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ECE :: Digital Electronics

  1. Four MSI TTL 4-bit ripple counters are cascaded to form a 16-bit binary counter. Its propagation delay is about __________ nanoseconds.

  2. A.
    70
    B.
    140
    C.
    210
    D.
    280

  3. The Boolean function A + BC is reduced form of

  4. A.
    AB + BC
    B.
    AB + ABC
    C.
    (A + B) (A + C)
    D.
    (A + C)B

  5. The accuracy of A/D conversion is generally

  6. A.
    B.
    ± LSB
    C.
    D.
    none of the above

  7. To convert JK flip flop to D flip flop

  8. A.
    connect D to both J and K
    B.
    connect D to J directly and D to K through inverter
    C.
    connect D to K directly and D to J through inverter
    D.
    connect D to K and leave J open

  9. Read cycle is always followed by (during instructions execution)

  10. A.
    read cycle
    B.
    write cycle
    C.
    delete signal
    D.
    none of these

  11. If tp is the pulse width, Δt is the propagation delay, T is period of pulse train then the following condition can avoid the race around condition

  12. A.
    tp = Δt = T
    B.
    2tp > Δt > T
    C.
    tp < Δt < T
    D.
    tp < Δt < T

  13. Which of the following pairs of octal and binary numbers are not equal?

  14. A.
    111 110112 = 7678
    B.
    1101101012 = 6658
    C.
    110102 = 38
    D.
    10101.112 = 25.68

  15. With a JK master-slave flip-flop the master is clocked when the clock is __________ , and the slave is triggered when the clock is __________ .

  16. A.
    low, low
    B.
    high, low
    C.
    low, high
    D.
    high, high

  17. The communicating capacitor reduces turn on time because

  18. A.
    it acts as an open circuit
    B.
    it allows maximum base circuit to flow
    C.
    it aids in removing the excess carrier from the base region
    D.
    none of these

  19. The output impedance of a logic pulser is

  20. A.
    low
    B.
    high
    C.
    may be Low or High
    D.
    can't say