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Home Digital Electronics MSI Logic Circuits See What Others Are Saying!
  • Question
  • A breadboard-circuit design using a BCD-to-decimal decoder has a problem wherein the operation of the system is erratic. The technician uses his scope to examine the waveforms throughout the system and doesn't really see any problems. While he's scratching his head, what helpful advice can you offer him as to what might be wrong and what to do to correct the problem?


  • Options
  • A. The decoder is thermally intermittent; replace it.
  • B. There is probably a bad connection on the wire wrap protoboard; recheck the wiring.
  • C. Glitches are probably the culprit; strobe the decoder.
  • D. The decoder is thermally intermittent and must be replaced; or there is probably a bad connection on the wire wrap protoboard, and the wiring must be rechecked.

  • Correct Answer
  • Glitches are probably the culprit; strobe the decoder. 


  • More questions

    • 1. How is a J-K flip-flop made to toggle?

    • Options
    • A. J = 0, K = 0
    • B. J = 1, K = 0
    • C. J = 0, K = 1
    • D. J = 1, K = 1
    • Discuss
    • 2. The following combination is correct for an ODD parity data transmission system:
      data = 011011100 and parity = 0

    • Options
    • A. True
    • B. False
    • Discuss
    • 3. A major disadvantage of the mask ROM is that it:

    • Options
    • A. is time consuming to change the stored data when system requirements change
    • B. is very expensive to change the stored data when system requirements change
    • C. cannot be reprogrammed if stored data needs to be changed
    • D. has an extremely short life expectancy and requires frequent replacement
    • Discuss
    • 4. One disadvantage of the tracking A/D converter is:

    • Options
    • A. that it requires two counters?one for up and one for down.
    • B. that the binary output will oscillate between two binary states when the analog input is constant.
    • C. the need for an accurate clock reference for the counter.
    • D. the need for a latch and its associated control circuit.
    • Discuss
    • 5. Hexadecimal 44 is ________ in decimal.

    • Options
    • A. 6810
    • B. 7410
    • C. 7710
    • D. 9810
    • Discuss
    • 6. The CPU contains all the circuitry for ________.

    • Options
    • A. storing data
    • B. keeping track of time
    • C. fetching and interpreting instructions
    • D. Internet operations
    • Discuss
    • 7. The Q output of a flip-flop is normally HIGH when the device is in the "CLEAR" or "RESET" state.

    • Options
    • A. True
    • B. False
    • Discuss
    • 8. What must be done to interface TTL to CMOS?

    • Options
    • A. A dropping resistor must be used on the CMOS 12 V supply to reduce it to 5 V for the TTL.
    • B. As long as the CMOS supply voltage is 5 V, they can be interfaced; however, the fan-out of the TTL is limited to five CMOS gates.
    • C. A 5 V Zener diode must be placed across the inputs of the TTL gates in order to protect them from the higher output voltages of the CMOS gates.
    • D. A pull-up resistor must be used between the TTL output-CMOS input node and Vcc; the value of RP will depend on the number of CMOS gates connected to the node.
    • Discuss
    • 9. The input levels to a flip-flop must be maintained for a minimum time period both before and after the edge of the clock signal is applied.

    • Options
    • A. True
    • B. False
    • Discuss
    • 10. A Celsius thermometer is an application for the 8051 microcontroller.

    • Options
    • A. True
    • B. False
    • Discuss


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