decoder not working

Discussion in 'General Electronics Chat' started by marijannovak123, Dec 16, 2014.

  1. marijannovak123

    Thread Starter New Member

    Dec 16, 2014
    3
    0
    Hello!

    https://www.dropbox.com/s/tiknsfvfjhfq4ll/stepper.gif?dl=0

    I am making a stepper driver, and connecting everything according to this diagram the decoder gives logic 1 only at q2 and q3 ..and they alternate in the constant rythm..q0 and q1 stay at logic 0 whole the time..when i try to connect decoder by itself and change the inputs myself it works as it's supposed to..but with the counter it doesn't..what could be the problem? thanks
     
  2. jjw

    Member

    Dec 24, 2013
    173
    31
    This may not solve the problem, but the 100 ohm resistance in the oscillator is way too low.
    You could use 100k and change the capacitor to 1uF.
     
  3. marijannovak123

    Thread Starter New Member

    Dec 16, 2014
    3
    0
    I am using 10uF and 50K potentiometer actually
     
  4. jjw

    Member

    Dec 24, 2013
    173
    31
    Have you checked QA of the counter and A input of the decoder, are they changing?
    They might be stuck at 5V.
    Are the outputs of the decoder connected to something?

    Edit: actually it might concern output QB and input B
     
    Last edited: Dec 18, 2014
  5. ScottWang

    Moderator

    Aug 23, 2012
    4,850
    767
    1. Please upload the file to the forum.
    2. Change 10uf to 1 uf or less and try again.
    3. If it still didn't work then you could in series another gate with clk(Pin 15).
     
  6. marijannovak123

    Thread Starter New Member

    Dec 16, 2014
    3
    0
    Thanks everyone, I solved the problem. Apparently the B input was stuck at +5V although it's pin was changing voltage as the counter's outputs..anyway i grounded B, and used A and C..therefore I had to use different outputs too..so I'm using Y0,Y1,Y6,Y7
     
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