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  • Question

  • A step down cycloconverter has an input frequency f. If it uses natural commutation, the output frequency


  • Options
  • A. must be a sub-multiple of input frequency
  • B. can be any frequency
  • C. must be an even sub-multiple of input frequency
  • D. must be an odd sub-multiple of input frequency

  • Correct Answer
  • must be a sub-multiple of input frequency 

    • More questions

    • 1. When temperature is above ferromagnetic Curie temperature, a ferromagnetic material

    • Options
    • A. becomes a paramagnetic material
    • B. becomes a very strong ferromagnetic material
    • C. becomes diamagnetic material
    • D. none of the above
      • Discuss
    • 2. The dipole moment per unit volume P as a function of E for an insulator is

    • Options
    • A. P = ?0 E(?r)
    • B. P = ?0 E
    • C. P = ?0(?r - 1) E
    • D. P =
      • Discuss
    • 3. When a trivalent impurity is added, the semiconductor becomes

    • Options
    • A. p type
    • B. n type
    • C. intrinsic
    • D. neutral
      • Discuss
    • 4. Which of these has the highest dielectric strength?

    • Options
    • A. Mica
    • B. Air
    • C. Cotton
    • D. Rubber
      • Discuss
    • 5. Consider the probability density f(x) = ae-b|x| where x is a random variable whose allowable values range from x = - ? to x = + ?. P(1 ? x ? 2)

    • Options
    • A.
    • B.
    • C.
    • D. (e-b - e-2b)
      • Discuss
    • 6. Which of these devices is used in relaxation oscillator?

    • Options
    • A. UJT
    • B. SCR
    • C. DIAC
    • D. TRIAC
      • Discuss
    • 7. The number of turns in a coil is doubled. If initial time constant is T, the new time constant is

    • Options
    • A. T
    • B. 2T
    • C. 4T
    • D.
      • Discuss
    • 8. A PIN diode can be used

    • Options
    • A. as a shunt mounted switch
    • B. as a series mounted switch
    • C. both as series or shunt mounted switch
    • D. non of the above
      • Discuss
    • 9. Which converter is used in HVDC transmission?

    • Options
    • A. 3 pulse
    • B. 6 pulse
    • C. 12 pulse
    • D. 24 pulse
      • Discuss
    • 10. Two coaxial metallic cylinders have radii R1 and R2. The space between them is filled with a dielectric having dielectric constant ?r. The capacitance per metre length is

    • Options
    • A.
    • B.
    • C.
    • D.
      • Discuss

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