pic microcontroller discussion list wrote:
> On Tue, 10 Feb 2004 23:22:06 -0000, Alexander JJ Rice
> <a.j.j.rice@durham.ac.uk> wrote:
>
>   Vishay rate their 805 SMT thick film devices for an overload of
>> 1A
>> for 5 seconds. That is 5 Joules.
>
> woops, silly me. E=I^2 * RT and it is 0.5 seconds, not 5 seconds so :
>
> 1^2 * 3.9 * 0.5 =  1.8J
>

thanks for taking the time. I didn't think to estimate the heat-rise.
I tried duplicating the failure by setting up a litle PIC circuit that
just turns this thing on and off. I'm even discharging the cap via a
relay to ensure it starts at zero. 2,500 cycles later it is still ticking.

Phil Eisermann
Electronics Engineer
The Ridge Tool Company
(440)329-4680

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