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Home ‣ Digital Electronics ‣ Flip-Flops Comments
  • Question

  • As a general rule for stable flip-flop triggering, the clock pulse rise and fall times must be:


  • Options
  • A. very long.
  • B. very short.
  • C. at a maximum value to enable the input control signals to stabilize.
  • D. of no consequence as long as the levels are within the determinate range of value.

  • Correct Answer
  • very short. 

    • Flip-Flops problems

    Search Results

    • 1. A 555 operating as a monostable multivibrator has a C1 = 100 µF. Determine R1 for a pulse width of 500 ms.

    • Options
    • A. 45 Ω
    • B. 455Ω
    • C. 4.5 kΩ
    • D. 455 kΩ
      • Discuss
    • 2. To completely load and then unload an 8-bit register requires how many clock pulses?

    • Options
    • A. 2
    • B. 4
    • C. 8
    • D. 16
      • Discuss
    • 3. The symbols on this flip-flop device indicate ________.


    • Options
    • A. triggering takes place on the negative-going edge of the CLK pulse
    • B. triggering takes place on the positive-going edge of the CLK pulse
    • C. triggering can take place anytime during the HIGH level of the CLK waveform
    • D. triggering can take place anytime during the LOW level of the CLK waveform
      • Discuss
    • 4. Four positive edge-triggered D flip-flops are used to store a 4-bit binary number as shown below. Determine if the circuit is functioning properly, and if not, what might be wrong.


    • Options
    • A. The circuit is functioning properly.
    • B. Q2 is incorrect; the flip-flop is probably bad.
    • C. The input to flip-flop 3 (D2) is probably wrong; check the source of D2.
    • D. A bad connection probably exists between FF-3 and FF-4, causing FF-3 not to reset.
      • Discuss
    • 5. Master-slave J-K flip-flops are called pulse-triggered or level-triggered devices because input data is read during the entire time the clock pulse is at a LOW level.

    • Options
    • A. True
    • B. False
      • Discuss
    • 6. Propagation delay time, tPLH, is measured from the ________.

    • Options
    • A. triggering edge of the clock pulse to the LOW-to-HIGH transition of the output
    • B. triggering edge of the clock pulse to the HIGH-to-LOW transition of the output
    • C. preset input to the LOW-to-HIGH transition of the output
    • D. clear input to the HIGH-to-LOW transition of the output
      • Discuss
    • 7. The output pulse width of a 555 monostable circuit with R1 = 4.7 kΩ and C1 = 47 µF is ________.

    • Options
    • A. 24 s
    • B. 24 ms
    • C. 243 ms
    • D. 243 µs
      • Discuss
    • 8. What does the triangle on the clock input of a J-K flip-flop mean?

    • Options
    • A. level enabled
    • B. edge-triggered
      • Discuss
    • 9. What is another name for a one-shot?

    • Options
    • A. Monostable
    • B. Multivibrator
    • C. Bistable
    • D. Astable
      • Discuss
    • 10. An invalid condition in the operation of an active-HIGH input S-R latch occurs when ________.

    • Options
    • A. HIGHs are applied simultaneously to both inputs S and R
    • B. LOWs are applied simultaneously to both inputs S and R
    • C. a LOW is applied to the S input while a HIGH is applied to the R input
    • D. a HIGH is applied to the S input while a LOW is applied to the R input
      • Discuss

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