1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Jk flip flop

  1. Jan 26, 2006 #1
    does anybody knows how to read the table or has any explanation for jk flip flop??any website recommended pls.........
  2. jcsd
  3. Jan 26, 2006 #2


    User Avatar

    Staff: Mentor

    Just check out the datasheet for a typical JK FF. It should have what you need. Here's a link to the Texas Instruments 74HC112 datasheet on Jameco's website:

    http://rocky.digikey.com/scripts/ProductInfo.dll?Site=US&V=296&M=SN74HC112N [Broken]
    Last edited by a moderator: May 2, 2017
  4. Jan 26, 2006 #3


    User Avatar
    Science Advisor

    That flip flop is probably a little more complicated than what he needs since it includes "pre" and "clr" inputs. The wikipedia article has a slightly simpler one:

    (the J-K flip flop truth table halfway down the page)

    The flip flop has 2 inputs, J and K (and also the clock). It remembers what the output Q was previously. On a clock edge, if J and K are 0, then the output Q remains unchanged. If J and K are 1, then the output Q flips from a 0 to a 1 or from a 1 to a 0. If K is 1 and J is 0, Q is set to 0, and if K is 0 and J is 1, Q is set to 1.
  5. Jan 26, 2006 #4
    What helped me was understanding fully basic idea of flip-flop and what S-R ff does, then J-K is just S-R with only difference in 11 input, where S-R goes unstable while J-K toggles (complements current state).

    But basically, as was said above: Q' is what you are "concerned" about, i.e. next state. Q' is a ff-particular function that depends on inputs J and K and present state Q. In other words, D and JK ff react (or have Q' function) differently to the same inputs and current state Q.
    Last edited: Jan 26, 2006
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook