Multiple choice questions and answers on logic gates. Digital electronics part i combinational and sequential. Vhdl programming combinational circuits this chapter explains the vhdl programming for combinational circuits. Digital logic design multiple choice questions and answers mcqs pdf is a revision guide with a collection of trivia quiz questions and answers pdf on topics. Total 25 questions have been asked from combinational and sequential logic circuits topic of analog and digital electronics subject in previous gate papers. Digital computers consist of the digital logic circuits. First, invert d then use and gates for and then use an or gate for finally, and together the outputs of the inputs and or gate. These circuits employ storage elements and logic gates. Then, simplify the circuit s much as possible using algebra. Download it once and read it on your kindle device, pc, phones or tablets. The date of birth will be displayed in the mmddyy format. Learners will investigate the characteristics and applications of combinational and sequential logic devices. A combinational circuit consists of input variables n, logic gates, and output variables m.
Combinational logics multiple choice questions and answers. Block diagram were going to elaborate few important combinational circuits as follows. These logic circuits are formed by connecting one or more logic gates together. These functions can be described using logic expressions, but is most often at least initially using truth tables. An example of a combinational circuit is a decoder, which converts the binary code data present at its input into a number of different output lines, one at a time producing an equivalent decimal code at its output. In combinational circuits, the output exists as long as the input exists.
Digital electronics questions and answers pdf free download. In mathematical terms, the each output is a function of the inputs. With combinational logic, the inputs will immediately determine what is in the output and these are the circuits well be looking at in 152. Obtain the simplified expression in sum of products for the following boolean functions.
Digital logic design multiple choice questions and answers pdf is a revision guide with a collection of trivia questions to fun quiz questions and answers pdf on topics. Railways students definitely take this combinational logic circuits mcq test exercise for a better result in the exam. Both latches and flipflops are circuit elements whose output depends not only on the current inputs, but. Q 1 consider the multiplexer based logic circuit shown in the figure. Multiple choice questions on combinational logic circuits. Combinational circuit 7 communication 22 computer networking 73 conversion rate optimization.
Combinational logic circuits are characterized by outputs that depend only on the actual input values. Design a 4bit combinational circuit decremented using four full adders. Combinational and sequential logic circuits analog and. Combinational and sequential logic are the fundamental building blocks of digital electronics. Tajana simunic rosing winter 2009 do not start the exam until you are told to. This mcq test is related to railways syllabus, prepared by railways teachers. In a sequential logic circuit the outputs depend on the inputs plus. Algorithmic state machine, asynchronous sequential logic, binary systems, boolean algebra and logic gates, combinational logics, digital integrated circuits, dld experiments, msi and pld. Use features like bookmarks, note taking and highlighting while reading digital logic design mcqs. Digital electronics mcqs pdf solved questions bank for gate. Design a circuit that counts the number of 1s present in 3 inputs a, b and c. For each possible input combination there is one and only one possible output combination, a combinational circuit can be.
Operation of combinational gates over the inputs b. Combinational and sequential circuits digital logic. Logic gates worksheet truth tables label these basic logic gates and fill in their truth tables. Submit your answers and see how many you get right. Which of the following logic expressions represents the logic diagram shown. The term combination logic means combining of two or more logic gates to form a required function where the output at a given time depends only on the input.
Which is the correct sequential order of operational steps executed in the combinational logic circuits. For the design of combinational digital circuits basic and, or, not or universal gates gates nand, nor are. Free inductivelogical test questions with questions and answers jobtestprep invites you to a free practice session that represents only some of the materials offered in our online practice packs. Introduction to digital logic with laboratory exercises. Then you can start reading kindle books on your smartphone, tablet, or computer no kindle device required. Difference between combinational and sequential circuits. Digital logic design mcqs by arshad iqbal overdrive. Combinational circuits i adders, decoders, multiplexers cc are circuits without memory where the outputs are obtained from the inputs only. Show the logic circuit for this boolean equation y a. Combinational circuits digital circuits questions and answers. Sequential circuits need a way to sequence operations. Combinational circuits are logic circuits whose outputs respond immediately to the inputs. We have also provided number of questions asked since 2007 and average weightage for each subject. The basic properties of boolean algebra are commutative property, associative property and distributive property.
Next simplify this boolean equation and the corresponding circuit. Digital logic design mcqs pdf helps with theoretical, conceptual, and analytical study for selfassessment, career tests. Half adder half adder is a combinational logic circuit with two inputs and two outputs. Combinational logic circuits mcq test 20 questions mcq. In digital circuit theory, combinational logic sometimes also referred to as timeindependent logic is a type of digital logic which is implemented by boolean circuits, where the output is a pure function of the present input only. Apr 28, 2015 in this article we will discuss combinational logic circuit vs. The two characteristics of combinational circuits are. Multiple choice questions on sequential logic circuits. Combinational logic circuits circuits without a memory. Digital integrated circuits combinational logic prentice hall 1995 analysis of propagation delay v dd cl f rp rp rn rn a a b b 2input nand 1. Practice these mcq questions and answers for preparation of various competitive and entrance exams. Combinational circuit is a circuit in which we combine the different gates in the circuit, for example encoder, decoder, multiplexer and demultiplexer.
Algorithmic state machine, asynchronous sequential logic, binary systems, boolean algebra and logic gates, combinational logics, digital integrated circuits, dld experiments. If we use one of these four gates at first level and one at the second level then we get a total of 16 combinations of twolevel logic. A combinational logic circuit implement logical functions where its outputs depend only on its current combination of input values. A logic device that changes its output state in response to a high or low level of. This is a closedbook, closednotes, no calculator exam.
Generation of m different outputs as per the required level. Analysis procedure n to obtain the output boolean functions from a logic diagram, proceed as follows. The following section consists of multiple choice questions on combinational logic circuits. What is the boolean expression for the output f of the combinational logic circuit. For twolevel logic implementation, we consider four logic gates i. Combinational logic design i electronic engineering mcq. Combinational logic, which is sometimes referred to as combinatorial logic, is characterized by its output being a function of the current input value. Combinational logic circuits do not have an internal. Combinational logic a combinational system device is a digital system in which the value of the output at any instant depends only on the value of the input at that same instant and not on previous values.
Digital electronics objective type multiple choice interview questions 2 mark important lab viva manual. The purpose of this lab report is to teach the student how to apply the use of multiplexers to implement a boolean expression. Use the cutepdf printer driver to send the print job to a. Which sequential circuits generate the feedback path due to the crosscoupled connection from output of one gate to the input of another gate. It addresses all aspects of combinational logic and provides a detailed understanding of logic gates that are the basic components in the implementation of circuits used to perform functions and operations of boolean algebra. This test is rated positive by 90% students preparing for railways. Gate 2019 cse syllabus contains engineering mathematics, digital logic, computer organization and architecture, programming and data structures, algorithms, theory of computation, compiler design, operating system, databases, computer networks, general aptitude. Shann 22 chapter overview 21 binary logic and gates 22 boolean algebra 23 standard forms. In this type of logic circuits outputs depend on the current inputs and previous inputs. In the last experiment, the logic circuits introduced were combinational. A ninput moutput combinational circuit is of the form.
The half adder circuit is designed to add two single bit binary number a and b. These logic gates are the building blocks of combinational logic circuits. Practice mcqs with combinational logics quiz questions and answers for digital logic designtests. Also, applying the use of boolean algebra to implement a combination of 4 to 1 multiplexers to respond as an 8 to 1 multiplexer. The main difference between sequential circuits and combinational circuits is that sequential circuits compute their output. Apr 22,2020 combinational logic circuits mcq test 20 questions mcq test has questions of railways preparation. They will then design, construct and test combinational and sequential circuits and will use relevant computer software to simulate and verify circuits. Try our quiz, based on the information you can find in digital electronics module 4 combinational logic. Combinational circuits digital circuits questions and. If you get any answers wrong, just follow the hints to find the right answer and learn about the combinational logic circuits as you go. Digital logic design mcqs guide books acm digital library. Memory cells are very important in digital systems. Combinational logics questions mcqslearn free videos. This is in contrast to sequential logic, in which the output depends not only on the present input but also on the history of the input.
Take the quiz and improve your overall engineering. Ee6301 digital logic circuits two mark questions with answers uniti numbering systems and digital logic families 1 what are basic properties of boolean algebra. In this type of logic circuits outputs depend only on the current inputs. A combinational logic circuit is one in which the present state of the combination of the logic inputs decides the output. Algorithmic state machine, asynchronous sequential logic, binary systems, boolean algebra and logic gates, combinational logics, digital integrated circuits, dld experiments, msi and. For some 8bit data words, the following hamming code words are received. Design a combinational logic circuit that has three inputs and seven outputs. Combinational and sequential logic circuits hardware implementation and software design i. Combinational and sequential circuits proprofs quiz. Combinational and sequential logic circuits hardware. Combinational logic circuits iii purpose and objectives. Static cmos circuit at every point in time except during the switching transients each gate output is connected to either v dd or v ss via a lowresistive path the outputs of the gates assume at all times the value of the boolean function, implemented by the circuit in contrast, a dynamic circuit.
Piyush importance meter multiplexers question solving i. Cse 140l final exam university of california, san diego. To familiarize with combinational and sequential logic circuits. Binary counters simple design b bits can count from 0 to 2b. Use the order of precedence for and, or, and parentheses. Aug 23, 2017 in this video, i have discussed important mcqs based on sequential circuits which are very useful for your all upcoming examination like ssc imd, ntro, nielit, gate, ies etc. Modeling combinational logic as a processall signals referenced in process must be in the sensitivity list. An example of a combinational circuit is a decoder, which converts the binary code data present at its input into a. Combine the and, or, and inverter gates to create expression. A clock is created to be used in a basic state machine design that aims to combine logic circuits with memory. This textbook covers latest topics in the field of digital logic design along with tools to design the digital logic circuits. Vhdl programming combinational circuits tutorialspoint. Sample of the study material part of chapter 5 combinational. Combinational logic gates in cmos purdue engineering.
All students, freshers can download electronics combinational logic circuits quiz questions with answers as pdf files and ebooks. In a combinational circuit, the output depends upon present inputs only i. A complete study of logic circuit design is not one of our objectives, but the methods we introduce will provide a good introduction to logic design. Multiple choice questions and answers by sasmita january 9, 2020. Combinational logic circuits electronics questions and answers. Digital electronics part i combinational and sequential logic. In this article, we are going to discuss the major difference between combinational and sequential circuits. In addition to reading the questions and answers on my site, i would suggest you to check the following, on amazon, as well. Sequential circuits, which we will look at later, will feature circuits in which outputs are not determined solely by the inputs at the same time. The concept of memory is then introduced through the construction of an sr latch and then a d flipflop. These logic circuits are classified into two types.
The following section consists multiple choice questions on sequential logic circuits. Multiple choice questions on digital logic design topic combinational logics. Combinational logic design i electronic engineering. Digital logic design multiple choice questions and answers. A directory of objective type questions covering all the computer science subjects. For n input variables there are 2n possible combinations of binary input values. A combinational circuit can have an n number of inputs and m number of outputs. How digital logic gates are built using transistors. Consequently the output is solely a function of the current inputs. The digital logic circuits can be divided into two categories. Combinational logic circuit contains logic gates where its output is determined by the combination of the current inputs, regardless of the output or the prior combination of inputs.
Easy to build using jk flipflops use the jk 11 to toggle. On the other hand sequential circuits, unlike combinational logic, have state or memory. Write two characteristics of combinational circuits. Implementing combinational logic from a boolean expression to a logic circuit. These circuits do not have memory cells and their output depends only upon the current value of the input. Introduce devices that can hold state called stateholding elements read stable inputs from stateholding elements write stable outputs to stateholding elements generate outputs from inputs using combinational logic. Combinational logic circuits digital electronics tech. Some of the characteristics of combinational circuits are following. It addresses all aspects of combinational logic and provides a detailed understanding of logic gates that are the basic components in the implementation of circuits used to perform functions and operations of. Logic minimisation any boolean function can be implemented directly using combinational logic gates however, simplifying the boolean function will enable the number of gates required to be reduced.
Digital logic design multiple choice questions and answers pdf is a revision guide with a collection of trivia quiz questions and answers pdf on topics. Its output is a twobit number x1x0, representing that count in binary. Digital logic design quiz questions and answers, mcqs on logic gates, plc, combination logic, boolean algebra, algorithmic state machine, asynchronous. Combinational logic circuits digital electronics questions and. One is the combinational circuit and another one is the sequential circuit. Print the circuit diagram and the wiring diagram to pdf files. It deals with the basic principles and concepts of digital electronics. Logic gates are the simplest combinational circuits. Sequential logic combinational logic no feedback among inputs and outputs outputs are a pure function of the inputs e. It is designed for the undergraduate students pursuing courses in. Multiple choice questions and answers on digital electronics. Label all gate outputs that are a function of input variables with arbitrary. Algebraic manipulation as seen in examples karnaugh k mapping a visual approach.
As the inputs x, y, and z count from 000 to 111, the seven outputs a thru g will generate the logic required to display your date of birth on a sevensegment display. Logic gates are used to perform a logical operation with one or more inputs and generates a logical output. Combinational logic digital video lecture all about circuits. This free video contains 20 mcqs based tests on combinational logics in digital logic. The output of combinational circuit at any instant of time, depends only on the levels present at input terminals. Later, we will study circuits having a stored internal state, i. All students, freshers can download digital electronics combinational logic circuits quiz questions with answers as pdf files and ebooks.
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