27 votes 27 votes The above synchronous sequential circuit built using JK flip-flops is initialized with $Q_2Q_1Q_0 = 000$. The state sequence for this circuit for the next $3$ clock cycles is $001, 010, 011$ $111, 110, 101$ $100, 110, 111$ $100, 011, 001$ Digital Logic gatecse-2014-set3 digital-logic circuit-output normal + – go_editor asked Sep 28, 2014 edited Jun 4, 2021 by Arjun go_editor 17.4k views answer comment Share Follow See all 4 Comments See all 4 4 Comments reply Punit Sharma commented Dec 3, 2018 reply Follow Share Equations will be : Q2n = Q1'Q2' + Q0'Q2 Q1n = Q2Q1'+Q2Q1 => Q2 Q0n = Q1+Q0 7 votes 7 votes smsubham commented Dec 9, 2019 reply Follow Share $Q_{ON} = Q_{1}Q_{0}' + Q_{0}Q_{0} = Q_{1}Q_{0}' + Q_{0} = (Q_{1}+Q_{0}) (Q_{0}' + Q_{0}) = Q_{1} + Q_{0}$ 0 votes 0 votes Lakshman Bhaiya commented Jan 1, 2020 reply Follow Share $Q_{Next} = J\:\overline{Q} + \overline{K}\: Q$ 3 votes 3 votes Hira Thakur commented Nov 1, 2023 i reshown by Hira Thakur Nov 1, 2023 reply Follow Share $J_2=\bar Q_1,K_2=Q_0,J_1=Q_2,K_1=\bar Q_2,J_0=Q_1,K_0=\bar Q_0$ it is a mod 5 counter whose sequence is :$000\rightarrow100\rightarrow110\rightarrow111\rightarrow011$ 0 votes 0 votes Please log in or register to add a comment.
Best answer 45 votes 45 votes Option C Gate_15_isHere answered Jan 28, 2015 edited Jun 4, 2021 by Arjun Gate_15_isHere comment Share Follow See all 0 reply Please log in or register to add a comment.
17 votes 17 votes as simple as possible Swami patil answered Jan 13, 2018 Swami patil comment Share Follow See 1 comment See all 1 1 comment reply Abhineet Singh commented Nov 10, 2020 reply Follow Share perfect solution 0 votes 0 votes Please log in or register to add a comment.
6 votes 6 votes JK ff truth table--- j k Q 0 0 Q0 1 0 1 0 1 0 1 1 Q0’ Initially Q2Q1Q0=000 Present state FF input Next state Q2 Q1 Q0 J2 K2 J1 K1 J0 K0 Q2 Q1 Q0 0 0 0 1 0 0 1 0 1 1 0 0 1 0 0 1 0 1 0 0 1 1 1 0 1 1 0 0 0 1 0 1 1 1 1 1 So ans is ( C) part. Regina Phalange answered Apr 1, 2017 Regina Phalange comment Share Follow See all 9 Comments See all 9 9 Comments reply k.eswar prasanth commented Apr 6, 2017 reply Follow Share Can u please tell me if j2 and k2 are 1 and 0 then how j1 becomes 0.....it means 1 0 gives 0 as output in jkff....????!??! I didnt get it plz calrify it... .??? 1 votes 1 votes Regina Phalange commented Apr 6, 2017 reply Follow Share @k.eswar prasanth Prasanth,it is an asynchronous counter. so initially when q2,q1,q0 is 000 then 1) J2 gets it input from q0' which is 1,K2 gets from Q0 which is 0 2) J1 gets it input from Q2 which is still 0 and similarly K1 gets from q2' which is 1 because it is asynchronous counter and each ckt is having its own clock pulse so all are working at the same time. So,when J2K2 is changing working(means changing its o/p) by that time J1K1 and J0K0 is also functioning based on previous input. This describes the difference between asynchronous ckt and synchronous ckt(where on ff o/p is in/p to another) Hope,this clarifies your doubt. 0 votes 0 votes k.eswar prasanth commented Apr 6, 2017 reply Follow Share Thank you divya how can i know the circuit is synchronous or asynchronous plzz suggest me good book for sequential circuits.... Also in question it is mention "the above Synchronous sequential...... 0 votes 0 votes Regina Phalange commented Apr 6, 2017 reply Follow Share In synchronous counter, all the flip-flops connected in the circuit are triggered by a common pulse signal and hence change states simultaneously, whereas, in an asynchronous counter, the external input pulse triggers only the first flip-flop and and its output triggers the next, whose output again triggers the third and so on. As such, in an asynchronous counter, the flip-flops change state not simultaneously but serially, one after another, triggered by the output of the previous flip-flop. For this topic you can refer floyd book for digital electronics. From page no 304 we have counter topic. 1 votes 1 votes k.eswar prasanth commented Apr 6, 2017 reply Follow Share Yes now it is clear thank you very much..... 0 votes 0 votes bhuv commented Aug 24, 2017 reply Follow Share @bikram sir Here we saw that the clock is acting simultaneously on all flip flops it is working like synchronous ckt, but the above comments are discussing it as an asynchronous ckt. So is it sync or async as there thing missing in ckt from both type of definition. To be sync. the clock should be attached to all and to be async they should be connected to one another outputs, but while solving like async i.e first taking the output of 1st flip flop and the use it for second doesn't give correct answer while if solve simultaneously all of them then option c is coming as an answer. It difficult for me to judge to put it in which of the category. 1 votes 1 votes Bikram commented Aug 24, 2017 reply Follow Share @ bhuv It is Synchronous circuit. In synchronous counter, all the flip-flops connected in the circuit are triggered by a common pulse signal and hence change states simultaneously, so when u solve this problem , solve simultaneously all of them then option c is coming as an answer . That means it is synchronous . 4 votes 4 votes bhuv commented Aug 24, 2017 reply Follow Share @bikram sir Yes, thnx for confirming. They discussed above that it is asynchronous. But I too have opinion that it is synchronous. But is it not a necessary condition that a common clock pulse connected to all flip flops must be there, but this is achieved here indirectly. Is there any other variations possible like this to be synchronous ckt. 0 votes 0 votes Bikram commented Aug 25, 2017 reply Follow Share @ bhuv See the question, it says "The above synchronous sequential circuit .." so that means we have to assume that this circuit is synchronous and proceed accordingly.. 3 votes 3 votes Please log in or register to add a comment.
0 votes 0 votes Although given answer is correct one thing worth to be noted here as it's "asynchronous circuit" and given "sign" of clock plus (-o>) which is "negative level trigger" {1-->0} So when Q2 value change form 1-->0 Q1 gets complemented Prateek kumar answered Dec 22, 2017 Prateek kumar comment Share Follow See 1 comment See all 1 1 comment reply Punit Sharma commented Dec 3, 2018 reply Follow Share it's synchronous 4 votes 4 votes Please log in or register to add a comment.