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A modulus -12 ring counter requires a minimum of

  1. 10 flip-flops
  2. 12 flip-flops
  3. 8 flip-flops
  4. 6 flip-flops
in Digital Logic by Active (2.5k points)
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  • A ring counter is a circular shift register with only one flip-flop being set at any particular time; all others are cleared.
  • A $k$ - bit ring counter circulates a single bit among the flip flops to provide $k$ distinguishable states.

 

3 Answers

+12 votes
Best answer
12 flip flops required.
In ring counter, n flip flops generate n states where in twisted ring counter n flip flops generate 2n states.
for more info
http://www.electronics-tutorials.ws/sequential/seq_6.html
by Active (3.1k points)
0

Answer should be 6.

There are two types of ring counters.

(i) Straight ring counter -needs 12 flipflops  (ii)Twisted ring counter - needs 6 flipflops.

Minimum is 6.

Reference:https://en.wikipedia.org/wiki/Ring_counter

    0
    they have said ring counter if they meant twisted ring they should have specified it. i think 12 is the answer
    0

    Then why they have used word Minimum?. 

    Just search in google about "types of Ring Counter". Also see this http://www.worldofcomputing.net/digital-electronics/ring-counters.html , http://ds.opdenbrouw.nl/digse1/ring_counters.pdf

    What is the answer given by isro?

    0
    acc. to ISRO answer key answer is 12 but i think answer is 6.
    +3
    Those who answered 6 must complain.
    0
    minimum was the part of question i think. like minimum memory required . there are 4 option . but giving option 6 made it ambiguous. i think u should demand for marks on both 12 and 6.
    0
    Answer is b) 12 flip-flops

    The “MODULO” or “MODULUS” of a counter is the number of states the counter counts or sequences through before repeating itself and a ring counter can be made to output any modulo number.

    A “mod-n” ring counter will require “n” number of flip-flops connected together to circulate a single data bit providing “n” different output states.

    For example, a mod-8 ring counter requires eight flip-flops and a mod-16 ring counter would require sixteen flip-flops.
    0
    plzz give 2015 and 2014 isro answer key.
    0
    +1 vote
    Answer- 12 flip flop
    by Loyal (9.9k points)
    0 votes

    For any counter:-

    1. There are a certain number of Flip Flops from which it is built.
    2. There are a certain number of states that the counter can be in. Each state represents a unique value.

    Synchronous Counters:

    $n$ Flip Flops count $2^n$ different values.

    Or you can say that $n$ Flip Flops result in $2^n$ states, and each state represents a distinguishable value.


     

    Asynchronous Counters (aka Ripple Counters):

    $n$ Flip Flops count $2^n$ different values.

    Or you can say that $n$ Flip Flops result in $2^n$ states, and each state represents a distinguishable value.


     

    Johnson Counter: (aka Twisted Ring Counter, Switch-Tail Ring Counter)

    $n$ Flip Flops count $2n$ different values.

    Or you can say that $n$ Flip Flops result in $2n$ states, and each state represents a distinguishable value.


     

    Ring Counters:

    $n$ Flip Flops count $n$ different values.

    Or you can say that $n$ Flip Flops result in $n$ states, and each state represents a distinguishable value.

     

    Now unless explicitly mentioned otherwise, a ring counter should be assumed as a straight ring counter, which leads us to Option B

    by Loyal (6.6k points)
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