Digital Electronics And Logic Design Set 20

Computer Science Engineering (CSE),

Electronics and Telecommunication Engineering [ENTC]

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This set of Digital Electronics and Logic Design Multiple Choice Questions & Answers (MCQs) focuses on Digital Electronics And Logic Design Set 20

Q1 | The dynamic hazard problem occurs in
  • combinational circuit alone
  • sequential circuit only
  • both (a) and (b)
  • none of these
Answer: both (a) and (b)
Q2 | A n-stage ripple counter will count up to
  • 2n
  • 2n-1
  • n
  • 2n-1
Answer: 2n
Q3 | The clock signals are used in sequential logic circuits to
  • tell the time of the day
  • tell how much time has elapsed since the system was turned on
  • carry parllel data signals
  • synchroniz e events in various parts of system
Answer: synchroniz e events in various parts of system
Q4 | 74L5138 chip functions as
  • decoder/demu ltiplexer
  • encoder
  • multiplexer
  • demultiple xer
Answer: decoder/demu ltiplexer
Q5 | A sequential circuit outputs a ONE when an even number (> 0) of one's are input; otherwise the output is ZERO. The minimum number of states required is
  • 0
  • 1
  • 2
  • none of these
Answer: 2
Q6 | A shift register can be used for
  • digital delay line
  • serial to parallel conversion
  • parallel to serial conversion
  • all of these
Answer: all of these
Q7 | Popular application of flip-flop are
  • transfer register
  • shift registers
  • counters
  • all of these
Answer: all of these
Q8 | For which of the following flip-flops, the output is clearly defined for all combinations of two inputs ?
  • q type flip-flop
  • r-s flip-lop
  • j-k flip-lop
  • d flip-flop
Answer: j-k flip-lop
Q9 | When a large number of analog signals are to be converted an analog multiplexer is used. In this case most suitable A.D. converter will be
  • ripple carry counter type
  • dual stop type
  • forward counter type
  • successive approxima tion type
Answer: successive approxima tion type
Q10 | To build a mod-19 counter the number of flip-flops required is
  • 3
  • 5
  • 7
  • 9
Answer: 5
Q11 | The astable multivibrator has
  • two quasi stable states
  • two stable states
  • one stable and one quasi-stable state
  • none of these
Answer: two quasi stable states
Q12 | How many bits are required to encode all twenty six letters, ten symbols, and ten numerals ?
  • 5
  • 6
  • 10
  • 48
Answer: 6
Q13 | The functional difference between S-R flip-flop and J-K flip-flop is that J- K flip-flop
  • is faster than s- r flip-flop
  • has a feed- back path
  • accepts both inputs 1
  • both (a) and (b)
Answer: accepts both inputs 1
Q14 | In a positive edge triggered JK flip-flop, a low J and low K produces
  • no change
  • low state
  • high state
  • none of thes
Answer: no change
Q15 | When an inverter is placed between both inputs of an SR flip-flop, then resulting flip-lop is
  • jk flip-flop
  • d flip-flop
  • sr flip-flop
  • master slave jk flip-flop
Answer: d flip-flop
Q16 | A 2 MHz signal is applied to the input of a J-K lip-lop which is operating in the 'toggle' mode. The frequency of the signal at the output will be
  • 1 mhz
  • 2 mhz
  • 6 mhz
  • 8 mhz
Answer: 8 mhz
Q17 | The master slave JK lip-flop is effectively a combination of
  • a sr flip-flop and a t flip- flop
  • an sr flip- lfop and a d flip-flop
  • a t flip-flop and a d flip- flop
  • two d flip- flops
Answer: a sr flip-flop and a t flip- flop
Q18 | It is difficult to design asynhronous sequential circuit because
  • external clock is to be provided
  • it is more complex
  • both (a) and (b)
  • generally they involve stability problem
Answer: generally they involve stability problem
Q19 | A stable multivibrator is used as
  • comparator circuit
  • demultiplexe r
  • frequency to voltage converter
  • voltage to frequency converter
Answer: comparator circuit
Q20 | How many flip-flop are needed to divide the input frequency by 64 ?
  • 2
  • 5
  • 6
  • 8
Answer: 6
Q21 | 41: In a ripple counter using edge triggered JK flfp-flops, the pulse input is applied to the
  • clock input of all flip-flops
  • clock input of one flip- flops
  • j and k inputs of all flip-flops
  • j and k inputs of one flip- flop
Answer: j and k inputs of all flip-flops
Q22 | The number of clock pulses needed to shift one byte of data from input to the output of a 4-bit shift register is
  • 10
  • 12
  • 16
  • 32
Answer: 16
Q23 | The main difference between JK and RS flip-flop is that
  • jk flip flop needs a clock pulse
  • there is a feedback in jk lip-lop
  • jk flip-flop accepts both inputs as 1
  • jk flip-flop is acronym of junction cathodemultivibra tor
Answer: jk flip-flop accepts both inputs as 1
Q24 | Which of the following unit will choose to transform decimal number to binary code ?
  • encoder
  • decoder
  • multiplexer
  • counter
Answer: encoder
Q25 | The flip-flops which operate in synchronism with external clock pulses are known as
  • synchronous flip-flop
  • asynchronou s flip-flop
  • either of the above
  • none of these
Answer: synchronous flip-flop
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