>
>At 09:22 AM 3/4/99 -0800, you wrote:
>
>>>? However, comparing a ripple-current rating for 105 deg C with a ripple
>>current rating for 85 degrees C is hardly valid. My guess is that 105
>>deg C capacitors are going to last longer in a typical anode supply.
>>
>I think John's point is that higher max. operating temperature rating seems
>to automatically imply some other performance enhancements over an 85 C
>rated cap, and I can't see that it does. Choosing the cap with the 105
>deg.C rating, mainly because of that rating, may be false economy if the
>max ripple current rating is only marginal for the application. Mallory
>and Phillips still provide the ripple current rating at 85 C, even for
>their 105 C caps. This implies that the max ripple current rating drops
>(substantially ?) as the temp rises from 85 to 105 deg. C (even though the
>'C' and ESR remain stable). The temp rating only assures that the 'C' and
>ESR will remain within specs up to those temps, without a permanent change
>in either occurring. There's no mention of what happens to ripple current
>rating.
>
>There's no indication from either supplier's catalogs that running a cap at
>well below the max design temp will result in longer life,
? As I understand it, the lifespan of an electrolytic capacitor approx.
doubles for each ten degrees C below its rated operating temp. --
provided that the temp. stays above the minimum allowable.
- later, Phil
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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