[sdiy] Issue with CD4024 Ripple Counter

David G Dixon dixon at mail.ubc.ca
Fri Sep 17 20:48:00 CEST 2021


So, I went to the lab and set up a little breadboard.  I put 4024 on it,
used my +15V and 0V rails to power it (yes, I decoupled with 104), and I
also set up a TL072 as a comparator driven by a triangle-wave LFO.  I sent
the output of the comparator through a diode to have it go just between 0V
and +15V.  I tried clocking two CD4024BEs, two CD4024BCNs, and one
MC14024BCP.  The CD4024BCNs didn't even work.  The CD4024BEs gave me some
really hashy looking outputs.  The MC14024BCP worked perfectly.  Then I
tested them in an ASR, with similar results.

So, I threw all of the CD4024s into the trash.  Unfortunately, I only have
one MC14024B.  I'm going to buy more, cuz they work well, without any
issues.

Lesson learned, I guess.  I'm just not sure what the lesson is, other than
"don't use CD4XXX chips" or at least ones with edge-driven inputs.
Argghh!!!  Why can't this stuff just work?  It's a miracle that we aren't
still living in caves, wearing skins and hunting sabre-tooth tigers with
sticks.



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