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Home ‣ Digital Electronics ‣ Signals and Switches Comments
  • Question

  • An indication of cutoff in an NPN bipolar transistor is that the:


  • Options
  • A. collector current is maximum
  • B. collector-to-emitter voltage equals zero
  • C. base-to-emitter voltage equals 0.7 V
  • D. collector to emitter appears to be open

  • Correct Answer
  • collector to emitter appears to be open 

    • Signals and Switches problems

    Search Results

    • 1. Why is parallel data transmission preferred over serial data transmission for most applications?

    • Options
    • A. It is much slower.
    • B. It is cheaper.
    • C. More people use it.
    • D. It is much faster.
      • Discuss
    • 2. Why is the given circuit called an inverter?


    • Options
    • A. The output is the opposite (inverse) of the input.
    • B. The output is in phase with the input.
    • C. The output is the same as the input.
    • D. There is no output.
      • Discuss
    • 3. If the input voltage on the base of the transistor in the given figure is changed to +10 V, what is the new voltage at the collector Vc?


    • Options
    • A. Not enough information is provided.
    • B. Vc = 10 V
    • C. Vc = 0 V
    • D. Vc = 5 V
      • Discuss
    • 4. Why, in most applications, are transistor switches used in place of relays?

    • Options
    • A. They consume less power.
    • B. They are faster.
    • C. They are quieter and smaller.
    • D. all of the above
      • Discuss
    • 5. What is a disadvantage of CMOS in place of TTL?

    • Options
    • A. It switches slower.
    • B. It uses less power.
    • C. It is smaller.
    • D. cost
      • Discuss
    • 6. Why does the TTL family use a totem-pole circuit on the output?

    • Options
    • A. It provides active pull-up.
    • B. It provides active pull-down.
    • C. It provides active pull-up and active pull-down.
      • Discuss
    • 7. What is used to graphically show the time relationship between two or more digital waveforms?

    • Options
    • A. reference diagram
    • B. timing diagram
    • C. voltage curve
    • D. load line
      • Discuss
    • 8. What is the advantage of using CMOS logic over TTL?

    • Options
    • A. It switches faster.
    • B. It uses less power.
    • C. It is larger.
    • D. cost
      • Discuss
    • 9. What is the frequency of a clock waveform if the period of that waveform is
      1.25 µs?

    • Options
    • A. 8 kHz
    • B. 0.8 kHz
    • C. 0.8 MHz
    • D. 8 MHz
      • Discuss
    • 10. What can a relay provide between the triggering source and the output that semiconductor switching devices cannot?

    • Options
    • A. total isolation
    • B. faster
    • C. higher current rating
    • D. total isolation and higher current rating
      • Discuss

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