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  • Question
  • Which is not a real advantage of HDL?


  • Options
  • A. Using higher levels of abstraction
  • B. Tailoring components to exactly fit the needs of the project
  • C. The use of graphical tools
  • D. Using higher levels of abstraction and tailoring components to exactly fit the needs of the project

  • Correct Answer
  • The use of graphical tools 


  • Flip-Flops problems


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    • 1. A 555 operating as a monostable multivibrator has an R1 of 220 kΩ. Determine C1 for a pulse width of 4 ms.

    • Options
    • A. 0.017 µF
    • B. 17 pF
    • C. 170 pF
    • D. 1,700 µF
    • Discuss
    • 2. For an S-R flip-flop to be set or reset, the respective input must be:

    • Options
    • A. installed with steering diodes
    • B. in parallel with a limiting resistor
    • C. LOW
    • D. HIGH
    • Discuss
    • 3. A positive edge-triggered J-K flip-flop is used to produce a two-phase clock. However, when the circuit is operated it produces erratic results. Close examination with a scope reveals the presence of glitches. What causes the glitches, and how might the problem be corrected?

    • Options
    • A. The PRESET and CLEAR terminals may have been left floating; they should be properly terminated if not being used.
    • B. The problem is caused by a race condition between the J and K inputs; an inverter should be inserted in one of the terminals to correct the problem.
    • C. A race condition exists between the Q and Q outputs to the AND gate; the AND gate should be replaced with a NAND gate.
    • D. A race condition exists between the clock and the outputs of the flip-flop feeding the AND gate; replace the flip-flop with a negative edge-triggered J-K Flip-Flop.
    • Discuss
    • 4. How many flip-flops are required to produce a divide-by-128 device?

    • Options
    • A. 1
    • B. 4
    • C. 6
    • D. 7
    • Discuss
    • 5. Which statement BEST describes the operation of a negative-edge-triggered D flip-flop?

    • Options
    • A. The logic level at the D input is transferred to Q on NGT of CLK.
    • B. The Q output is ALWAYS identical to the CLK input if the D input is HIGH.
    • C. The Q output is ALWAYS identical to the D input when CLK = PGT.
    • D. The Q output is ALWAYS identical to the D input.
    • Discuss
    • 6. A gated S-R latch and its associated waveforms are shown below. What, if anything, is wrong and what could be causing the problem?


    • Options
    • A. The output is always low; the circuit is defective.
    • B. The Q output should be the complement of the output; the S and R terminals are reversed.
    • C. The Q should be following the R input; the R input is defective.
    • D. There is nothing wrong with the circuit.
    • Discuss
    • 7. A 555 operating as a monostable multivibrator has an R1 of 1 MΩ. Determine C1 for a pulse width of 2 s.

    • Options
    • A. 1.8 µF
    • B. 18 F
    • C. 18 pF
    • D. 18 nF
    • Discuss
    • 8. Two J-K flip-flops with their J-K inputs tied HIGH are cascaded to be used as counters. After four input clock pulses, the binary count is ________.

    • Options
    • A. 00
    • B. 11
    • C. 01
    • D. 10
    • Discuss
    • 9. If both inputs of an S-R flip-flop are LOW, what will happen when the clock goes high?

    • Options
    • A. No change will occur in the output.
    • B. An invalid state will exist.
    • C. The output will toggle.
    • D. The output will reset.
    • Discuss
    • 10. Which of the following is not generally associated with flip-flops?

    • Options
    • A. Hold time
    • B. Propagation delay time
    • C. Interval time
    • D. Set up time
    • Discuss


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