340+ Digital Logic Circuits (DLC) Solved MCQs

201.

Complement of F’ gives back  

A. f’
B. f
C. ff
D. ff’
Answer» B. f
202.

Decimal digit in BCD can be represented by                          

A. 1 input line
B. 2 input lines
C. 3 input lines
D. 4 input lines
Answer» D. 4 input lines
203.

The number of logic gates and the way of their interconnections can be classified as

A. logical network
B. system network
C. circuit network
D. gate network
Answer» A. logical network
204.

EPROM uses an array of                                

A. p-channel enhancement type mosfet
B. n-channel enhancement type mosfet
C. p-channel depletion type mosfet
D. n-channel depletion type mosfet
Answer» B. n-channel enhancement type mosfet
205.

The EPROM was invented by                              

A. wen tsing chow
B. dov frohman
C. luis o brian
D. j p longwell
Answer» B. dov frohman
206.

Address decoding for dynamic memory chip control may also be used for

A. chip selection and address location
B. read and write control
C. controlling refresh circuits
D. memory mapping
Answer» A. chip selection and address location
207.

Which of the following describes the action of storing a bit of data in a mask ROM?

A. a 0 is stored by connecting the gate of a mos cell to the address line
B. a 0 is stored in a bipolar cell by shorting the base connection to the address line
C. a 1 is stored by connecting the gate of a mos cell to the address line
D. a 1 is stored in a bipolar cell by opening the base connection to the address line
Answer» C. a 1 is stored by connecting the gate of a mos cell to the address line
208.

The check sum method of testing a ROM                              

A. allows data errors to be pinpointed to a specific memory location
B. provides a means for locating and correcting data errors in specific memory locations
C. indicates if the data in more than one memory location is incorrect
D. simply indicates that the contents of the rom are incorrect
Answer» D. simply indicates that the contents of the rom are incorrect
209.

The initial values in all the cells of an EPROM is                              

A. 0
B. 1
C. both 0 and 1
D. alternate 0s and 1s
Answer» B. 1
210.

To store 0 in such a cell, the floating point must be                              

A. reprogrammed
B. restarted
C. charged
D. power off
Answer» C. charged
211.

The major disadvantage of RAM is?

A. its access speed is too slow
B. its matrix size is too big
C. it is volatile
D. high power consumption
Answer» C. it is volatile
212.

Which one of the following is used for the fabrication of MOS EPROM?

A. tms 2513
B. tms 2515
C. tms 2516
D. tms 2518
Answer» C. tms 2516
213.

How many addresses a MOS EPROM have?

A. 1024
B. 512
C. 2516
D. 256
Answer» C. 2516
214.

ROMs retain data when                              

A. power is on
B. power is off
C. system is down
D. all of the mentioned
Answer» D. all of the mentioned
215.

When a RAM module passes the checker board test it is                              

A. able to read and write only 0s
B. faulty
C. probably good
D. able to read and write only 1s
Answer» C. probably good
216.

What is the difference between static RAM and dynamic RAM?

A. static ram must be refreshed, dynamic ram does not
B. there is no difference
C. dynamic ram must be refreshed, static ram does not
D. sram is slower than dram
Answer» C. dynamic ram must be refreshed, static ram does not
217.

How many natural states will there be in a 4-bit ripple counter?

A. 4
B. 8
C. 16
D. 32
Answer» C. 16
218.

A ripple counter’s speed is limited by the propagation delay of  

A. each flip-flop
B. all flip-flops and gates
C. the flip-flops only with gates
D. only circuit gates
Answer» A. each flip-flop
219.

One of the major drawbacks to the use of asynchronous counters is that                          

A. low-frequency applications are limited because of internal propagation delays
B. high-frequency applications are limited because of internal propagation delays
C. asynchronous counters do not have major drawbacks and are suitable for use in high- and low-frequency counting applications
D. asynchronous counters do not have propagation delays, which limits their use in high- frequency applications
Answer» B. high-frequency applications are limited because of internal propagation delays
220.

Internal propagation delay of asynchronous counter is removed by                          

A. ripple counter
B. ring counter
C. modulus counter
D. synchronous counter
Answer» D. synchronous counter
221.

How many flip-flops are required to construct a decade counter?

A. 4
B. 8
C. 5
D. 10
Answer» A. 4
222.

The terminal count of a typical modulus-10 binary counter is                          

A. 0000
B. 1010
C. 1001
D. 1111
Answer» C. 1001
223.

A ripple counter’s speed is limited by the propagation delay of                          

A. each flip-flop
B. all flip-flops and gates
C. the flip-flops only with gates
D. only circuit gates
Answer» A. each flip-flop
224.

A 4-bit counter has a maximum modulus of                          

A. 3
B. 6
C. 8
D. 16
Answer» D. 16
225.

UP-DOWN counter is a combination of                          

A. latches
B. flip-flops
C. up counter
D. up counter & down counter
Answer» D. up counter & down counter
226.

UP-DOWN counter is also known as                        

A. dual counter
B. multi counter
C. multimode counter
D. two counter
Answer» C. multimode counter
227.

In an UP-counter, each flip-flop is triggered by                        

A. the output of the next flip-flop
B. the normal output of the preceding flip-flop
C. the clock pulse of the previous flip-flop
D. the inverted output of the preceding flip-flop
Answer» B. the normal output of the preceding flip-flop
228.

In DOWN-counter, each flip-flop is triggered by                        

A. the output of the next flip-flop
B. the normal output of the preceding flip-flop
C. the clock pulse of the previous flip-flop
D. the inverted output of the preceding flip-flop
Answer» D. the inverted output of the preceding flip-flop
229.

Binary counter that count incrementally and decrement is called                        

A. up-down counter
B. lsi counters
C. down counter
D. up counter
Answer» A. up-down counter
230.

Once an up-/down-counter begins its count sequence, it                        

A. starts counting
B. can be reversed
C. can’t be reversed
D. can be altered
Answer» D. can be altered
231.

In 4-bit up-down counter, how many flip-flops are required?

A. 2
B. 3
C. 4
D. 5
Answer» C. 4
232.

A modulus-10 counter must have _

A. 10 flip-flops
B. 4 flip-flops
C. 2 flip-flops
D. synchronous clocking
Answer» B. 4 flip-flops
233.

Which is not an example of a truncated modulus?

A. 8
B. 9
C. 11
D. 15
Answer» A. 8
234.

The designation means that the                  

A. up count is active-high, the down count is active-low
B. up count is active-low, the down count is active-high
C. up and down counts are both active-low
D. up and down counts are both active-high
Answer» A. up count is active-high, the down count is active-low
235.

The full form of SIPO is                        

A. serial-in parallel-out
B. parallel-in serial-out
C. serial-in serial-out
D. serial-in peripheral-out
Answer» A. serial-in parallel-out
236.

How can parallel data be taken out of a shift register simultaneously?

A. use the q output of the first ff
B. use the q output of the last ff
C. tie all of the q outputs together
D. use the q output of each ff
Answer» D. use the q output of each ff
237.

What is meant by parallel load of a shift register?

A. all ffs are preset with data
B. each ff is loaded with data, one at a time
C. parallel shifting of data
D. all ffs are set with data
Answer» A. all ffs are preset with data
238.

After three clock pulses, the register contains                  

A. 01110
B. 00001
C. 00101
D. 00110
Answer» C. 00101
239.

What will be the 4-bit pattern after the second clock pulse? (Right-most bit first)

A. 1100
B. 0011
C. 0000
D. 1111
Answer» C. 0000
240.

In digital logic, a counter is a device which                          

A. counts the number of outputs
B. stores the number of times a particular event or process has occurred
C. stores the number of times a clock pulse rises and falls
D. counts the number of inputs
Answer» B. stores the number of times a particular event or process has occurred
241.

A counter circuit is usually constructed of                          

A. a number of latches connected in cascade form
B. a number of nand gates connected in cascade form
C. a number of flip-flops connected in cascade
D. a number of nor gates connected in cascade form
Answer» C. a number of flip-flops connected in cascade
242.

How many types of the counter are there?

A. 2
B. 3
C. 4
D. 5
Answer» B. 3
243.

A decimal counter has states.

A. 5
B. 10
C. 15
D. 20
Answer» B. 10
244.

Ripple counters are also called                          

A. ssi counters
B. asynchronous counters
C. synchronous counters
D. vlsi counters
Answer» B. asynchronous counters
245.

Synchronous counter is a type of                          

A. ssi counters
B. lsi counters
C. msi counters
D. vlsi counters
Answer» C. msi counters
246.

Three decade counter would have                          

A. 2 bcd counters
B. 3 bcd counters
C. 4 bcd counters
D. 5 bcd counters
Answer» B. 3 bcd counters
247.

BCD counter is also known as                          

A. parallel counter
B. decade counter
C. synchronous counter
D. vlsi counter
Answer» B. decade counter
248.

The parallel outputs of a counter circuit represent the                            

A. parallel data word
B. clock frequency
C. counter modulus
D. clock count
Answer» D. clock count
249.

The time from the beginning of a read cycle to the end of tACS/tAA is called as

A. write enable time
B. data hold
C. read cycle time
D. access time
Answer» D. access time
250.

Why did PROM introduced?

A. to increase the storage capacity
B. to increase the address locations
C. to provide flexibility
D. to reduce the size
Answer» C. to provide flexibility
251.

Which of the following is programmed electrically by the user?

A. rom
B. eprom
C. prom
D. eeprom
Answer» C. prom
252.

PROMs are available in                        

A. bipolar and mosfet technologies
B. mosfet and fet technologies
C. fet and bipolar technologies
D. mos and bipolar technologies
Answer» D. mos and bipolar technologies
253.

Which of the following best describes the fusible-link PROM?

A. manufacturer-programmable, reprogrammable
B. manufacturer-programmable, one-time programmable
C. user-programmable, reprogrammable
D. user-programmable, one-time programmable
Answer» D. user-programmable, one-time programmable
254.

How can ultraviolet erasable PROMs be recognized?

A. there is a small window on the chip
B. they will have a small violet dot next to the #1 pin
C. their part number always starts with a “u”, such as in u12
D. they are not readily identifiable, since they must always be kept under a small cover
Answer» A. there is a small window on the chip
255.

Which part of a Flash memory architecture manages all chip functions?

A. program verify code
B. floating-gate mosfet
C. command code
D. input/output pins
Answer» B. floating-gate mosfet
256.

How much locations an 8-bit address code can select in memory?

A. 8 locations
B. 256 locations
C. 65,536 locations
D. 131,072 locations
Answer» B. 256 locations
257.

What is a fusing process?

A. it is a process by which data is passed to the memory
B. it is a process by which data is read through the memory
C. it is a process by which programs are burnout to the diode/transistors
D. it is a process by which data is fetched through the memory
Answer» C. it is a process by which programs are burnout to the diode/transistors
258.

Fusing process is                        

A. reversible
B. irreversible
C. synchronous
D. asynchronous
Answer» B. irreversible
259.

The cell type used inside a PROM is                        

A. link cells
B. metal cells
C. fuse cells
D. electric cells
Answer» C. fuse cells
260.

How many types of fuse technologies are used in PROMs?

A. 2
B. 3
C. 4
D. 5
Answer» B. 3
261.

Metal links are made up of                        

A. polycrystalline
B. magnesium sulphide
C. nichrome
D. silicon dioxide
Answer» C. nichrome
262.

Silicon links are made up of                            

A. polycrystalline silicon
B. polycrystalline magnesium
C. nichrome
D. silicon dioxide
Answer» A. polycrystalline silicon
263.

During programming p-n junction is                            

A. avalanche reverse biased
B. avalanche forward biased
C. zener reverse biased
D. zener reverse biased
Answer» A. avalanche reverse biased
264.

The full form of FAMOS is                            

A. floating gate avalanche injection mos
B. float gate avalanche injection mos
C. floating gate avalanche induction mos
D. float gate avalanche induction mos
Answer» A. floating gate avalanche injection mos
265.

PROM is programmed by                            

A. eprom programmer
B. eeprom programmer
C. prom programmer
D. rom programmer
Answer» C. prom programmer
266.

The PROM starts out with                            

A. 1s
B. 0s
C. null
D. both 1s and 0s
Answer» B. 0s
267.

For implementation of PROM, which IC is used?

A. ic 74187
B. ic 74186
C. ic 74185
D. ic 74184
Answer» B. ic 74186
268.

IC 74186 is of                              

A. 1024 bits
B. 32 bits
C. 512 bits
D. 64 bits
Answer» C. 512 bits
269.

How many memory locations are addressed using 18 address bits?

A. 165,667
B. 245,784
C. 262,144
D. 212,342
Answer» C. 262,144
270.

How many address bits are needed to operate a 2K * 8-bit memory?

A. 10
B. 11
C. 12
D. 13
Answer» B. 11
271.

What is the bit storage capacity of a ROM with a 1024 × 8 organization?

A. 1024
B. 4096
C. 2048
D. 8192
Answer» D. 8192
272.

The logical sum of two or more logical product terms is called                      

A. sop
B. pos
C. or operation
D. nand operation
Answer» A. sop
273.

The expression Y=AB+BC+AC shows the operation.

A. ex-or
B. sop
C. pos
D. nor
Answer» B. sop
274.

The expression Y=(A+B)(B+C)(C+A) shows the operation.

A. and
B. pos
C. sop
D. nand
Answer» B. pos
275.

The canonical sum of product form of the function y(A,B) = A + B is                      

A. ab + bb + a’a
B. ab + ab’ + a’b
C. ba + ba’ + a’b’
D. ab’ + a’b + a’b’
Answer» B. ab + ab’ + a’b
276.

A variable on its own or in its complemented form is known as a                      

A. product term
B. literal
C. sum term
D. word
Answer» B. literal
277.

Canonical form is a unique way of representing                          

A. sop
B. minterm
C. boolean expressions
D. pos
Answer» C. boolean expressions
278.

There are Minterms for 3 variables (a, b, c).

A. 0
B. 2
C. 8
D. 1
Answer» C. 8
279.

Why is a demultiplexer called a data distributor?

A. the input will be distributed to one of the outputs
B. one of the inputs will be selected for the output
C. the output will be distributed to one of the inputs
D. single input gives single output
Answer» A. the input will be distributed to one of the outputs
280.

Most demultiplexers facilitate which type of conversion?

A. decimal-to-hexadecimal
B. single input, multiple outputs
C. ac to dc
D. odd parity to even parity
Answer» B. single input, multiple outputs
281.

In 1-to-4 demultiplexer, how many select lines are required?

A. 2
B. 3
C. 4
D. 5
Answer» A. 2
282.

In a multiplexer the output depends on its                          

A. data inputs
B. select inputs
C. select outputs
D. enable pin
Answer» B. select inputs
283.

In 1-to-4 multiplexer, if C1 = 1 & C2 = 1, then the output will be                          

A. y0
B. y1
C. y2
D. y3
Answer» D. y3
284.

How many select lines are required for a 1-to-8 demultiplexer?

A. 2
B. 3
C. 4
D. 5
Answer» B. 3
285.

How many AND gates are required for a 1-to-8 multiplexer?

A. 2
B. 6
C. 8
D. 5
Answer» C. 8
286.

Which IC is used for the implementation of 1-to-16 DEMUX?

A. ic 74154
B. ic 74155
C. ic 74139
D. ic 74138
Answer» A. ic 74154
287.

The word demultiplex means                        

A. one into many
B. many into one
C. distributor
D. one into many as well as distributor
Answer» D. one into many as well as distributor
288.

Why is a demultiplexer called a data distributor?

A. the input will be distributed to one of the outputs
B. one of the inputs will be selected for the output
C. the output will be distributed to one of the inputs
D. single input to single output
Answer» A. the input will be distributed to one of the outputs
289.

In a multiplexer the output depends on its                        

A. data inputs
B. select inputs
C. select outputs
D. enable pin
Answer» B. select inputs
290.

In 1-to-4 multiplexer, if C1 = 0 & C2 = 1, then the output will be                        

A. y0
B. y1
C. y2
D. y3
Answer» B. y1
291.

In 1-to-4 multiplexer, if C1 = 1 & C2 = 1, then the output will be                        

A. y0
B. y1
C. y2
D. y3
Answer» D. y3
292.

What is the addition of the binary numbers 11011011010 and 010100101?

A. 0111001000
B. 1100110110
C. 11101111111
D. 10011010011
Answer» C. 11101111111
293.

Perform binary addition: 101101 + 011011 = ?

A. 011010
B. 1010100
C. 101110
D. 1001000
Answer» D. 1001000
294.

Binary subtraction of 100101 – 011110 is

A. 000111
B. 111000
C. 010101
D. 101010
Answer» A. 000111
295.

Perform multiplication of the binary numbers: 01001 × 01011 = ?

A. 001100011
B. 110011100
C. 010100110
D. 101010111
Answer» A. 001100011
296.

100101 × 0110 = ?

A. 1011001111
B. 0100110011
C. 101111110
D. 0110100101
Answer» C. 101111110
297.

On multiplication of (10.10) and (01.01), we get

A. 101.0010
B. 0010.101
C. 011.0010
D. 110.0011
Answer» C. 011.0010
298.

Divide the binary numbers: 111101 ÷ 1001 and find the remainder

A. 0010
B. 1010
C. 1100
D. 0011
Answer» D. 0011
299.

Divide the binary number (011010000) by (0101) and find the quotient

A. 100011
B. 101001
C. 110010
D. 010001
Answer» A. 100011
300.

Binary subtraction of 101101 – 001011 = ?

A. 100010
B. 010110
C. 110101
D. 101100
Answer» A. 100010
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