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.The signal which is used in the communication process to reduce the effect of noise is digital. The watch, calculators, computers are the digital systems whereas coal doesn’t come under digital systems. The transducer is the device that is used to convert the non-electrical signals into electrical signals. When the current is the same for a different time then the current is said to be direct current. The OR gate is used to implement the OR operator, in this gate the output is high when one input or all inputs are high. The NAND and NOR logic gates are universal because the basic gates such as NOT, OR, and AND gates can be implemented by using only the universal gates.1). The binary number of decimal number 32 is _______ (100000)2 (101100)2 (111111)2 (010101)2 HintThe decimal number 32 is represented as (100000)2 in binary format2). _________ and ________ gates are universal gates? NAND and AND NAND and NOR NAND and OR None of the above HintNOT, 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? NAND NOR AND None of the above HintThe gate which is used to made IC decoders is the NAND logic gate4). Who invented Gray code? Frank Gray Dom Hofmann Aryabhatta None of the above HintGray code is a binary numerical system given by Frank Gray 5). How many OR gates are used to made encoders One Two Three Four HintThe two OR gates are required to made encoders6). In which gate the output is high when any one or all inputs are high? AND NAND OR NOR HintThe OR gate is used to implement the OR operator, in this gate the output is high when anyone or all inputs are high7). If the current is same for the different time then it is _____________ Direct current Discrete current Alternative current None of the above HintWhen the current is the same for a different time then the current is said to be direct current8). The transducers converts _________ Non-electrical signals into electrical signals Electrical signals into non-electrical signals Electrical signals into electromagnetic waves None of the above HintThe transducer is the device that is used to convert the non-electrical signals into electrical signals9). Choose the odd one out Watch Calculator Computer Coal HintThe watch, calculators, computers are the digital systems whereas coal doesn’t come under digital systems10). ______________ is used in communication process to minimize the effect of noise Digital signal Analog signal Electrical signal None of the above HintThe signal which is used in the communication process to reduce the effect of noise is a digital signal11). What are the advantages of the digital systems? High-efficiency Uses less bandwidth Encryption All of the above HintThe digital system uses less bandwidth, encryption, and the efficiency is higher for long-distance transmission in the case of digital systems12). The reverse transducer converts ___________ Non-electrical signals into electrical signals Electrical signals into non-electrical signals Electrical signals into electromagnetic waves None of the above HintThe reverse transducer is the device that is used to convert the electrical signals into non-electrical signals13). How many possibilities do two switches have? One Two Three Four HintThe two switches have four possibilities they are ON-ON, ON-OFF, OFF - OFF, and OFF- ON14). How many possibilities does two-bit number have? One Two Three Four HintThe two-bit number has four possibilities they are 00, 01,10, and 11.15). The number of switches is equal to the _______ Number of digits Number of bytes Number of bits None of the above HintThe number of switches is equal to the number of bits and the accuracy is directly proportional to the number of switches16). The 8 bits is equal to the __________ bytes One-byte Two-bytes Three-bytes None of the above HintEight bits is equal to one byte17). The boolean algebra is given by _________ Ronald J Tocci Pascal George Boole None of the above HintThe boolean algebra is given by George Boole in the year 181518). What is the standard form of PIPO? Parallel Input Parallel Output Parallel Output Parallel Input Positive Input Positive Output None of the above HintThe standard form of PIPO is Parallel Input Parallel Output19). How many types of number systems are there? Two Three Four Five HintThere are five types of number systems they are base, octal, decimal, duodecimal, and hexadecimal.20). What is the base of octal? 2 8 12 10 HintIn the case of octal, the base is 8, they are from 0 to (8-1) that is 0 to 7Digital Electronics MCQs For Exams21). What are the examples of weighted number systems and code? Decimal Binary Octal All of the above HintThe decimal, binary, octal, binary-coded decimal, etc are the weighted number systems22). What are the examples of un-weighted number systems and code? Gray code Excess-3 code Both a and b None of the above HintThe gray code and excess-3 code are examples of the un-weighted number systems and code23). All real-life signals are ________ in nature Digital Analog Discrete None of the above HintAll 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 ADC24). How many roles does Boolean Algebra have ______ Two Three Four Five HintThe Boolean algebra has five roles they are AND, OR, Complement, Distributive, and Demorgan’s law25). What are the conditions of the redundancy theorem? Each variable is repeated twice One variable is complimented Take the complimented variable All of the above HintThe conditions of the redundancy theorem are there must be three variables, each variable is repeated twice, one variable is complimented, and take the complimented variable26). What are the basic gates? AND NOT OR All of the above HintAND, 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 circuit27). In positive logic ________ Higher voltage corresponds to logic 1 Lower voltage corresponds to logic 0 Both a and b None of the above HintIn 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? 2 8 10 16 HintThe 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-bit 2-bits 3-bits 4-bits HintOne nibble is equal to 4 bits30). How many bits does one nibble have _______ 1-bit 2-bits 3-bits 4-bits HintOne nibble is equal to 4 bits31). The different names of gray code ___________ Cyclic code Unit distance code Minimum error code All of the above HintGray code has different names it can also called cyclic, unit distance code, minimum error, and un-weighted code32). The code is ________ Group of bits Group of bytes Group of digits Group of symbols HintThe group of symbols is called code33). The reflective code is also called as _________ Diminished complement code Radix complement code Self complement code None of the above HintThe reflective code is also called as self complement code34). The r’s complement is also called as __________ Radix complement Diminished complement Diminished radix complement None of the above HintThe r’s complement is also called as radix complement35). The (r-1)’s complement is also called as __________ Radix complement Diminished complement Diminished radix complement None of the above HintThe (r-1)’s complement is also called as diminished radix complement 36). ________ gate is a universal gate NOT NOR AND Exclusive OR HintNOR logic gate is a universal gate37). The Gray code is also called as ________ Complement code Binary code Reflected code Reflected binary code HintThe Gray code is also called reflected binary code38). The parity is used to ________ Increase the switching operation Reduce switching operation Detect errors None of the above HintThe parity is used to detect the errors, parity detects only sing bit error39). The logic gates are divided into ______ groups One Two Three Four HintThe logic gates are classified into three groups they are universal gate, basic gate, and arithmetic gate40). What are the arithmetic gate? NAND and NOR AND and NAND X-OR and X-NOR None of the above HintThe X-OR and X-NOR are the arithmetic gates because we use these gates in arithmetic operations.Digital Electronics Interview Questions41). When all the inputs are high the output is also high in _______ gate AND NAND NOR None of the above HintAND gate is an electronic device that is used to implement AND operator, in this gate the output is high when all inputs are high42). Gray code is used in __________ communication Analog communication Digital communication Both analog and digital None of the above HintThe gray code is used in digital communication43). The group of 1’s is also called as _____________ Implicants Prime implicants Essential prime implicants None of the above HintThe group of 1’s is also called implicants44). In which circuit the output is dependent only on the present input ________ Combinational circuit Sequential circuit Both a and b None of the above HintIn a combinational circuit, the output is dependent only on the present input45). How many types of codes are there _________ One Two Three Six HintThere are six types of codes they are weighted, un-weighted, reflective, sequential, alphanumeric, error detecting, and correcting codes46). How many bits does one byte have? 4 bits 8 bits 16 bits 32 bits HintOne byte is equal to 8 bits47). How many bits does one word have? 4 bits 8 bits 16 bits 32 bits HintOne word is equal to 16 bits48). In __________ implicants there is at least a single 1 which cannot be combined in any other way Prime implicants Essential implicants Essential prime implicants None of the above HintIn essential prime implicants, there is at least a single 1 which cannot be combined in any other way49). In which circuit the output is dependent on the present input as well as previous output or outputs Combinational circuit Sequential circuit Both a and b None of the above HintIn 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 0 Lower voltage corresponds to logic 1 Both a and b None of the above HintIn negative logic higher voltage corresponds to logic 0 and the lower voltage corresponds to logic 151). In digital signals we descritise ___________ Time Magnitude Both time and magnitude None of the above HintIn digital signals, we descritise both time and magnitude52). ____________ is the signal which is defined for the discrete interval of time Analog signal Digital signal Discrete time signal None of the above HintThe discrete-time signal is the signal which is defined for the discrete interval of time53). What is the base of hexadecimal _______ 16 8 32 None of the above HintIn 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,F54). What is the base of duodecimal _______ 12 8 32 None of the above HintIn 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? One Two Three Four HintThe number systems and codes are categorized into two groups they are weighted number systems and un-weighted number systems56). The counter is used to count the number of ______ Digits Bits Pulses None of the above HintThe counter is a digital device which is generally used for counting purpose, it counts the number of pulses whatever the clock pulse we give57). In how many ways counter can count the pulses? One Two Three Four HintThe 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….…..1,058). What is the formula for the n-bit counter? Each state frequency= total frequency/2n Each state frequency= total frequency.2n Each state frequency= total frequency.2n+1 None of the above HintThe 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+1 2P ≥ P+m-1 2P ≥ P-m-1 None of the above HintThe 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 bits60). What is the formula to convert any other number system to a decimal number system? Ʃdigit*n Ʃdigit/npv Ʃdigit*npv None of the above HintThe formula which is used to convert any other number system to a decimal number system is Ʃdigit*npvDigital Electronics Important MCQs for Quiz61). The speed of the synchronous counter is _______ Higher than asynchronous counter Lower than the asynchronous counter Equal to asynchronous counter None of the above HintThe 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 Counters62). How many MOS transistors are required to form SRAM? 6-8 4-6 4-8 None of the above HintThe MOS transistors required to form SRAM cell is nearly 6-8. Read more about Transistors63). 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 above HintThe RTL, DCTL, and IIL logics have belonged to a bipolar logic family64). Which one belongs to a unipolar logic family? PMOS CMOS ECL Both a and b HintThe p-channel metal oxide semiconductor and complementary metal-oxide-semiconductor belongs to a unipolar logic family65). _____ comes under unipolar logic family PMOS CMOS NMOS All of the above HintThe P-channel, N-channel, and complementary metal-oxide semiconductors come under the unipolar logic family66). The base or radix represents _________ Number of bits Number of digits Number of symbols All of the above HintThe 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 subtraction Hexadecimal subtraction BCD & Excess-3 subtraction All of the above HintThe complements used for subtraction are binary, hexadecimal, BCD, and excess-3 subtraction.68). DRAM stores single bit by using __________ Transistor Capacitor Both a and b None of the above HintDRAM stores single bit by using both transistor and capacitor69). The Schottky TTL and ECL (Emitter Coupled Logic) comes under which logic family? Bipolar saturated logic family Bipolar unsaturated logic family Unipolar logic family None of the above HintThe Schottky transistor logic and emitter-coupled logic comes under a bipolar unsaturated logic family. 70). The components used in DTL logic are ________ Diode, transistor Diode, resistor Diode, transistor, resistor None of the above HintThe components used in DTL logic are diodes, transistors, and resistors71). Which code comes under unweighted, sequential, and reflective code? Binary code Gray code Excess-3 BCD HintThe excess-3 code comes under all unweighted, sequential, and reflective binary code72). How many MOS transistors are required to form a single cell of DRAM? 2 3 4 5 HintFour MOS transistors are required to form a single cell of the DRAM73). Four transistors are required to form a single cell DRAM True False HintFour MOS transistors are required to form a single cell of a DRAM74). How much data the shift register can store? Only one Only two Only three None of the above HintThe shift registers can store the data depends upon the number of flip flops75). The flip flop is a ______ 1-bit memory cell 2-bit memory cell 4-bit memory cell 8-bit memory cell HintThe flip flop stores only 1 or 0, so it is called a single bit memory cell Read more about Flipflops76). The group of flip flops is also known as __________ Registers Counters Encoders None of the above HintThe group of flip flops is used to increase the storage capacity, and the group of flip flops also called a registers77). The Karnaugh map is developed in which year? 1951 1952 1953 1954 HintThe 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 output One input two outputs Two inputs two outputs Two inputs one output HintThe half adder consists of two inputs and two outputs, the two outputs may be the sum and carry79). The output of the multiplexer depends on its _____ Data outputs Data inputs Selected inputs None of the above HintThe multiplexer output depends on the selected inputs because whenever the selected input changes according that the multiplexer output will also vary80). ASCII comes under which binary code? Alphanumeric Reflective Sequential Error detecting and correcting HintThe ASCII comes under alphanumeric code, alphanumeric is one of the binary code81). The output of the sequential circuit depends on ______ Present input Present input and present state Present state None of the above HintThe output of the sequential circuit always depends upon the present input and present state, present state implies past input or past output82). Where do all the bios settings and configuration details get to store? CMOS PMOS NMOS None of the above HintAll bios settings and configuration details get store in CMOS memory83). The other names CMOS are ________ CMOS memory CMOS battery Non-volatile BIOS memory All of the above HintIn normal terms, we also call CMOS as CMOS memory or CMOS memory, or a non-volatile BIOS memory84). The Field Effect Transistor is __________ device Single terminal device Double terminal device Three terminal device None of the above HintThe Field Effect Transistor or FET is a three-terminal device, the three terminals namely gate, source, and drain Time is Up! Time's up