[sdiy] Switch debounce

[Scott Gravenhorst]

Can you show a schematic?  

It sounds like you want a differentiator.  You can't just connect a logic
gate (or switch) output through a cap to a CMOS logic input.  You need to
put a resistor from the CMOS input to ground to allow the cap to charge and
discharge.  Without the resistor, the CMOS input presents a very high
impedance, millions of ohms.  The size of the resistor will control how long
the pulse stays active, smaller making a narrower logic level duration.

xyzzy at sysabend.org wrote:
>I'm having some troubles with a circuit that has simple switch debounce
>stuph on it.  The circuit is a 4001 based clock generator going through a
>.01uf cap, there is also another push button to do a manual pulse.  I get a
>nice waveform out of the 4001, but going through the cap turns it into a
>very momentary pulse which the logic following it doesnt seem to accept.
>Same for the pushbutton.
>
>Quite possible this cold is making me fuzzy enough that I'm not forming the
>question correctly, but is .01uf a good value for this? ( given the limited
>information I've provided. ).  At two places in the circuit ( which is
>kitbashed from multiple other circuits ) I've used a .01 cap and in both
>cases the logic following it doesnt see the momentary pulse as a clean
>pulse, but I'd assume that the original circuit worked correctly.
>
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