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Postby gasman » Wed Mar 10, 2010 9:08 pm

"What can possibly go wrong?"
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Postby MAGN1T » Fri Mar 12, 2010 9:55 am

fivebob wrote:And you claim to be involved in electronics :roll:

FYI R-C debounce circuitry is not used that much in modern circuits due to it's slow response times and as you mentioned the failure of components, either a dedicated chip like the Motorola MC14490 or 100% software debounce seems to be the preferred method, no capacitors involved at all ;)


The motorola chip won't work without an external capacitor added.

It even says so in the data sheet.

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Postby Mr Revhead » Fri Mar 12, 2010 9:59 am

Actually doesn't it say it only needs one to adjust to a desired frequency?
Now I am far from an expert on electronics, but I don't read that as "it won't work unless...."
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Postby fivebob » Fri Mar 12, 2010 10:32 am

MAGN1T wrote:The motorola chip won't work without an external capacitor added.

That's funny I have one working without a capacitor ;)
It even says so in the data sheet.

Actually it doesn't say that, what it does say is that if you don't use an external clock source on OSCin you can use a capacitor between OSCin and OSCout to generate a clock signal internally.

Regardless of that, capacitors are not as prone to failure as you imply. The cap that I would use to generate the clock signal if I didn't already have one would be 390pf and using the worst case scenario on http://www.sqconline.com/reliability/capacitor1.html gives a MTBF of 22,000,000hrs or around 2211yrs.
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Postby Mr Revhead » Fri Mar 19, 2010 1:01 pm

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