[sdiy] ODP: Re: Issue with CD4024 Ripple Counter

[Roman]

This is really interesting, please don't kill this thread so soon.

One way to check if the chip had ESD accident is to pull all inputs to Vdd, measure supply current. Then pull them all to GND and measure again. If in any case it draws more than fraction of microamp, it's most probably ESD fried and goes to certified WEEE recycler (you cannot use the word trashbin nowadays). With badly fried inputs the chip might still work but draw nice miliamps via inputs.
But if there's no supply current measurable in both cases it still doesn't mean it's all good. Like covid test cannot prove you're not infected.

Roman

---- Użytkownik David G Dixon via Synth-diy napisał ----

>Hello SDIY Team,
> 
>I know, I promised that my last posting would be my last on this topic, but
>I have just one more tiny detail to share with you.
> 
>I just tested CD4024BE and CD4024BCN on the breadboard, this time clocked by
>a CD40106 hex Schmitt trigger.  The 40106 was powered with 15V (VDD) and 0V
>(VSS), and I used a 100k resistor and 100nF cap to create a square wave
>oscillator with a frequency of about 120 Hz.  The output of this oscillator
>is a perfect pulse wave that oscillates between 15V and 0V.
> 
>Results: No change.  CD4024BCN clocked normally.  CD4024BE clocked
>backwards.
> 
>If I have time today, I'm going to swing by Lee's Electronic Components on
>my way home and buy a few new CD4024BE chips to test.
> 
>If I get some new chips, and the results are any different, I'll let y'all
>know.  Otherwise, this is my last word on the topic.
>
>
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