About Digital Electronics

Following are some of the multiple choice questions on the Digital Electronics with answers that will help the students in developing their knowledge.

Digital Electronics MCQ

1. Convert the following decimal number to 8-bit binary.

  • 101110112
  • 110111012
  • 101111012
  • 101111002

2. In the boolean algebra, a variable has ________ different state(s)/value(s).

  • 3
  • 1
  • 2
  • 4

3. An AND gate will function as OR if

  • All the inputs to the gates are “1”
  • All the inputs are ‘0’
  • Either of the inputs is “1”
  • All the inputs and outputs are complemente'

4. Which of the following is Universal Gate?

  • OR gate
  • NAND gate
  • AND gate
  • NOR gate

5. In Boolean algebra, the bar sign (-) indicates ___________.

  • OR operation
  • AND operation
  • NOT operation
  • None of the above

6. Among the logic families, the family which can be used at very high frequency greater than 100 MHz in a 4 bit synchronous counter is

  • TTLAS
  • CMOS
  • ECL
  • TTLLS

7. The inputs of a NAND gate are connected together. The resulting circuit is ___________.

  • OR gate
  • AND gate
  • NOT gate
  • None of the above

8. A NAND gate is called a universal logic element because

  • It is used by everybody
  • Any logic function can be realized by NAND gates alone
  • All the minization techniques are applicable for optimum NAND gate realization
  • Many digital computers use NAND gates.

9. The only function of NOT gate is to ___________.

  • Stop signal
  • Invert input signal
  • Act as a universal gate
  • None of the above

10. Most of the digital computers do not have floating point hardware because

  • Floating point hardware is costly
  • It is slower than software
  • It is not possible to perform floating point addition by hardware
  • Of no specific reason

11. Which type of CPLD packaging can provide maximum number of pins on the package due to small size of the pins?

  • PLCC
  • QFP
  • PGA
  • BGA

12. Which is the example of digital device from the given option ?

  • Record players
  • Microprocessors
  • Sensors
  • Thermistors

13. The full form of CML is                      

  • complementary mode logic
  • current mode logic
  • collector mode logic
  • collector mixed logic

14. The maximum noise voltage that may appear at the input of a logic gate without changing the logical state of its output is termed as                      

  • noise margin
  • noise immunity
  • white noise
  • signal to noise ratio

15. Fan-in is defined as                      

  • the number of outputs connected to gate without any degradation in the voltage levels
  • the number of inputs connected to gate without any degradation in the voltage levels
  • the number of outputs connected to gate with degradation in the voltage levels
  • the number of inputs connected to gate with degradation in the voltage levels

16. Fan-in is defined as                      

  • the number of outputs connected to gate without any degradation in the voltage levels
  • the number of inputs connected to gate without any degradation in the voltage levels
  • the number of outputs connected to gate with degradation in the voltage levels
  • the number of inputs connected to gate with degradation in the voltage levels

17. Power Dissipation in DIC is expressed in

  • watts or kilowatts
  • milliwatts or nanowatts
  • db
  • mdb

18. Power Dissipation in DIC is expressed in

  • watts or kilowatts
  • milliwatts or nanowatts
  • db
  • mdb

19. Propagation delay times can be divided as

  • t(plh) and t(lph)
  • t(lph) and t(phl)
  • t(plh) and t(phl)
  • t(hpl) and t(lph)

20. Propagation delay is defined as

  • the time taken for the output of a gate to change after the inputs have changed
  • the time taken for the input of a gate to change after the outputs have changed
  • the time taken for the input of a gate to change after the intermediates have changed
  • the time taken for the output of a gate to change after the intermediates have changed

21. CMOS refers to                      

  • continuous metal oxide semiconductor
  • complementary metal oxide semiconductor
  • centred metal oxide semiconductor
  • concrete metal oxide semiconductor

22. Applications of PLAs are                            

  • registered pals
  • configurable pals
  • pal programming
  • all of the mentioned

23. In FPGA, vertical and horizontal directions are separated by                          

  • a line
  • a channel
  • a strobe
  • a flip-flop

24. The full form of VLSI is                          

  • very long single integration
  • very least scale integration
  • very large scale integration
  • very long scale integration

25. The FPGA refers to                          

  • first programmable gate array
  • field programmable gate array
  • first program gate array
  • field program gate array

26. If a PAL has been programmed once

  • its logic capacity is lost
  • its outputs are only active high
  • its outputs are only active low
  • it cannot be reprogrammed

27. The difference between a PAL & a PLA is

  • pals and plas are the same thing
  • the pla has a programmable or plane and a programmable and plane, while the pal only has a programmable and plane
  • the pal has a programmable or plane and a programmable and plane, while the pla only has a programmable and plane
  • the pal has more possible product terms than the pla

28. Which type of device FPGA are?

  • sld
  • srom
  • eprom
  • pld

29. The complex programmable logic device contains several PLD blocks and                      

  • a language compiler
  • and/or arrays
  • global interconnection matrix
  • field-programmable switches

30. For programmable logic functions, which type of PLD should be used?

  • pla
  • pal
  • cpld
  • sld

31. Which one of the following is volatile in nature?

  • rom
  • erom
  • prom
  • ram

32. Static RAM employs                      

  • bjt or mosfet
  • fet or jfet
  • capacitor or bjt
  • bjt or mos

33. Dynamic RAM employs                      

  • capacitor or mosfet
  • fet or jfet
  • capacitor or bjt
  • bjt or mos

34. The magnetic core memories have been replaced by semiconductor RAMs, why?

  • semiconductor rams are highly flexible
  • semiconductor rams have highest storing capacity
  • semiconductor rams are smaller in size
  • all of the mentioned

35. The data written in flip-flop remains stored as long as                      

  • power is supplied
  • power is removed
  • power is supplied
  • power is removed

36. What is memory decoding?

  • the process of memory ic used in a digital system is overloaded with data
  • the process of memory ic used in a digital system is selected for the range of address assigned
  • the process of memory ic used in a digital system is selected for the range of data assigned
  • the process of memory ic used in a digital system is overloaded with data allocated in memory cell

37. How many address bits are required to select memory location in Memory decoder?

  • 4 kb
  • 8 kb
  • 12 kb
  • 16 kb

38. The first step in the design of memory decoder is                      

  • selection of a eprom
  • selection of a ram
  • address assignment
  • data insertion

39. PLA is used to implement                          

  • a complex sequential circuit
  • a simple sequential circuit
  • a complex combinational circuit
  • a simple combinational circuit

40. PLA contains                          

  • and and or arrays
  • nand and or arrays
  • not and and arrays
  • nor and or arrays

41. Outputs of the AND gate in PLD is known as                          

  • input lines
  • output lines
  • strobe lines
  • control lines

42. PAL refers to                          

  • programmable array loaded
  • programmable logic array
  • programmable array logic
  • programmable and logic

43. How many types of PLD is?

  • 2
  • 3
  • 4
  • 5

44. Logic circuits can also be designed using

  • ram
  • rom
  • pld
  • pla

45. PLD contains a large number of

  • flip-flops
  • gates
  • registers
  • all of the mentioned

46. A PLA is similar to a ROM in concept except that                          

  • it hasn’t capability to read only
  • it hasn’t capability to read or write operation
  • it doesn’t provide full decoding to the variables
  • it hasn’t capability to write only

47. IC 4116 is organised as                    

  • 512 * 4
  • 16 * 1
  • 32 * 4
  • 64 * 2

48. How memory expansion is done?

  • by increasing the supply voltage of the memory ics
  • by decreasing the supply voltage of the memory ics
  • by connecting memory ics together
  • by separating memory ics

49. How many 16K * 4 RAMs are required to achieve a memory with a capacity of 64K and a word length of 8 bits?

  • 2
  • 4
  • 6
  • 8

50. How many 1024 * 1 RAM chips are required to construct a 1024 * 8 memory system?

  • 4
  • 6
  • 8
  • 12

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