Help with logic truth tables

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Hi
 It is years since I dabbled in electronics. I need a J K Flip Flop
(4000 series) J=K=1  Toggles on clock pulse (positive or negative).
J=K=0 No change. I thought all JKs did this but  4027 truth table is
strange.



Re: Help with logic truth tables

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Que? This one is exactly as per your description.

http://www.datasheetcatalog.org/datasheet/philips/HEF4027BP.pdf

Or are you saying that the actual device isn't behaving in accordance with
the truth table? In that case, the problem could be unterminated pins,
supply rail noise or contact bounce on an input.



Re: Help with logic truth tables

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He's expecting the thing to toggle on either edge of the clock,
not a standard thing.  Datasheet says it flips on rising clock
edge only.  

Perhaps try an xor with RC to one input, to make a clock pulse
___/\___ from each incoming edge?  

Grant.

Re: Help with logic truth tables

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He said positive OR negative, not positive AND negative.
I don't think he meant both, eh?








Re: Help with logic truth tables
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Then there are those who understand digital and those that don't.

It might be better if the Original Poster explains what the requirement
is, rather than persist trying to make a flawed implementation work.

Re: Help with logic truth tables

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Download one of the free spice simulation packages and have a play.



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