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ECE :: Digital Electronics

  1. Assertion (A): Tristate logic is used for bus oriented systems

    Reason (R): The outputs of a tristate logic are 0, 1 and indeterminant.

  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 value of 25 in octal system is

  4. A.
    40
    B.
    20
    C.
    100
    D.
    200

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  5. Assertion (A): ECL gate has very high speed of operation.

    Reason (R): Transistors in ECL do not go into saturation region.

  6. 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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  7. Assertion (A): TTL is a very popular logic in SSI and MSI category.

    Reason (R): In Schottky TTL the power dissipation is less than in ordinary TTL.

  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. FF16 when converted to 8421BCD =

  10. A.
    0000 0101 0101
    B.
    0010 0101 0101
    C.
    1111 0101 0101
    D.
    1000 0101 0101

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  11. ECL has high switching speed because the transistors are

  12. A.
    switching between cutoff and saturation regions
    B.
    switching between cutoff and active regions
    C.
    switching between active and saturation regions
    D.
    none of the above

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  13. Karnaugh map can not be drawn when the number of variables is more than 4

  14. A.
    True
    B.
    False

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  15. A dynamic RAM cell which holds 5 V has to be refreshed every 20 ms so that the stored voltage does not fall by more than 0.5 V. If the cell has a constant discharge current of 0.1 pA, the storage capacitance of cell is

  16. A.
    4 x 10-6 F
    B.
    4 x 10-9 F
    C.
    4 x 10-12 F
    D.
    4 x 10-15 F

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  17. In which counter does the maximum frequency depend on the modulus?

  18. A.
    Synchronous
    B.
    Ripple
    C.
    Both synchronous and ripple
    D.
    Neither synchronous nor ripple

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  19. A current tracer responds to

  20. A.
    steady current only
    B.
    pulsating current only
    C.
    both pulsating and steady current
    D.
    none of the above

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