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Homework Help: Using a SR flip-flop to make a particular circuit

  1. Feb 18, 2013 #1
    1. The problem statement, all variables and given/known data
    A Null-Lobur flip-flop (NL flip-flop) behaves as follows: If N = 0, the flip-flop does not change state. If N = 1, the next state of the flip-flop is equal to the value of L.

    a) Derive the characteristic table for the NL flip-flop.

    b) show how an SR flip-flop can be converted to a NL flip-flop by adding gate(s) and inverter(s).

    2. Relevant equations

    3. The attempt at a solution

    I believe i got part a right which is:

    if N is 0 and L is 0, Q(t+1) = Q(t) -> no change
    if N is 0 and L is 1, Q(t+1) = Q(t) -> no change
    if N is 1 and L is 0, Q(t+1) = 0 -> L
    if N is 1 and L is 1, Q(t+1) = 1 -> L

    However, I really am not sure at all on how to do the second part. My professor hasn't done any examples like this and I had no luck searching through the book. Any help on how to go about doing this other then just guess and check (which would take forever)?
  2. jcsd
  3. Feb 18, 2013 #2
    I think I actually figured it out but using a JK flip flop rather than only an SR flip- flop...


    Not sure how to fix the undefined issue with 1 - 1 going into the SR without using the JK....any suggestions?
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