Digital Electronics

25 Questions

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Digital Electronics Quizzes & Trivia

This is a MCQ Test for basic Electronics. It is ideal for any technical examination.


Questions and Answers
  • 1. 
    In which of the following base systems is 123 not a valid number?
    • A. 

      Base 10

    • B. 

      Base 16

    • C. 

      Base8

    • D. 

      Base 3

  • 2. 
    Storage of 1 KB means the following number of bytes
    • A. 

      1000

    • B. 

      964

    • C. 

      1024

    • D. 

      1064

  • 3. 
    What is the octal equivalent of the binary number:10111101
    • A. 

      675

    • B. 

      275

    • C. 

      572

    • D. 

      573

  • 4. 
    Pick out the CORRECT statement:
    • A. 

      In a positional number system, each symbol represents the same value irrespective of its position

    • B. 

      The highest symbol in a position number system as a value equal to the number of symbols in the system

    • C. 

      It is not always possible to find the exact binary

    • D. 

      Each hexadecimal digit can be represented as a sequence of three binary symbols.

  • 5. 
    The binary code of (21.125)10 is
    • A. 

      10101.001

    • B. 

      10100.001

    • C. 

      10101.010

    • D. 

      10100.111

  • 6. 
    A NAND gate is called a universal logic element because
    • A. 

      it is used by everybody

    • B. 

      Any logic function can be realized by NAND gates alone

    • C. 

      All the minization techniques are applicable for optimum NAND gate realization

    • D. 

      Many digital computers use NAND gates

  • 7. 
    Digital computers are more widely used as compared to analog computers, because they are
    • A. 

      Less expensive

    • B. 

      Always more accurate and faster

    • C. 

      Useful over wider ranges of problem types

    • D. 

      Easier to maintain

  • 8. 
    Most of the digital computers do not have floating point hardware because
    • A. 

      floating point hardware is costly

    • B. 

      it is slower than software

    • C. 

      It is not possible to perform floating point addition by hardware

    • D. 

      Of no specific reason

  • 9. 
    The number 1000 would appear just immediately after
    • A. 

      FFFF (hex)

    • B. 

      1111 (binary)

    • C. 

      7777 (octal)

    • D. 

      All of the above

  • 10. 
     (10101)2 is
    • A. 

      (37)10

    • B. 

      ( 69)10

    • C. 

      (41 )10

    • D. 

      — (5)10

  • 11. 
    The number of Boolean functions that can be generated by n variables is equal to
    • A. 

      2n

    • B. 

      22 n

    • C. 

      2n-1

    • D. 

      — 2n

  • 12. 
    Consider the representation of six-bit numbers by two’s complement, one’s complement, or by sign and magnitude: In which representation is there overflow from the addition of the integers 011000 and 011000?
    • A. 

      Two’s complement only

    • B. 

      Sign and magnitude and one’s complement only

    • C. 

      Two’s complement and one’s complement only

    • D. 

      All three representations

  • 13. 
    A hexadecimal odometer displays F 52 F. The next reading will be
    • A. 

      F52E

    • B. 

      G52F

    • C. 

      F53F

    • D. 

      F53O

  • 14. 
    Positive logic in a logic circuit is one in which
    • A. 

      Logic 0 and 1 are represented by 0 and positive voltage respectively

    • B. 

      Logic 0 and, -1 are represented by negative and positive voltages respectively

    • C. 

      Logic 0 voltage level is higher than logic 1 voltage level

    • D. 

      logic 0 voltage level is lower than logic 1 voltage level

  • 15. 
     Which of the following gate is a two-level logic gate
    • A. 

      OR gate

    • B. 

      NAND gate

    • C. 

      EXCLUSIVE OR gate

    • D. 

      NOT gate.

  • 16. 
    Among the logic families, the family which can be used at very high frequency greater than 100 MHz in a 4 bitsynchronous counter is
    • A. 

      TTLAS

    • B. 

      CMOS

    • C. 

      ECL

    • D. 

      TTLLS

  • 17. 
    An AND gate will function as OR if
    • A. 

      All the inputs to the gates are “1”

    • B. 

      All the inputs are ‘0’

    • C. 

      Either of the inputs is “1”

    • D. 

      All the inputs and outputs are complemented

  • 18. 
    An OR gate has 6 inputs. The number of input words in its truth table are
    • A. 

      6

    • B. 

      32

    • C. 

      64

    • D. 

      128

  • 19. 
    A debouncing circuit is
    • A. 

      An astable MV

    • B. 

      A bistable MV

    • C. 

      A latch

    • D. 

      A monostable MV.

  • 20. 
    NAND. gates are preferred over others because these
    • A. 

      Have lower fabrication area

    • B. 

      Can be used to make any gate

    • C. 

      Consume least electronic power

    • D. 

      Provide maximum density in a chip

  • 21. 
    In case of OR gate, no matter what the number of inputs, a
    • A. 

      1 at any input causes the output to be at logic 1

    • B. 

      1 at any input causes the output to be at logic 0

    • C. 

      0 any input causes the output to be at logic 0

    • D. 

      0 at any input causes the output to be at logic 1

  • 22. 
    The fan put of a 7400 NAND gate is
    • A. 

      2TTL

    • B. 

      5TTL

    • C. 

      8TTL

    • D. 

      10TTL

  • 23. 
    Excess-3 code is known as
    • A. 

      Weighted code

    • B. 

      Cyclic redundancy code

    • C. 

      Self-complementing code

    • D. 

      Algebraic code

  • 24. 
    Assuming 8 bits for data, 1 bit for parity, I start bit and 2 stop bits, the number of characters that 1200 BPS communication line can transmit is
    • A. 

      10 CPS

    • B. 

      120 CPS

    • C. 

      12CPS

    • D. 

      None of the above

  • 25. 
    Indicate which of the following three binary additions are correct?1.1011 + 1010 = 10101II. 1010 + 1101 = 10111III. 1010 + 1101 = 11111
    • A. 

      I and II

    • B. 

      II and III

    • C. 

      III only

    • D. 

      II and III