26. Device drivers are:
    

1. 1. The inner most part of the operating system
      

   
   
   

   2. Small, special purpose programs
      

   
   
   

   3. Tiny power cords for external storage devices
      

   
   
   

   4. Experts who know how to maximize the performance of devices

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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27. Which of the following is preferred for VHF/UHF applications?
    

1. 1. BJT
      

   
   
   

   2. MOSFET
      

   
   
   

   3. SIT
      

   
   
   

   4. IGBT

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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28. The cyclo converters require Natural or Forced commutation as under—
    

1. 1. Natural communication in both step-up and step down cyclo converters
      

   
   
   

   2. Forced commutation in both step-up and step down cyclo converters
      

   
   
   

   3. Forced commutation in step up cyclo converters
      

   
   
   

   4. Forced commutation in step-down cyclo converters

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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29. In dc choppers, the wave form for—
    

1. 1. I/p voltage is continuous and o/p voltage is discontinuous

   
   
   

   2. I/p voltage is discontinuous and o/p voltage is continuous

   
   
   

   3. I/p voltage as well as output voltage both are continuous

   
   
   

   4. I/p voltage as well as o/p voltage both are discontinuous

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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30. For thyristor, pulse triggering is preferred to d.c. triggering because—
    1. Gate dissipation is low
    2. Pulse system is simpler
    3. Trigging signal is required for a very short duration
    

1. 1. Only statement 1 is correct
      

   
   
   

   2. Only statement 2 is correct
      

   
   
   

   3. Statements 2 and 3 are correct
      

   
   
   

   4. Statements 1, 2 and 3 are correct

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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