Digital Electronics Question & AnswersJune 5, 2021 By WatElectronics This Article lists 50+ Digital Electronics MCQs for engineering students. All the Digital Electronics Questions & Answers given below includes solution and link wherever possible to the relevant topic.Digital electronics are nothing but devices that operate or work with digital signals. The other names of digital electronics are digital circuits or digital logic or logic circuit design. The advantages of digital electronics are more reliable, accuracy is high, easy to design, flexibility is high, higher transmission rate, and more secure. Digital electronics covers number systems & codes, logic gates & boolean algebra, combinational & sequential circuits, logic families, semiconductor memories, analog to digital & digital to analog converters, and microprocessors. Some of the digital electronic devices are digital watches, digital audio players like MP3 players, digital cameras, digital toys, calculators, televisions, refrigerators, etc. 1). The binary number of decimal number 32 is _______(100000)2(101100)2(111111)2(010101)2HintThe decimal number 32 is represented as (100000)2 in binary format 2). _________ and ________ gates are universal gates?NAND and ANDNAND and NORNAND and ORNone of the aboveHintNOT, OR, and AND gates can be implemented by using these gates Read more about Universal Gates 3). Which gate is used to made IC decoders?NANDNORANDNone of the aboveHintThe gate which is used to made IC decoders is the NAND logic gate 4). Who invented Gray code?Frank GrayDom HofmannAryabhattaNone of the aboveHintGray code is a binary numerical system given by Frank Gray 5). How many OR gates are used to made encodersOneTwoThreeFourHintThe two OR gates are required to made encoders 6). In which gate the output is high when any one or all inputs are high?ANDNANDORNORHintThe OR gate is used to implement the OR operator, in this gate the output is high when anyone or all inputs are high 7). If the current is same for the different time then it is _____________Direct currentDiscrete currentAlternative currentNone of the aboveHintWhen the current is the same for a different time then the current is said to be direct current 8). The transducers converts _________Non-electrical signals into electrical signalsElectrical signals into non-electrical signalsElectrical signals into electromagnetic wavesNone of the aboveHintThe transducer is the device that is used to convert the non-electrical signals into electrical signals 9). Choose the odd one outWatchCalculatorComputerCoalHintThe watch, calculators, computers are the digital systems whereas coal doesn’t come under digital systems 10). ______________ is used in communication process to minimize the effect of noiseDigital signalAnalog signalElectrical signalNone of the aboveHintThe signal which is used in the communication process to reduce the effect of noise is a digital signal 11). What are the advantages of the digital systems?High-efficiencyUses less bandwidthEncryptionAll of the aboveHintThe digital system uses less bandwidth, encryption, and the efficiency is higher for long-distance transmission in the case of digital systems 12). The reverse transducer converts ___________Non-electrical signals into electrical signalsElectrical signals into non-electrical signalsElectrical signals into electromagnetic wavesNone of the aboveHintThe reverse transducer is the device that is used to convert the electrical signals into non-electrical signals 13). How many possibilities do two switches have?OneTwoThreeFourHintThe two switches have four possibilities they are ON-ON, ON-OFF, OFF - OFF, and OFF- ON 14). How many possibilities does two-bit number have?OneTwoThreeFourHintThe two-bit number has four possibilities they are 00, 01,10, and 11. 15). The number of switches is equal to the _______Number of digitsNumber of bytesNumber of bitsNone of the aboveHintThe number of switches is equal to the number of bits and the accuracy is directly proportional to the number of switches 16). The 8 bits is equal to the __________ bytesOne-byteTwo-bytesThree-bytesNone of the aboveHintEight bits is equal to one byte 17). The boolean algebra is given by _________Ronald J TocciPascalGeorge BooleNone of the aboveHintThe boolean algebra is given by George Boole in the year 1815 18). What is the standard form of PIPO?Parallel Input Parallel OutputParallel Output Parallel InputPositive Input Positive OutputNone of the aboveHintThe standard form of PIPO is Parallel Input Parallel Output 19). How many types of number systems are there?TwoThreeFourFiveHintThere are five types of number systems they are base, octal, decimal, duodecimal, and hexadecimal. 20). What is the base of octal?281210HintIn the case of octal, the base is 8, they are from 0 to (8-1) that is 0 to 7Digital Electronics MCQs For Exams 21). What are the examples of weighted number systems and code?DecimalBinaryOctalAll of the aboveHintThe decimal, binary, octal, binary-coded decimal, etc are the weighted number systems 22). What are the examples of un-weighted number systems and code?Gray codeExcess-3 codeBoth a and bNone of the aboveHintThe gray code and excess-3 code are examples of the un-weighted number systems and code 23). All real-life signals are ________ in natureDigitalAnalogDiscreteNone of the aboveHintAll real-life signals are analog in nature, the use of analog signal is much better as compared to digital signals because if we want a digital signal we need to convert the analog signal by using ADC 24). How many roles does Boolean Algebra have ______TwoThreeFourFiveHintThe Boolean algebra has five roles they are AND, OR, Complement, Distributive, and Demorgan’s law 25). What are the conditions of the redundancy theorem?Each variable is repeated twiceOne variable is complimentedTake the complimented variableAll of the aboveHintThe conditions of the redundancy theorem are there must be three variables, each variable is repeated twice, one variable is complimented, and take the complimented variable 26). What are the basic gates?ANDNOTORAll of the aboveHintAND, NOT, and OR is basic gates because we can implement any logic by using these basic gates. By using these three gates we can implement any digital circuit 27). In positive logic ________Higher voltage corresponds to logic 1Lower voltage corresponds to logic 0Both a and bNone of the aboveHintIn positive logic higher voltage corresponds to logic 1, and Lower voltage corresponds to logic 0. 28). What is the base of the hexadecimal number system?281016HintThe base of the hexadecimal number system is 16. The base of a number system is also called a radix (r) and the notation of base is r. 29). Hamming code is invented by ________1-bit2-bits3-bits4-bitsHintOne nibble is equal to 4 bits 30). How many bits does one nibble have _______1-bit2-bits3-bits4-bitsHintOne nibble is equal to 4 bits 31). The different names of gray code ___________Cyclic codeUnit distance codeMinimum error codeAll of the aboveHintGray code has different names it can also called cyclic, unit distance code, minimum error, and un-weighted code 32). The code is ________Group of bitsGroup of bytesGroup of digitsGroup of symbolsHintThe group of symbols is called code 33). The reflective code is also called as _________Diminished complement codeRadix complement codeSelf complement codeNone of the aboveHintThe reflective code is also called as self complement code 34). The r’s complement is also called as __________Radix complementDiminished complementDiminished radix complementNone of the aboveHintThe r’s complement is also called as radix complement 35). The (r-1)’s complement is also called as __________Radix complementDiminished complementDiminished radix complementNone of the aboveHintThe (r-1)’s complement is also called as diminished radix complement 36). ________ gate is a universal gateNOTNORANDExclusive ORHintNOR logic gate is a universal gate 37). The Gray code is also called as ________Complement codeBinary codeReflected codeReflected binary codeHintThe Gray code is also called reflected binary code 38). The parity is used to ________Increase the switching operationReduce switching operationDetect errorsNone of the aboveHintThe parity is used to detect the errors, parity detects only sing bit error 39). The logic gates are divided into ______ groupsOneTwoThreeFourHintThe logic gates are classified into three groups they are universal gate, basic gate, and arithmetic gate 40). What are the arithmetic gate?NAND and NORAND and NANDX-OR and X-NORNone of the aboveHintThe X-OR and X-NOR are the arithmetic gates because we use these gates in arithmetic operations.Digital Electronics Interview Questions 41). When all the inputs are high the output is also high in _______ gateANDNANDNORNone of the aboveHintAND gate is an electronic device that is used to implement AND operator, in this gate the output is high when all inputs are high 42). Gray code is used in __________ communicationAnalog communicationDigital communicationBoth analog and digitalNone of the aboveHintThe gray code is used in digital communication 43). The group of 1’s is also called as _____________ImplicantsPrime implicantsEssential prime implicantsNone of the aboveHintThe group of 1’s is also called implicants 44). In which circuit the output is dependent only on the present input ________Combinational circuitSequential circuitBoth a and bNone of the aboveHintIn a combinational circuit, the output is dependent only on the present input 45). How many types of codes are there _________OneTwoThreeSixHintThere are six types of codes they are weighted, un-weighted, reflective, sequential, alphanumeric, error detecting, and correcting codes 46). How many bits does one byte have?4 bits8 bits16 bits32 bitsHintOne byte is equal to 8 bits 47). How many bits does one word have?4 bits8 bits16 bits32 bitsHintOne word is equal to 16 bits 48). In __________ implicants there is at least a single 1 which cannot be combined in any other wayPrime implicantsEssential implicantsEssential prime implicantsNone of the aboveHintIn essential prime implicants, there is at least a single 1 which cannot be combined in any other way 49). In which circuit the output is dependent on the present input as well as previous output or outputsCombinational circuitSequential circuitBoth a and bNone of the aboveHintIn a sequential circuit, the output is dependent on the present input as well as previous output or outputs 50). In negative logic ________Higher voltage corresponds to logic 0Lower voltage corresponds to logic 1Both a and bNone of the aboveHintIn negative logic higher voltage corresponds to logic 0 and the lower voltage corresponds to logic 1 51). In digital signals we descritise ___________TimeMagnitudeBoth time and magnitudeNone of the aboveHintIn digital signals, we descritise both time and magnitude 52). ____________ is the signal which is defined for the discrete interval of timeAnalog signalDigital signalDiscrete time signalNone of the aboveHintThe discrete-time signal is the signal which is defined for the discrete interval of time 53). What is the base of hexadecimal _______16832None of the aboveHintIn case of hexadecimal number the base is 16, and they are from 0 to (16-1) that is 0,1,2,……9, A,B,C,D,E,F 54). What is the base of duodecimal _______12832None of the aboveHintIn the case of a duodecimal number, the base is 12, and they are from 0 to (12-1) 55). The number systems and codes are categorized into how many groups?OneTwoThreeFourHintThe number systems and codes are categorized into two groups they are weighted number systems and un-weighted number systems 56). The counter is used to count the number of ______DigitsBitsPulsesNone of the aboveHintThe counter is a digital device which is generally used for counting purpose, it counts the number of pulses whatever the clock pulse we give 57). In how many ways counter can count the pulses?OneTwoThreeFourHintThe counter can count the pulses in two ways, for example, it may count from 0,1,2……N that is called as up count or it may count in a downward direction also that is from N, N-1, N-2….…..1,0 58). What is the formula for the n-bit counter?Each state frequency= total frequency/2nEach state frequency= total frequency.2nEach state frequency= total frequency.2n+1None of the aboveHintThe formula for the n-bit counter is each state frequency is equal to the total frequency of the counter divided by the number of states (2n) 59). What is the formula to obtain the number of parity bits?2P ≥ P+m+12P ≥ P+m-12P ≥ P-m-1None of the aboveHintThe formula which is used to obtain the number of bits is 2P ≥ P+m+1, where m is the number of message bits and P is the parity bits 60). What is the formula to convert any other number system to a decimal number system?Ʃdigit*nƩdigit/npvƩdigit*npvNone of the aboveHintThe formula which is used to convert any other number system to a decimal number system is Ʃdigit*npvDigital Electronics Important MCQs for Quiz 61). The speed of the synchronous counter is _______Higher than asynchronous counterLower than the asynchronous counterEqual to asynchronous counterNone of the aboveHintThe speed of the synchronous counter is higher than the asynchronous counter because all flip-flops operating simultaneously as the flip-flop is given at the same time Read more about Digital Counters 62). How many MOS transistors are required to form SRAM?6-84-64-8None of the aboveHintThe MOS transistors required to form SRAM cell is nearly 6-8. Read more about Transistors 63). Which one belongs to a bipolar saturated logic family?Resistor Transistor Logic (RTL)Direct Coupled Transistor Logic(DCTL)Integration Injection Logic (IIL)All of the aboveHintThe RTL, DCTL, and IIL logics have belonged to a bipolar logic family 64). Which one belongs to a unipolar logic family?PMOSCMOSECLBoth a and bHintThe p-channel metal oxide semiconductor and complementary metal-oxide-semiconductor belongs to a unipolar logic family 65). _____ comes under unipolar logic familyPMOSCMOSNMOSAll of the aboveHintThe P-channel, N-channel, and complementary metal-oxide semiconductors come under the unipolar logic family 66). The base or radix represents _________Number of bitsNumber of digitsNumber of symbolsAll of the aboveHintThe base or radix is nothing but the value that represents the particular number system. It specially defines the number of bits, digits, letters, and symbols in a particular number system. 67). What are the complements used for subtraction?Binary subtractionHexadecimal subtractionBCD & Excess-3 subtractionAll of the aboveHintThe complements used for subtraction are binary, hexadecimal, BCD, and excess-3 subtraction. 68). DRAM stores single bit by using __________TransistorCapacitorBoth a and bNone of the aboveHintDRAM stores single bit by using both transistor and capacitor 69). The Schottky TTL and ECL (Emitter Coupled Logic) comes under which logic family?Bipolar saturated logic familyBipolar unsaturated logic familyUnipolar logic familyNone of the aboveHintThe Schottky transistor logic and emitter-coupled logic comes under a bipolar unsaturated logic family. 70). The components used in DTL logic are ________Diode, transistorDiode, resistorDiode, transistor, resistorNone of the aboveHintThe components used in DTL logic are diodes, transistors, and resistors 71). Which code comes under unweighted, sequential, and reflective code?Binary codeGray codeExcess-3BCDHintThe excess-3 code comes under all unweighted, sequential, and reflective binary code 72). How many MOS transistors are required to form a single cell of DRAM?2345HintFour MOS transistors are required to form a single cell of the DRAM 73). Four transistors are required to form a single cell DRAMTrueFalseHintFour MOS transistors are required to form a single cell of a DRAM 74). How much data the shift register can store?Only oneOnly twoOnly threeNone of the aboveHintThe shift registers can store the data depends upon the number of flip flops 75). The flip flop is a ______1-bit memory cell2-bit memory cell4-bit memory cell8-bit memory cellHintThe flip flop stores only 1 or 0, so it is called a single bit memory cell Read more about Flipflops 76). The group of flip flops is also known as __________RegistersCountersEncodersNone of the aboveHintThe group of flip flops is used to increase the storage capacity, and the group of flip flops also called a registers 77). The Karnaugh map is developed in which year?1951195219531954HintThe Karnaugh map is developed in 1953 by the karnaugh and it is used to simply the Boolean algebraic expressions without using Boolean laws. 78). The half adder consists _________One input one outputOne input two outputsTwo inputs two outputsTwo inputs one outputHintThe half adder consists of two inputs and two outputs, the two outputs may be the sum and carry 79). The output of the multiplexer depends on its _____Data outputsData inputsSelected inputsNone of the aboveHintThe multiplexer output depends on the selected inputs because whenever the selected input changes according that the multiplexer output will also vary 80). ASCII comes under which binary code?AlphanumericReflectiveSequentialError detecting and correctingHintThe ASCII comes under alphanumeric code, alphanumeric is one of the binary code 81). The output of the sequential circuit depends on ______Present inputPresent input and present statePresent stateNone of the aboveHintThe output of the sequential circuit always depends upon the present input and present state, present state implies past input or past output 82). Where do all the bios settings and configuration details get to store?CMOSPMOSNMOSNone of the aboveHintAll bios settings and configuration details get store in CMOS memory 83). The other names CMOS are ________CMOS memoryCMOS batteryNon-volatile BIOS memoryAll of the aboveHintIn normal terms, we also call CMOS as CMOS memory or CMOS memory, or a non-volatile BIOS memory 84). The Field Effect Transistor is __________ deviceSingle terminal deviceDouble terminal deviceThree terminal deviceNone of the aboveHintThe Field Effect Transistor or FET is a three-terminal device, the three terminals namely gate, source, and drain Time is Up!