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ECE :: Digital Electronics

  1. Assertion (A): The TTL output acts as a current sink in low state

    Reason (R): The TTL input current is largest in low state.

  2. A.
    Both A and R are correct and R is correct explanation of A
    B.
    Both A and R are correct but R is not correct explanation of A
    C.
    A is true, R is false
    D.
    A is false, R is true

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  3. The number of LED display indicators in logic probe are

  4. A.
    1
    B.
    2
    C.
    1 or 2
    D.
    4

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  5. The time needed by a TTL circuit to switch from 0 to 1 or 1 to 0 is about

  6. A.
    10 μs
    B.
    10 ns
    C.
    100 μs
    D.
    50 ns

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  7. Assertion (A): R-2R ladder type DAC has higher speed of operation than weighted resistor DAC

    Reason (R): R-2R ladder type DAC uses only two different values of resistor network uses many different values of resistors

  8. A.
    Both A and R are correct and R is correct explanation of A
    B.
    Both A and R are correct but R is not correct explanation of A
    C.
    A is true, R is false
    D.
    A is false, R is true

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  9. Which of the following circuits can be used as parallel-to-series converter?

  10. A.
    Digital counter
    B.
    Decoder
    C.
    Demultiplexer
    D.
    Multiplexer

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  11. RAM can be expanded to

  12. A.
    increase word size
    B.
    increase word number
    C.
    either increase word size or increase word number
    D.
    none of the above

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  13. Large scale integration refers to

  14. A.
    more than 50 gates on the same chip
    B.
    more than 80 gates on the same chip
    C.
    more than 100 gates on the same chip
    D.
    none of the above

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  15. Which of the following statements is not true in regard to storage time of a diode?

  16. A.
    During this time, the diode is reverse-biased
    B.
    The diode conducts during this time
    C.
    It is due to the time taken by carriers to depart from the function when the diode is reverse-biased
    D.
    During this time the diode current is zero

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  17. Suppose a microprocessor has memory locations from 0000 to 3FFF, each storing I byte. How many bytes the memory can storing I bytes the memory can store?

  18. A.
    4384
    B.
    8644
    C.
    12688
    D.
    16384

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  19. If the number of information bits is m, the number of parity bits p in the Hamming code is given by equation

  20. A.
    2p = m + p + 1
    B.
    2p ≥ m + p + 1
    C.
    2P = m + p
    D.
    2p ≥ m + p

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