[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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