116. Class AB operation is often used in power (large signal) amplifiers in order to
     

1. 1. get maximum efficiency

   
   
   

   2. remove even harmonics

   
   
   

   3. overcome a cross-over distortion

   
   
   

   4. reduce collector dissipation

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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117. A signal may have frequency components which lie in the range of 0.001 Hz to 10Hz. which of the following types of coupling should be chosen in a multistage amplifier designed to amplify this signal ?
     

1. 1. RC coupling

   
   
   

   2. Transformer coupling

   
   
   

   3. Direct coupling

   
   
   

   4. Double-tuned coupling

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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

1. 1. increase

   
   
   

   2. decrease

   
   
   

   3. remain unaffected

   
   
   

   4. drop to zero

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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119. If a two-stage amplifier is required to have an upper cut-off frequency of 2 MHz and a lower cut-off frequency of 30 Hz then upper and lower cut -off frequencies of individual st age are respectively
     

1. 1. 4 MHz, 60 Hz

   
   
   

   2. 3 MHz, 20 Hz

   
   
   

   3. 3 MHz, 60 Hz

   
   
   

   4. 4 MHz, 20 Hz

   
   
   

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1. View Hint View Answer Discuss in Forum

   fL* =	fL
   	√21 / n - 1

   
   and f_H* = f_H √2^{1 / n} - 1
   Putting n = 2, we have
   f_H ≈ 3.1 MHz and f_L ≈ 19.3 MHz ≈ 20 Hz

   Correct Option: B

   fL* =	fL
   	√21 / n - 1

   
   and f_H* = f_H √2^{1 / n} - 1
   Putting n = 2, we have
   f_H ≈ 3.1 MHz and f_L ≈ 19.3 MHz ≈ 20 Hz

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120. A multistage amplifier has a low-pass response with three real poles at s = – ω₁, s = – ω₂ and s = – ω₃. The approximate overall bandwidth B of the amplifier is given by
     

1. 1. B = ω₁ + ω₂ + ω₃

   
   
   

   2. 	1	=	1	+	1	+	1
      	B		ω1		ω2		ω3

   
   
   

   3. B = (ω₁ ω₂ ω₃)^{1 / 3}

   
   
   

   4. B = √(ω₁² + ω₂² + ω₃²
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   Cascading amplifier results in higher low– 3dB frequency and higher 3– dB frequency.
   

   Correct Option: A

   Cascading amplifier results in higher low– 3dB frequency and higher 3– dB frequency.
   

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