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Home ‣ Digital Electronics ‣ Multivibrators and 555 Timer Comments
  • Question

  • What is the output pulse width of the waveform at the output of the circuit in the given figure?

    What is the output pulse width of the waveform at the output of the circuit in the given figure? 1.6


  • Options
  • A. 1.65 ms
  • B. 18.2 ms
  • C. 4.98 ms
  • D. 54.6 ms

  • Correct Answer
  • 18.2 ms 

    • Multivibrators and 555 Timer problems

    Search Results

    • 1. An astable 555 timer has the following number of stable states:

    • Options
    • A. 0
    • B. 1
    • C. 2
    • D. 3
      • Discuss
    • 2. Determine tHI and tLO for the circuit given below.


    • Options
    • A. tHI = 7.95 µs, tLO = 6.24 µs
    • B. tHI = 6.24 µs, tLO = 7.95 µs
    • C. tHI = 3.97 µs, tLO = 3.21 µs
    • D. tHI = 3.21 µs, tLO = 3.97 µs
      • Discuss
    • 3. Is there any limit to the number of times that a 74123 can be retriggered?

    • Options
    • A. yes
    • B. no
      • Discuss
    • 4. A crystal demonstrates the ________ effect when a mechanical force across the crystal causes a small voltage to be generated.

    • Options
    • A. photoelectric
    • B. Co-pitts
    • C. piezoelectric
    • D. flywheel
      • Discuss
    • 5. An astable multivibrator requires:

    • Options
    • A. balanced time constants
    • B. a pair of matched transistors
    • C. no input signal
    • D. dual J-K flip-flops
      • Discuss
    • 6. What is the difference between an astable multivibrator and a monostable multivibrator?

    • Options
    • A. The astable is free running.
    • B. The astable needs to be clocked.
    • C. The monostable is free running.
    • D. none of the above
      • Discuss
    • 7. A retriggerable one shot has a pulse of 10 ms. 3 ms after being triggered, another trigger pulse is applied. The resulting output pulse will be ________ ms.

    • Options
    • A. 3
    • B. 7
    • C. 10
    • D. 13
      • Discuss
    • 8. Which mode of operation is being used when a 555 timer chip has two external resistors and an external capacitor?

    • Options
    • A. monostable
    • B. pulse stretching
    • C. Schmitt triggering
    • D. astable
      • Discuss
    • 9. If the resistor in the Schmitt trigger astable multivibrator is a variable resistor, what part of the output voltage waveform will change when the resistance is changed?

    • Options
    • A. the shape of the waveform
    • B. the amplitude of the waveform
    • C. the period of the waveform
    • D. none of the above
      • Discuss
    • 10. The ________ is defined as the time the output is active divided by the total period of the output signal.

    • Options
    • A. on time
    • B. off time
    • C. duty cycle
    • D. active ratio
      • Discuss

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