[sdiy] SMT caps got me worrying

[Tom Farrand]

Dan,

The cap is rated at 85C.  The rule of thumb says ... for each 10C
reduction in temperature the life doubles.  How long will this cap
last at 25C (typical room temperature)?
85 - 10 = 75   X2 = 2000 Hrs
75 - 10 = 65   X2 = 4000 Hrs
65 - 10 = 55   X2 = 8000 Hrs
55 - 10 = 45   X2 = 16000 Hrs
45 - 10 = 35   X2 = 32000 Hrs
35 - 10 = 25   X2 = 64000 Hrs

64,000 Hours is 7.5 years, powered 24/7.  You won't likely power it
24/7 will you?

I suggest Panasonic FK series caps.  Many of these are available in
values that are rated at 5,000Hrs life at 105C.  They will last a good
long while.


Peace.
Tom Farrand




On Tue, May 3, 2011 at 11:37 AM, dan snazelle <subjectivity at hotmail.com> wrote:
>
> So I am starting to incorporate SMT into my projects.
>
> For the first time I am using a electrolytic  cap (a panasonic, 16volt 100uf)
>
> In the specs on Mouser it has this comment
>
> "Load life-1000 hours"
>
> WOW
>
>
> (see for yourself)
>
> 667-EEE-1CA101WAP
>
> That is less hours than there are in a year!
>
> That doesnt sound like many.
>
> My questions are
>
> 1. Does that mean the cap will DIE after 1000 hours?
> 2. Is that figure just a way for the company to cover themselves and should I actually expect many more hours?
>
>
> Thanks!
>
>
>
>
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