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ECE :: Digital Electronics

  1. A 3 bit synchronous counter uses FF with propagation delay time of 20 ns each. The maximum possible time required for change of state will be.

  2. A.
    60 ns
    B.
    40 ns
    C.
    20 ns
    D.
    None

  3. Computer ICs work reliably because

  4. A.
    they are based on two state design
    B.
    these are made from pure silicon
    C.
    these are maintained at two temperatures
    D.
    none of the above

  5. Octal 16 is equal to decimal

  6. A.
    13
    B.
    14
    C.
    15
    D.
    16

  7. The Boolean expression Y = (A + B + AB) C then Y will be equal to

  8. A.
    AC
    B.
    BC
    C.
    C
    D.
    none

  9. In 8085 microprocessor, how many lines are there in address bus?

  10. A.
    6
    B.
    8
    C.
    12
    D.
    16

  11. A TTL circuit with totem pole output has

  12. A.
    high output impedance
    B.
    low output impedance
    C.
    very high output impedance
    D.
    none of the above

  13. The main drawbacks of EEPROM are

  14. A.
    low density
    B.
    high cost
    C.
    both low density and high cost
    D.
    none of the above

  15. How many JK flip-flops are needed to make a 4-bit shift register?

  16. A.
    2
    B.
    4
    C.
    6
    D.
    8

  17. A 10 MHz square wave clocks 5 bit ripple counter. The frequency of the 3rd FF output is

  18. A.
    2 MHz
    B.
    1.25 MHz
    C.
    50 MHz
    D.
    615 kHz

  19. The radix of a hexadecimal system is

  20. A.
    2
    B.
    3
    C.
    8
    D.
    16