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  • Question

  • The output of a standard TTL NAND gate is used to pull an LED indicator LOW. The LED is in series with a 470-Ω resistor. What is the current in the circuit when the LED is on?


  • Options
  • A. 7.02 mA
  • B. 8.51 mA
  • C. 10.63 mA
  • D. 5.32 mA

  • Correct Answer
  • 7.02 mA 

    • More questions

    • 1. In the digital clock project, the ENT input and RCO output can be used for synchronous counter cascading.

    • Options
    • A. True
    • B. False
      • Discuss
    • 2. A pull-up resistor is a resistor used to keep a given point in a circuit HIGH when in the active state.

    • Options
    • A. True
    • B. False
      • Discuss
    • 3. The 74139 dual four-line demultiplexer functions as a demultiplexer if data input is on the line.

    • Options
    • A. True
    • B. False
      • Discuss
    • 4. When VGS = 0 on an N-channel MOSFET switch, there is no ________ between the source and the drain.

    • Options
    • A. voltage drop
    • B. conductive channel
    • C. capacitance
    • D. inductance
      • Discuss
    • 5. The minimum number of flip-flops that can be used to construct a modulus-5 counter is ________.

    • Options
    • A. 3
    • B. 5
    • C. 8
    • D. 10
      • Discuss
    • 6. The timing network that sets the output frequency of a 555 astable circuit contains ________.

    • Options
    • A. three external resistors are used
    • B. two external resistors and an external capacitor are used
    • C. an external resistor and two external capacitors are used
    • D. no external resistor or capacitor is required
      • Discuss
    • 7. When analog inputs from several sources are to be converted, a multiplexing technique can be used so that one ADC may be time-shared.

    • Options
    • A. True
    • B. False
      • Discuss
    • 8. A parallel in/serial out shift register enters all data bits simultaneously and transfers them out one bit at a time.

    • Options
    • A. True
    • B. False
      • Discuss
    • 9. In VHDL, if we need to remember a value it must be stored in a ________.

    • Options
    • A. function
    • B. type declaration
    • C. variable
    • D. process
      • Discuss
    • 10. The summing outputs of a half- or full-adder are designated by which Greek symbol?

    • Options
    • A. omega
    • B. theta
    • C. lambda
    • D. sigma
      • Discuss

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