Digital Electronics Question & Answers June 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 Hint 2). _________ and ________ gates are universal gates? NAND and AND NAND and NOR NAND and OR None of the above Hint Read more about Universal Gates 3). Which gate is used to made IC decoders? NAND NOR AND None of the above Hint 4). Who invented Gray code? Frank Gray Dom Hofmann Aryabhatta None of the above Hint 5). How many OR gates are used to made encoders One Two Three Four Hint 6). In which gate the output is high when any one or all inputs are high? AND NAND OR NOR Hint 7). If the current is same for the different time then it is _____________ Direct current Discrete current Alternative current None of the above Hint 8). The transducers converts _________ Non-electrical signals into electrical signals Electrical signals into non-electrical signals Electrical signals into electromagnetic waves None of the above Hint 9). Choose the odd one out Watch Calculator Computer Coal Hint 10). ______________ is used in communication process to minimize the effect of noise Digital signal Analog signal Electrical signal None of the above Hint 11). What are the advantages of the digital systems? High-efficiency Uses less bandwidth Encryption All of the above Hint 12). 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 Hint 13). How many possibilities do two switches have? One Two Three Four Hint 14). How many possibilities does two-bit number have? One Two Three Four Hint 15). The number of switches is equal to the _______ Number of digits Number of bytes Number of bits None of the above Hint 16). The 8 bits is equal to the __________ bytes One-byte Two-bytes Three-bytes None of the above Hint 17). The boolean algebra is given by _________ Ronald J Tocci Pascal George Boole None of the above Hint 18). What is the standard form of PIPO? Parallel Input Parallel Output Parallel Output Parallel Input Positive Input Positive Output None of the above Hint 19). How many types of number systems are there? Two Three Four Five Hint 20). What is the base of octal? 2 8 12 10 Hint Digital Electronics MCQs For Exams 21). What are the examples of weighted number systems and code? Decimal Binary Octal All of the above Hint 22). What are the examples of un-weighted number systems and code? Gray code Excess-3 code Both a and b None of the above Hint 23). All real-life signals are ________ in nature Digital Analog Discrete None of the above Hint 24). How many roles does Boolean Algebra have ______ Two Three Four Five Hint 25). 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 Hint 26). What are the basic gates? AND NOT OR All of the above Hint 27). In positive logic ________ Higher voltage corresponds to logic 1 Lower voltage corresponds to logic 0 Both a and b None of the above Hint 28). What is the base of the hexadecimal number system? 2 8 10 16 Hint 29). Hamming code is invented by ________ 1-bit 2-bits 3-bits 4-bits Hint 30). How many bits does one nibble have _______ 1-bit 2-bits 3-bits 4-bits Hint 31). The different names of gray code ___________ Cyclic code Unit distance code Minimum error code All of the above Hint 32). The code is ________ Group of bits Group of bytes Group of digits Group of symbols Hint 33). The reflective code is also called as _________ Diminished complement code Radix complement code Self complement code None of the above Hint 34). The r’s complement is also called as __________ Radix complement Diminished complement Diminished radix complement None of the above Hint 35). The (r-1)’s complement is also called as __________ Radix complement Diminished complement Diminished radix complement None of the above Hint 36). ________ gate is a universal gate NOT NOR AND Exclusive OR Hint 37). The Gray code is also called as ________ Complement code Binary code Reflected code Reflected binary code Hint 38). The parity is used to ________ Increase the switching operation Reduce switching operation Detect errors None of the above Hint 39). The logic gates are divided into ______ groups One Two Three Four Hint 40). What are the arithmetic gate? NAND and NOR AND and NAND X-OR and X-NOR None of the above Hint Digital Electronics Interview Questions 41). When all the inputs are high the output is also high in _______ gate AND NAND NOR None of the above Hint 42). Gray code is used in __________ communication Analog communication Digital communication Both analog and digital None of the above Hint 43). The group of 1’s is also called as _____________ Implicants Prime implicants Essential prime implicants None of the above Hint 44). In which circuit the output is dependent only on the present input ________ Combinational circuit Sequential circuit Both a and b None of the above Hint 45). How many types of codes are there _________ One Two Three Six Hint 46). How many bits does one byte have? 4 bits 8 bits 16 bits 32 bits Hint 47). How many bits does one word have? 4 bits 8 bits 16 bits 32 bits Hint 48). 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 Hint 49). 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 Hint 50). In negative logic ________ Higher voltage corresponds to logic 0 Lower voltage corresponds to logic 1 Both a and b None of the above Hint 51). In digital signals we descritise ___________ Time Magnitude Both time and magnitude None of the above Hint 52). ____________ is the signal which is defined for the discrete interval of time Analog signal Digital signal Discrete time signal None of the above Hint 53). What is the base of hexadecimal _______ 16 8 32 None of the above Hint 54). What is the base of duodecimal _______ 12 8 32 None of the above Hint 55). The number systems and codes are categorized into how many groups? One Two Three Four Hint 56). The counter is used to count the number of ______ Digits Bits Pulses None of the above Hint 57). In how many ways counter can count the pulses? One Two Three Four Hint 58). 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 Hint 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 Hint 60). 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 Hint Digital Electronics Important MCQs for Quiz 61). The speed of the synchronous counter is _______ Higher than asynchronous counter Lower than the asynchronous counter Equal to asynchronous counter None of the above Hint Read more about Digital Counters 62). How many MOS transistors are required to form SRAM? 6-8 4-6 4-8 None of the above Hint 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 above Hint 64). Which one belongs to a unipolar logic family? PMOS CMOS ECL Both a and b Hint 65). _____ comes under unipolar logic family PMOS CMOS NMOS All of the above Hint 66). The base or radix represents _________ Number of bits Number of digits Number of symbols All of the above Hint 67). What are the complements used for subtraction? Binary subtraction Hexadecimal subtraction BCD & Excess-3 subtraction All of the above Hint 68). DRAM stores single bit by using __________ Transistor Capacitor Both a and b None of the above Hint 69). 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 Hint 70). The components used in DTL logic are ________ Diode, transistor Diode, resistor Diode, transistor, resistor None of the above Hint 71). Which code comes under unweighted, sequential, and reflective code? Binary code Gray code Excess-3 BCD Hint 72). How many MOS transistors are required to form a single cell of DRAM? 2 3 4 5 Hint 73). Four transistors are required to form a single cell DRAM True False Hint 74). How much data the shift register can store? Only one Only two Only three None of the above Hint 75). The flip flop is a ______ 1-bit memory cell 2-bit memory cell 4-bit memory cell 8-bit memory cell Hint Read more about Flipflops 76). The group of flip flops is also known as __________ Registers Counters Encoders None of the above Hint 77). The Karnaugh map is developed in which year? 1951 1952 1953 1954 Hint 78). The half adder consists _________ One input one output One input two outputs Two inputs two outputs Two inputs one output Hint 79). The output of the multiplexer depends on its _____ Data outputs Data inputs Selected inputs None of the above Hint 80). ASCII comes under which binary code? Alphanumeric Reflective Sequential Error detecting and correcting Hint 81). The output of the sequential circuit depends on ______ Present input Present input and present state Present state None of the above Hint 82). Where do all the bios settings and configuration details get to store? CMOS PMOS NMOS None of the above Hint 83). The other names CMOS are ________ CMOS memory CMOS battery Non-volatile BIOS memory All of the above Hint 84). The Field Effect Transistor is __________ device Single terminal device Double terminal device Three terminal device None of the above Hint Time's up