11. If differential amplifier has a differential gain of 20,000. CMRR = 80 dB, then common mode gain is
    

1. 1. 2

   
   
   

   2. 1

   
   
   

   3. 1 / 2

   
   
   

   4. 0

   
   
   

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   20 log	Ad	= 80
   	Ac

   
   

   ⇒	Ad	= 104
   	Ac

   
   

   ⇒	Ad	= Ac
   	104

   
   

   ⇒ Ac =	2 × 104	= 2
   	104

   
   

   Correct Option: A

   20 log	Ad	= 80
   	Ac

   
   

   ⇒	Ad	= 104
   	Ac

   
   

   ⇒	Ad	= Ac
   	104

   
   

   ⇒ Ac =	2 × 104	= 2
   	104

   
   

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12. In the OP-AMP circuit shown in the given figurs V₀ is given by
    
    

1. 1. 2 V_s

   
   
   

   2. – 2 V_s

   
   
   

   3. 3 V_s

   
   
   

   4. – 3 V_s

   
   
   

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   	V0	=	3R	= 3
   	Vs		R

   
   ⇒ V₀ = 3V_s

   Correct Option: C

   	V0	=	3R	= 3
   	Vs		R

   
   ⇒ V₀ = 3V_s

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13. OPAMP used as a tuned amplifier has the tuned circuit connected
    

1. 1. across input

   
   
   

   2. across series impedance at the input

   
   
   

   3. across feedback impedance Z_f

   
   
   

   4. across output

   
   
   

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   NA

   Correct Option: C

   NA

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14. For the circuit shown in the given figure, assuming ideal diodes, output waveform V₀ will be
    

1. 1. 
      

   
   
   

   2. 
      

   
   
   

   3. 
      

   
   
   

   4. 
      

   
   
   

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   Voltage at OP-AMP output
   V₁ = – 1– 5 sin ωt
   

   At ωt =	π	, V0 = -6 volts
   	2

   
   

   At ωt =	3π	, V0 = 4 volts
   	2

   
   During ‘– ’ ve cycl e of t he waveform, when V_I <– 2V, diode D₂ conducts and V₀ = – 2V
   During ‘+’ ve cycle, when V₁ > 2V, D₁ conducts and V₀ = 2V.

   Correct Option: D

   Voltage at OP-AMP output
   V₁ = – 1– 5 sin ωt
   

   At ωt =	π	, V0 = -6 volts
   	2

   
   

   At ωt =	3π	, V0 = 4 volts
   	2

   
   During ‘– ’ ve cycl e of t he waveform, when V_I <– 2V, diode D₂ conducts and V₀ = – 2V
   During ‘+’ ve cycle, when V₁ > 2V, D₁ conducts and V₀ = 2V.

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15. Out put of the OPAMP shown below will be (assuming it to be ideal)
    
    
    

1. 1. zero
      

   
   
   

   2. – (V₁ – V₂) sin ωt

   
   
   

   3. + (V₁ + V₂) sin ωt
      

   
   
   

   4. – (V₁ + V₂) sin ωt

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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