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 Not Counting Properly in Actual Circuit

  1. Mar 8, 2017 #1
    1. The problem statement, all variables and given/known data
    Hello everyone. I tried practicing creating up down counters using the J/K FF. I've been using the Synchronized Clock with an up down counter and the simulation seems to be successful based on this circuit on the image

    However, in the actual circuit in a breadboard using a 74LS73 IC, a 555 timer with the capacitor and resistors, and an 74LS86, it somehow lags after counting to the max and sometimes refuses to count further for a few seconds . For example, after it successfully counts up to 3, it doesn't go immediately to 0 and instead goes to 2 and goes back to 3 again until it snaps out of it. When it counts down to 0, it refuses to go back to 3 and vice versa. It still counts up and down based on the switch but I don't know what's the problem with this.

    The asynchronous 3 bit down D counter works very well in the breadboard. I wonder what's causing this? An IC problem perhaps?
    2. Relevant equations

    3. The attempt at a solution

  2. jcsd
  3. Mar 9, 2017 #2
    I can't tell from the drawing, but is the flip flops clear pin tied high?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted