Connect with us

any substitute ofr JK flip flop??

Discussion in 'Electronic Basics' started by Ankur, Feb 23, 2004.

Scroll to continue with content
  1. Ankur

    Ankur Guest

    After lot many attempts , i m unable to use the JK flip flop .. don't
    know wht the problem is !
    neways, i wish 2 get something which has a control input and toggles
    at the falling edge. Is there any other device/circuit through which i
    can achieve this ??
    (Pls tellme those which require lesser no. of components as i m
    running short of breadboard space)

    TIA
    ankur
     
  2. CFoley1064

    CFoley1064 Guest

    Subject: any substitute ofr JK flip flop??
    Unless you're running short of patience, you might want to give that J-K FF
    another try. You don't indicate what chip you're using, or what your power
    supply voltage is, so we're kind of in the dark. Here's what to do to make a
    74HC76 act like a toggle FF with NGT clock transitions: (read in fixed font or
    use M$ Notepad)

    J-K FF Set as a Toggle FF
    VCC
    +
    VCC |
    + .-----o-----.
    | | Set |
    '--o J Q o
    | 1/2 |
    | 74HC76 |
    Input Clock | |
    o------------o CLK' |
    VCC | |
    + | |
    | | |
    '--o K Q'o
    | |
    | Reset |
    '-----o-----'
    |
    VCC |
    + |
    | |
    | |
    '---'

    The old 74 series pinouts are probably a good choice because of your
    requirement of a NGT clock. If this doesn't work for you, check your pinouts
    -- you might have things wired wrong. Also, the IC might be damaged (believe
    it or not, it does happen!)

    The other J-K FFs have a similar setup, although some like the 7473 and 74107
    have clear only. You could also use a D FF, but on the standard TTL pinout
    ICs, there is usually a common clock for all the FFs. Usually you want a
    little more latitude.

    If you're using the 7476, there are a couple of gotchas -- read the data sheet!
    Also, make sure you have clean, debounced fast rise- and fall-time clock
    inputs -- that can cause major headaches.

    Good luck
    Chris
     
  3. You can use a DFF ('74, or some such) with the 'Qbar' tied back
    to the 'D' for a toggle. If you *really* need negative edge
    triggering you can wire up the other half of the package as an
    inverter (using the Set/Reset pins).
     
  4. Lord Erdel

    Lord Erdel Guest

    cant you just invert your input signal?
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-