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  • Question

  • A 555 timer is connected for astable operation as shown below along with the output waveform. It is determined that the duty cycle should be 0.5. What steps need to be taken to correct the duty cycle, while maintaining the same output frequency?

    A 555 timer is connected for astable operation as shown below along with the output waveform. It is


  • Options
  • A. Increase the value of C.
  • B. Increase Vcc and decrease RL.
  • C. Decrease R1 and R2.
  • D. Decrease R1 and increase R2.

  • Correct Answer
  • Decrease R1 and increase R2. 

    • More questions

    • 1. The first microprocessor had a(n)________.

    • Options
    • A. 1-bit data bus
    • B. 2-bit data bus
    • C. 4-bit data bus
    • D. 8-bit data bus
      • Discuss
    • 2. If a 3-input OR gate has eight input possibilities, how many of those possibilities will result in a HIGH output?

    • Options
    • A. 1
    • B. 2
    • C. 7
    • D. 8
      • Discuss
    • 3. The select inputs to a multiplexer may also be called address lines.

    • Options
    • A. True
    • B. False
      • Discuss
    • 4. How many 2-input NOR gates does it take to produce a 2-input NAND gate?

    • Options
    • A. 1
    • B. 2
    • C. 3
    • D. 4
      • Discuss
    • 5. The 7476 and 74LS76 are both dual flip-flops.

    • Options
    • A. True
    • B. False
      • Discuss
    • 6. How many different states does a 3-bit asynchronous counter have?

    • Options
    • A. 2
    • B. 4
    • C. 8
    • D. 16
      • Discuss
    • 7. The invalid range for an input to TTL logic is from ________.

    • Options
    • A. 0 to 0.8 V
    • B. 1.2 to 1.6 V
    • C. 0.8 to 2.0 V
    • D. 2.0 to 5.0 V
      • Discuss
    • 8. A typical fan-out for most TTL is 9.

    • Options
    • A. True
    • B. False
      • Discuss
    • 9. The outputs of the 74138 octal decoder are enabled when the enable inputs are
      .

    • Options
    • A. True
    • B. False
      • Discuss
    • 10. Convert the following hexadecimal number to decimal.
      B516

    • Options
    • A. 212
    • B. 197
    • C. 165
    • D. 181
      • Discuss

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