At 04:57 PM 5/1/2013, you wrote:
>I'm feeling quite like an idiot..because this should be=20
>obvious...and so simple...its EE101 stuff
>
>74HC74 dual D flip flop
>
>clear and preset tied high (5V) thru a resistor (10K)
>
>D connected to !Q
>
>clock driven by a 555 timer as a one shot from an external trigger
>
>Q drives into another circuit
>
>Customer does NOT want a programmable part....
>
>So the 555 generates the active high pulse just fine
>
>The D ff doesnt behave.  The Q ouput just follows the length of the=20
>clock pulse.    It should toggle states on each rising edge of the=20
>555 ouput.  Q out is low,!Q is high, clock comes in....D goes=20
>hi...but goes back low when the clock pulse goes away.
>
>grrrrrrrr.......
high)?

Haywired? Or nicely laid out?

Is it a CMOS "555" with proper CMOS logic levels on the output?

Try disconnecting that thing wot it's driving in case you're getting=20
ground bounce
causing a double tap.


--=20
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