
   

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1. View Hint View Answer Discuss in Forum

   f =	1	=	1	= 3120.7 Hz
   	2πRC		2π(51 × 103)(0.001 × 10-6)

   
   

   Correct Option: C

   f =	1	=	1	= 3120.7 Hz
   	2πRC		2π(51 × 103)(0.001 × 10-6)

   
   

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57. RC network shown in the given figure can provide maximum theoretical phase shift of
    
    

1. 1. 90°

   
   
   

   2. 180°

   
   
   

   3. 270°

   
   
   

   4. 360°

   
   
   

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1. View Hint View Answer Discuss in Forum

   Each section having phase shift of 60°, adding up to 180°

   Correct Option: B

   Each section having phase shift of 60°, adding up to 180°

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58. In a common emitter amplifier, the unbypassed emitter resistance provides
    

1. 1. voltage-shunt feedback

   
   
   

   2. current-series feedback

   
   
   

   3. negative-voltage feedback

   
   
   

   4. positive-current feedback

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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59. Given figure represents ac equivalent circuit of a parallel voltage feedback amplifier stage. If hfe, hfc are h parameters in common emitter and common collector operations respectively at Q , then current gain ( I_o / I_t ) of this stage is
    

1. 1. 	RF
      	RL

   
   
   

   2. h_fe

   
   
   

   3. 	RL
      	RF

      
      

   
   
   

   4. h_fc

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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60. In the single-stage transistor amplifier circuit shown in the given figure, if capacitor C_E is removed, then, ac small-signal midband voltage gain of the amplifier
    
    

1. 1. increases

   
   
   

   2. decreases

   
   
   

   3. is unaffected

   
   
   

   4. drops to zero

   
   
   

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1. View Hint View Answer Discuss in Forum

   
   With C_E, voltage gain
   

   Aυ = -	-hfeRL
   	hie + (1 + hfe)RE

   
   If R_E by passed with capacitor C_E, A_V will increase Hence, after removing C_E mid band voltage gain decreases.

   Correct Option: B

   
   With C_E, voltage gain
   

   Aυ = -	-hfeRL
   	hie + (1 + hfe)RE

   
   If R_E by passed with capacitor C_E, A_V will increase Hence, after removing C_E mid band voltage gain decreases.

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