2 votes 2 votes Find the Mod Value for the counter My ans is MOD-5 counter but given is MOD-3 please explain .... Digital Logic digital-logic digital-counter + – Anjan asked Jan 10, 2018 Anjan 728 views answer comment Share Follow See all 10 Comments See all 10 10 Comments reply Anjan commented Jan 10, 2018 reply Follow Share give the counting sequence also ..... 0 votes 0 votes Anu007 commented Jan 10, 2018 reply Follow Share negative edge FF given ie. work on 1 -0 transition. 0 votes 0 votes skyby commented Jan 10, 2018 reply Follow Share i'm unable to understand what's the role of PR . is it enable ? if yes then how it is working 0 votes 0 votes Shivam Chauhan commented Jan 10, 2018 reply Follow Share PR is preset (This sets all output of flip flops to 1) It looks active high preset therefore when $Q_3$$Q_2$$Q_1$ = 010 all flip flops gets set. Sequence of states: 0 0 0 --> 0 0 1 --> 0 1 0 (before next negative edge all flip flops gets set) 111 --> 000 repeat so total 3 different states MOD-3 counter 2 votes 2 votes stblue commented Jan 11, 2018 reply Follow Share @shivam chauhan whenever output of and gate is 0, then flip flop is going to reset to its inital value ? 0 votes 0 votes Shivam Chauhan commented Jan 11, 2018 reply Follow Share I don't see any bubble indicating active low. 0 votes 0 votes Anjan commented Jan 11, 2018 reply Follow Share Preset is active high here,means it makes FF to set to 1 , whenever it get a i/p 1. Sequence of counting should be 111,110......as soon as it see 010 it resets to 111 unique states are 7,6,5,4,3 which means 5 states. -- >MOD-5 am i wrong?? 0 votes 0 votes stblue commented Jan 11, 2018 reply Follow Share Its binary up counter, so you can't go from 7,6,5,4,3. 0 votes 0 votes Anjan commented Jan 11, 2018 reply Follow Share then why values are presetted at some point of time to 111 ? I think its down counter. So that values after entering to undesired state presets to initial state 111 0 votes 0 votes Anjan commented Jan 11, 2018 reply Follow Share Shivam Chauhan how 111 to 000 happens atlast ?? 0 votes 0 votes Please log in or register to add a comment.