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  • Question

  • A special transformer used to convert unbalanced signals to balanced signals is the


  • Options
  • A. balun
  • B. autotransformer
  • C. center-tapped transformer
  • D. step-across transformer

  • Correct Answer
  • balun 

    • Transformers problems

    Search Results

    • 1. 

      What is the power dissipated in the primary of the transformer in the given circuit?


    • Options
    • A. 25 mW
    • B. 500 mW
    • C. 12.5 W
    • D. 62.5 W
      • Discuss
    • 2. Mutual induction is dependent on

    • Options
    • A. winding ratios
    • B. output polarities
    • C. dc voltage levels
    • D. current changes
      • Discuss
    • 3. 

      If the load doubled in value in the given circuit, what reflected resistance would the source see?


    • Options
    • A. 80 Ω
    • B. 400 Ω
    • C. 2 kΩ
    • D. 10 kΩ
      • Discuss
    • 4. What is the turns ratio of the transformer needed to match a 1 kΩ source resistance to a 160 Ω load?

    • Options
    • A. 2.5:1
    • B. 0.4:1
    • C. 6.25:1
    • D. 16:1
      • Discuss
    • 5. The coefficient of coupling between two coils is 0.45. The first coil has an inductance of 75 mH and the second coil has an inductance of 105 mH. What is the mutual inductance between the coils?

    • Options
    • A. 3.54 mH
    • B. 7.88 mH
    • C. 39.9 mH
    • D. 189.3 mH
      • Discuss
    • 6. 

      What is the secondary voltage in the given circuit?


    • Options
    • A. 13.3 V rms in phase with the primary
    • B. 120 V rms in phase with the primary
    • C. 13.3 V rms out of phase with the primary
    • D. 120 V rms out of phase with the primary
      • Discuss
    • 7. When does maximum power transfer happen from the source to the load?

    • Options
    • A. When the source resistance is greater than the load resistance
    • B. When the source resistance is less than the load resistance
    • C. When there is negligible source resistance
    • D. When the source resistance equals the load resistance
      • Discuss
    • 8. If the primary power of an ideal transformer having a 2:1 voltage ratio is 100 W, the secondary power is

    • Options
    • A. 100 W
    • B. 50 W
    • C. 75 W
    • D. 200 W
      • Discuss
    • 9. A transformer is plugged into a 120 V rms source and has a primary current of 300 mA rms. The secondary is providing 18 V across a 10 Ω load. What is the efficiency of the transformer?

    • Options
    • A. 88%
    • B. 90%
    • C. 92%
    • D. 95%
      • Discuss
    • 10. The transformer turns ratio determines

    • Options
    • A. the ratio of primary and secondary voltages
    • B. the ratio of primary and secondary currents
    • C. the reflected impedance
    • D. all of the above
      • Discuss

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